fix(map): the hero map's fade to the header was hardcoded white

The fade between the map band and the school header ramped through
rgba(255,255,255,...) and landed on var(--bg-card). In the light theme
that is white into white and invisible, as designed. In the dark theme
it climbed to 95% WHITE and then met a near-black card, putting a bright
band across the full width exactly where the map should dissolve into
the title.

Fading to the colour the gradient lands on is the whole trick, and it
only works if that colour is a token — so --bg-card-rgb now exists in
both theme blocks, matching the --hero-ground-rgb precedent.

Two more defects in the same file, same cause, found while in there:

The controls floating over the map paired a hardcoded white background
with color: var(--text-primary), which resolves to #E9EEF0 in dark —
near-white text on a near-white button. These deliberately do NOT follow
the theme, because the map tiles are light in both, so the ink is now
literal too and says why. A themed token is the wrong tool for a surface
that never changes.

The loading skeleton swept 50% white across var(--bg-secondary), which
is a bright flash every 1.4s on a dark page. It now sweeps toward the
card colour, a shade lighter than the ground in both themes.

The guard is a stylesheet test rather than a render test, because the
bug is invisible in the theme it was written for. Verified by reverting
each fix in turn: it names .fade and .openHint exactly.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015mWQnpye9F299NVRCCSRvj

backend/app.py

@@ -6,6 +6,7 @@ Uses real data from UK Government Compare School Performance downloads.
 
 import hashlib
 import re
+import time
 from contextlib import asynccontextmanager
 from datetime import datetime, timezone
 from typing import Optional
@@ -15,7 +16,7 @@ import pandas as pd
 from fastapi import FastAPI, HTTPException, Query, Request, Depends, Header
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.middleware.gzip import GZipMiddleware
-from fastapi.responses import FileResponse, Response
+from fastapi.responses import FileResponse, JSONResponse, Response
 from fastapi.staticfiles import StaticFiles
 from slowapi import Limiter, _rate_limit_exceeded_handler
 from slowapi.util import get_remote_address
@@ -33,6 +34,7 @@ from .data_loader import (
     get_supplementary_data,
     get_supplementary_data_batch,
     search_schools_typesense,
+    suggest_schools_typesense,
 )
 from .data_loader import get_data_info as get_db_info
 from . import flags
@@ -296,8 +298,101 @@ def clean_filter_values(series: pd.Series) -> list[str]:
 # SECURITY MIDDLEWARE & HELPERS
 # =============================================================================
 
-# Rate limiter
-limiter = Limiter(key_func=get_remote_address)
+def client_key(request: Request) -> str:
+    """The rate-limit bucket: the real caller, not the proxy in front of them.
+
+    `get_remote_address` reads request.client.host. In staging and production
+    the backend has no published ports and sits on the internal network, so its
+    only caller is the Next proxy — meaning every browser user on the site
+    shared one bucket. Measured before this fix: 70 concurrent requests to
+    /api/schools returned 60 OK and 10 refused.
+
+    CF-Connecting-IP first, because Cloudflare (in front of both environments)
+    sets it on every origin request and *overwrites* any client-supplied value,
+    which a parsed X-Forwarded-For chain does not guarantee. The XFF fallback is
+    forgeable, but only by a caller already inside the Docker network, which is
+    the one place nothing untrusted can reach.
+    """
+    cf = request.headers.get("cf-connecting-ip")
+    if cf:
+        return cf.strip()
+    xff = request.headers.get("x-forwarded-for")
+    if xff:
+        return xff.split(",")[0].strip()
+    return get_remote_address(request)
+
+
+# Per-client limiter. Paired with the global ceiling below — the two do
+# different jobs and neither substitutes for the other.
+limiter = Limiter(key_func=client_key)
+
+
+# --- The ceiling no header can raise ----------------------------------------
+#
+# client_key trusts CF-Connecting-IP, and nothing in this process can tell an
+# edge-set header from an attacker-set one. That distinction can only be made
+# at Cloudflare, with Authenticated Origin Pulls or an origin firewall. A
+# caller reaching the origin directly could otherwise mint a fresh rate-limit
+# bucket per request and evade per-client limits entirely — which would make
+# correct keying a net regression against abuse, since the single shared bucket
+# it replaced at least capped everyone at 60/minute together.
+#
+# So per-client limits give fairness, and this gives the origin a hard total.
+# It does not make the header trustworthy; it bounds what trusting it can cost.
+# The header problem itself is closed at Cloudflare, not here.
+#
+# [window_start_monotonic, count], or None before the first request. A fixed
+# window is crude, which is right for a backstop: it has to be obviously
+# correct rather than fair.
+_global_window: Optional[list] = None
+
+# The container healthcheck runs `curl http://localhost:80/api/data-info` from
+# inside the container. Starving it would fail the check, restart the
+# container, and turn a load spike into an outage loop — the ceiling exists to
+# protect the origin, not to kill it.
+_LOCAL_HOSTS = frozenset({"127.0.0.1", "::1", "localhost"})
+
+
+def exempt_from_ceiling(request: Request) -> bool:
+    """Whether the ceiling should ignore this request.
+
+    Its own function so the rule is testable without standing up a server —
+    and so the healthcheck exemption is somewhere a reader can find it.
+    """
+    if not request.url.path.startswith("/api/"):
+        return True
+    # The peer address, never the Host header: Host is set by the caller and
+    # would hand every attacker an exemption.
+    return (request.client.host if request.client else "") in _LOCAL_HOSTS
+
+
+class GlobalRateLimitMiddleware(BaseHTTPMiddleware):
+    """A cap on total /api/ traffic, independent of any client identity."""
+
+    async def dispatch(self, request: Request, call_next):
+        global _global_window
+
+        if exempt_from_ceiling(request):
+            return await call_next(request)
+
+        now = time.monotonic()
+        # One event loop, and no await between the read and the write, so this
+        # sequence is atomic without a lock.
+        if _global_window is None or now - _global_window[0] >= 60:
+            _global_window = [now, 0]
+        _global_window[1] += 1
+
+        if _global_window[1] > settings.global_rate_limit_per_minute:
+            return JSONResponse(
+                # Distinguishable from slowapi's per-client 429: an operator
+                # reading logs has to be able to tell "one noisy client" from
+                # "the origin is saturated".
+                {"detail": "The service is at capacity. Please retry shortly."},
+                status_code=429,
+                headers={"Retry-After":
+                         str(max(1, int(60 - (now - _global_window[0]))))},
+            )
+        return await call_next(request)
 
 
 class SecurityHeadersMiddleware(BaseHTTPMiddleware):
@@ -355,6 +450,7 @@ CACHE_RULES: list[tuple[str, tuple[int, int, int]]] = [
     ("/api/schools/",           (300,  3600,  86400)),  # /api/schools/{urn}
     ("/api/rankings",           (60,   600,   3600)),
     ("/api/compare",            (60,   600,   3600)),
+    ("/api/suggest",            (60,   3600,  86400)),  # autosuggest
     ("/api/schools",            (30,   300,   1800)),   # search list
 ]
 
@@ -502,6 +598,10 @@ app.add_middleware(CacheAndETagMiddleware)
 app.add_middleware(SecurityHeadersMiddleware)
 app.add_middleware(RequestSizeLimitMiddleware)
 app.add_middleware(GZipMiddleware, minimum_size=512)
+# Added last, so it is outermost and refuses before anything downstream does
+# work. A ceiling that only applies after the expensive part has run is not a
+# ceiling.
+app.add_middleware(GlobalRateLimitMiddleware)
 
 # CORS middleware - restricted for production
 app.add_middleware(
@@ -1271,6 +1371,38 @@ async def get_place(request: Request, kind: str, slug: str,
     }
 
 
+# Two characters. One is not a query — it matches thousands of schools and the
+# response is useless, so it is not worth a round trip.
+SUGGEST_MIN_QUERY = 2
+
+
+@app.get("/api/suggest")
+@limiter.limit("120/minute")
+async def suggest_schools(
+    request: Request,
+    q: str = Query("", max_length=100),
+    limit: int = Query(8, ge=1, le=20),
+):
+    """School name suggestions, from Typesense alone.
+
+    Deliberately not a mode of /api/schools: that path filters and sorts the
+    full in-memory DataFrame, which is far too expensive to run per keystroke.
+
+    Nothing here returns an error for ordinary input. A short query, no
+    matches, or Typesense being unreachable are all 200 with an empty list —
+    a dropdown that quietly does not appear is the right failure for a
+    keystroke path, and there is no DataFrame fallback because the 25,000-row
+    substring scan is precisely what this endpoint exists to avoid.
+
+    120/minute rather than the default 60: a 200 ms debounce makes typing
+    legitimately bursty.
+    """
+    query = q.strip()
+    if len(query) < SUGGEST_MIN_QUERY:
+        return {"suggestions": []}
+    return {"suggestions": suggest_schools_typesense(query, limit)}
+
+
 @app.get("/api/flags")
 @limiter.limit(f"{settings.rate_limit_per_minute}/minute")
 async def get_feature_flags(request: Request):

backend/config.py

@@ -35,6 +35,11 @@ class Settings(BaseSettings):
     # Security
     admin_api_key: str = Field(default_factory=lambda: secrets.token_urlsafe(32))
     rate_limit_per_minute: int = 60  # Requests per minute per IP
+    # A ceiling on total /api/ traffic, independent of any client identity.
+    # client_key trusts headers only Cloudflare can vouch for, so a caller
+    # reaching the origin directly could otherwise mint a fresh bucket per
+    # request. See GlobalRateLimitMiddleware in backend/app.py.
+    global_rate_limit_per_minute: int = 3000
     rate_limit_burst: int = 10  # Allow burst of requests
     max_request_size: int = 1024 * 1024  # 1MB max request size
 

backend/data_loader.py

@@ -100,6 +100,58 @@ def search_schools_typesense(query: str, limit: int = 250) -> List[int]:
         return []
 
 
+# The most a public endpoint will return in one response.
+SUGGEST_MAX_LIMIT = 20
+
+# Fields a suggestion row carries, and the default when the document omits an
+# optional one. phase and school_type are optional in the Typesense schema.
+_SUGGEST_FIELDS = ("school_name", "local_authority", "postcode",
+                   "phase", "school_type")
+
+
+def suggest_schools_typesense(query: str, limit: int = 8) -> List[dict]:
+    """Autosuggest rows straight from Typesense. Never raises.
+
+    Returns documents rather than URNs, unlike search_schools_typesense, so the
+    caller needs no DataFrame. Every field below is already in the index — see
+    pipeline/scripts/sync_typesense.py — which is what makes this cheap enough
+    to run per keystroke.
+    """
+    client = _get_typesense_client()
+    if client is None:
+        return []
+    try:
+        result = client.collections["schools"].documents.search({
+            "q": query,
+            "query_by": "school_name,local_authority",
+            "per_page": max(1, min(limit, SUGGEST_MAX_LIMIT)),
+            "typo_tokens_threshold": 1,
+        })
+    except Exception:
+        # A dropdown that quietly stops appearing is the right failure here.
+        return []
+
+    rows = []
+    for hit in result.get("hits", []) or []:
+        doc = (hit or {}).get("document") or {}
+        try:
+            urn = int(doc["urn"])
+        except (KeyError, TypeError, ValueError):
+            # Skip the row, keep the rest. Typesense declares urn as int32 so
+            # this should be unreachable, but the index is a separate system
+            # that something other than this code can reindex — and "never
+            # raises" is a promise the keystroke path actually depends on.
+            # Dropping one malformed document is right; blanking the whole
+            # dropdown, or serving a suggestion pointing at /school/0, is not.
+            logging.getLogger(__name__).warning(
+                "skipping malformed suggestion document: %r", doc)
+            continue
+        row = {"urn": urn}
+        row.update({f: str(doc.get(f, "") or "") for f in _SUGGEST_FIELDS})
+        rows.append(row)
+    return rows
+
+
 def normalize_school_type(school_type: Optional[str]) -> Optional[str]:
     """Convert cryptic school type codes to user-friendly names."""
     if not school_type:

backend/flags.py

@@ -50,6 +50,13 @@ REGISTRY: dict[str, Flag] = {
             ),
             added=date(2026, 8, 23),
         ),
+        Flag(
+            name="school_autosuggest",
+            description=(
+                "School name suggestions as you type in the main search box."
+            ),
+            added=date(2026, 8, 26),
+        ),
     )
 }
 

backend/tests/test_rate_limit_key.py

@@ -0,0 +1,147 @@
+"""The rate-limit bucket must be the caller, not the proxy in front of them.
+
+`get_remote_address` reads request.client.host. In staging and production the
+backend has no published ports and its only caller is the Next proxy, so that
+host is the Next container — one bucket for every browser user on the site.
+Measured before this fix: 70 concurrent requests, 60 served and 10 refused.
+"""
+
+from starlette.datastructures import Headers
+
+from backend.app import client_key
+
+
+class _Req:
+    """Enough of a Request for the key function: headers and a client host."""
+
+    def __init__(self, headers: dict, host: str = "10.0.0.9"):
+        self.headers = Headers(headers)
+        self.client = type("C", (), {"host": host})()
+        self.scope = {"type": "http", "client": (host, 0),
+                      "headers": [(k.lower().encode(), v.encode())
+                                  for k, v in headers.items()]}
+
+
+def test_cloudflare_header_wins():
+    # Cloudflare sets CF-Connecting-IP and overwrites any client-supplied
+    # value, so it is trustworthy in a way a parsed XFF chain is not.
+    assert client_key(_Req({"cf-connecting-ip": "203.0.113.7"})) == "203.0.113.7"
+
+
+def test_forwarded_for_is_the_fallback_and_takes_the_first_entry():
+    # Left-most is the original client; everything after it is proxies.
+    assert client_key(
+        _Req({"x-forwarded-for": "203.0.113.7, 10.0.0.2"})) == "203.0.113.7"
+
+
+def test_remote_address_is_the_last_resort():
+    assert client_key(_Req({}, host="10.0.0.9")) == "10.0.0.9"
+
+
+def test_cloudflare_header_beats_forwarded_for():
+    key = client_key(_Req({"cf-connecting-ip": "203.0.113.7",
+                           "x-forwarded-for": "198.51.100.1"}))
+    assert key == "203.0.113.7"
+
+
+def test_two_callers_get_two_buckets():
+    # The whole point: one user exhausting their limit must not refuse another.
+    a = client_key(_Req({"cf-connecting-ip": "203.0.113.7"}))
+    b = client_key(_Req({"cf-connecting-ip": "203.0.113.8"}))
+    assert a != b
+
+
+def test_whitespace_is_stripped():
+    # "a, b" split on comma leaves a leading space on every entry but the
+    # first; an unstripped key silently creates a second bucket per client.
+    assert client_key(_Req({"x-forwarded-for": " 203.0.113.7 ,10.0.0.2"})) \
+        == "203.0.113.7"
+
+
+# ---------------------------------------------------------------------------
+# The ceiling that header rotation cannot raise.
+# ---------------------------------------------------------------------------
+
+import pytest
+from fastapi.testclient import TestClient
+
+
+@pytest.fixture()
+def api(monkeypatch):
+    from backend import app as app_module
+    from backend.config import settings
+
+    monkeypatch.setattr(settings, "global_rate_limit_per_minute", 5)
+    monkeypatch.setattr(app_module, "_global_window", None)
+    return TestClient(app_module.app, raise_server_exceptions=False)
+
+
+
+def _ceiling_req(path: str, host: str):
+    """Enough of a Request for exempt_from_ceiling: a path and a peer host."""
+    return type("R", (), {
+        "url": type("U", (), {"path": path})(),
+        "client": type("C", (), {"host": host})(),
+    })()
+
+
+def _get(client, path="/api/flags", cf=None):
+    headers = {"cf-connecting-ip": cf} if cf else {}
+    return client.get(path, headers=headers)
+
+
+def test_rotating_the_cloudflare_header_cannot_buy_unlimited_requests(api):
+    """The attack the per-client keying opened up.
+
+    client_key trusts CF-Connecting-IP, and nothing in this process can tell an
+    edge-set header from an attacker-set one — that distinction can only be
+    made at Cloudflare, with Authenticated Origin Pulls or an origin firewall.
+    A caller reaching the origin directly can therefore mint a fresh
+    rate-limit bucket per request and evade per-client limits entirely.
+
+    Per-client fairness is still the right default; this is the backstop that
+    bounds what evading it can achieve. Without it, correct keying would be a
+    net regression against abuse compared with the shared bucket it replaced.
+    """
+    codes = [_get(api, cf=f"203.0.113.{i}").status_code for i in range(8)]
+    assert codes.count(200) == 5
+    assert codes.count(429) == 3
+
+
+def test_the_ceiling_says_which_limit_was_hit(api):
+    # Distinguishable from slowapi's per-client 429, or an operator reading
+    # logs cannot tell "one noisy client" from "the origin is saturated".
+    for i in range(5):
+        _get(api, cf=f"203.0.113.{i}")
+    refused = _get(api, cf="203.0.113.99")
+    assert refused.status_code == 429
+    assert "capacity" in refused.json()["detail"].lower()
+    assert refused.headers.get("retry-after")
+
+
+def test_traffic_below_the_ceiling_is_untouched(api):
+    codes = [_get(api, cf=f"203.0.113.{i}").status_code for i in range(5)]
+    assert codes == [200] * 5
+
+
+def test_the_container_healthcheck_is_exempt(api):
+    """The healthcheck runs `curl http://localhost:80/api/data-info` inside the
+    container. If the ceiling could starve it, saturation would fail the
+    healthcheck, restart the container, and turn a load spike into an outage
+    loop — the ceiling has to protect the origin, not kill it.
+    """
+    from backend.app import exempt_from_ceiling
+
+    assert exempt_from_ceiling(_ceiling_req("/api/data-info", "127.0.0.1"))
+    assert exempt_from_ceiling(_ceiling_req("/api/data-info", "::1"))
+    # Everyone else is counted.
+    assert not exempt_from_ceiling(_ceiling_req("/api/data-info", "10.0.0.9"))
+
+
+def test_the_ceiling_ignores_non_api_paths():
+    # Sitemaps and robots.txt are served by this app too, and a crawler
+    # fetching them must not be refused because the API is busy.
+    from backend.app import exempt_from_ceiling
+
+    assert exempt_from_ceiling(_ceiling_req("/sitemap.xml", "10.0.0.9"))
+    assert exempt_from_ceiling(_ceiling_req("/robots.txt", "10.0.0.9"))

backend/tests/test_suggest.py

@@ -0,0 +1,157 @@
+"""Tests for school autosuggest (spec 2026-08-26)."""
+
+from backend import data_loader
+
+
+class _FakeDocs:
+    def __init__(self, hits, explode=False):
+        self._hits = hits
+        self._explode = explode
+        self.last_params = None
+
+    def search(self, params):
+        self.last_params = params
+        if self._explode:
+            raise RuntimeError("typesense is down")
+        return {"hits": [{"document": d} for d in self._hits]}
+
+
+class _FakeClient:
+    def __init__(self, hits, explode=False):
+        self.docs = _FakeDocs(hits, explode)
+        self.collections = {"schools": type("C", (), {"documents": self.docs})()}
+
+
+_HIT = {
+    "urn": 100010, "school_name": "Brecknock Primary School",
+    "local_authority": "Camden", "postcode": "NW1 1AA",
+    "phase": "Primary", "school_type": "Community school",
+}
+
+
+def _use(monkeypatch, client):
+    monkeypatch.setattr(data_loader, "_get_typesense_client", lambda: client)
+
+
+def test_returns_the_fields_a_suggestion_needs(monkeypatch):
+    # Local authority is not decoration: there are many schools called
+    # "St Mary's", and a list without it cannot be chosen between.
+    _use(monkeypatch, _FakeClient([_HIT]))
+    out = data_loader.suggest_schools_typesense("breck")
+    assert out == [{
+        "urn": 100010, "school_name": "Brecknock Primary School",
+        "local_authority": "Camden", "postcode": "NW1 1AA",
+        "phase": "Primary", "school_type": "Community school",
+    }]
+
+
+def test_a_missing_optional_field_becomes_an_empty_string(monkeypatch):
+    # phase and school_type are optional in the Typesense schema. A missing
+    # key must not KeyError in the keystroke path.
+    _use(monkeypatch, _FakeClient([{"urn": 1, "school_name": "X",
+                                    "local_authority": "Y", "postcode": "Z"}]))
+    out = data_loader.suggest_schools_typesense("x")
+    assert out[0]["phase"] == "" and out[0]["school_type"] == ""
+
+
+def test_typesense_unavailable_gives_no_suggestions_rather_than_raising(monkeypatch):
+    _use(monkeypatch, None)
+    assert data_loader.suggest_schools_typesense("anything") == []
+
+
+def test_a_typesense_error_gives_no_suggestions_rather_than_raising(monkeypatch):
+    _use(monkeypatch, _FakeClient([], explode=True))
+    assert data_loader.suggest_schools_typesense("anything") == []
+
+
+def test_the_limit_is_passed_through_and_clamped(monkeypatch):
+    client = _FakeClient([])
+    _use(monkeypatch, client)
+    data_loader.suggest_schools_typesense("x", limit=500)
+    assert client.docs.last_params["per_page"] == 20
+
+
+def _client(monkeypatch, rows, *, blow_up_dataframe=False):
+    from fastapi.testclient import TestClient
+    from backend import app as app_module
+
+    monkeypatch.setattr(app_module, "suggest_schools_typesense",
+                        lambda q, limit=8: rows)
+    if blow_up_dataframe:
+        def _boom():
+            raise AssertionError("the suggest path must not load the DataFrame")
+        monkeypatch.setattr(app_module, "load_school_data", _boom)
+        monkeypatch.setattr(app_module, "load_latest_school_data", _boom)
+    return TestClient(app_module.app, raise_server_exceptions=False)
+
+
+def test_the_endpoint_returns_suggestions(monkeypatch):
+    body = _client(monkeypatch, [_HIT]).get("/api/suggest?q=breck").json()
+    assert body["suggestions"][0]["school_name"] == "Brecknock Primary School"
+
+
+def test_the_endpoint_never_touches_the_dataframe(monkeypatch):
+    """The whole reason this is not a mode of /api/schools.
+
+    That endpoint filters and sorts 25,000 rows of pandas per query, holding
+    the GIL. Per keystroke, that is the cost this endpoint exists to avoid.
+    """
+    res = _client(monkeypatch, [_HIT], blow_up_dataframe=True).get("/api/suggest?q=breck")
+    assert res.status_code == 200
+    assert res.json()["suggestions"]
+
+
+def test_a_one_character_query_returns_nothing_and_does_not_error(monkeypatch):
+    # The keystroke path never errors on ordinary input.
+    res = _client(monkeypatch, [_HIT]).get("/api/suggest?q=b")
+    assert res.status_code == 200
+    assert res.json() == {"suggestions": []}
+
+
+def test_a_blank_query_returns_nothing_and_does_not_error(monkeypatch):
+    res = _client(monkeypatch, [_HIT]).get("/api/suggest?q=")
+    assert res.status_code == 200
+    assert res.json() == {"suggestions": []}
+
+
+def test_typesense_down_is_an_empty_list_not_a_500(monkeypatch):
+    res = _client(monkeypatch, []).get("/api/suggest?q=breck")
+    assert res.status_code == 200
+    assert res.json() == {"suggestions": []}
+
+
+def test_the_response_is_cacheable(monkeypatch):
+    # Prefix queries repeat enormously across users, and school names change
+    # once a year. Without this the endpoint pays full price every keystroke.
+    res = _client(monkeypatch, [_HIT]).get("/api/suggest?q=breck")
+    assert "s-maxage" in res.headers.get("cache-control", "")
+    assert res.headers.get("etag")
+
+
+def test_a_malformed_urn_does_not_raise(monkeypatch):
+    """The docstring promises "never raises"; the parsing loop sat outside the
+    try, so int(None) or int("abc") would have turned a keystroke into a 500.
+
+    Typesense declares urn as int32, so this should be unreachable — but the
+    contract is what the caller relies on, and a search index is a separate
+    system that can be reindexed by something other than this code.
+    """
+    _use(monkeypatch, _FakeClient([{"urn": None, "school_name": "X",
+                                    "local_authority": "Y", "postcode": "Z"}]))
+    assert data_loader.suggest_schools_typesense("x") == []
+
+
+def test_a_malformed_row_does_not_discard_the_good_ones(monkeypatch):
+    # One bad document must not blank the whole dropdown.
+    _use(monkeypatch, _FakeClient([
+        {"urn": "not-a-number", "school_name": "Bad", "local_authority": "Y",
+         "postcode": "Z"},
+        _HIT,
+    ]))
+    out = data_loader.suggest_schools_typesense("x")
+    assert [r["urn"] for r in out] == [100010]
+
+
+def test_a_hit_with_no_document_does_not_raise(monkeypatch):
+    _use(monkeypatch, _FakeClient([{}]))
+    assert data_loader.suggest_schools_typesense("x") == []

docs/DEPLOY.md

@@ -151,6 +151,36 @@ needed), and fails the check only when a finding is rated
 **severe** (would break prod, leak data, or corrupt data). Minor findings are
 informational and never block a merge.
 
+## Rate limiting, and the Cloudflare gap
+
+Two independent limits protect the API:
+
+- **Per client**, via slowapi, keyed on `CF-Connecting-IP` (falling back to
+  `X-Forwarded-For`, then the peer address). 60/minute by default;
+  `/api/suggest` gets 120/minute because typing is bursty.
+- **Globally**, via `GlobalRateLimitMiddleware`: a fixed 60-second window over
+  all `/api/` traffic, `GLOBAL_RATE_LIMIT_PER_MINUTE` (default 3000),
+  independent of any client identity. Requests from `127.0.0.1` are exempt so
+  the container healthcheck cannot be starved into a restart loop.
+
+### Open: the origin must only accept Cloudflare
+
+`CF-Connecting-IP` is only meaningful for requests that actually reached the
+origin through Cloudflare, and **the application cannot verify that they did**.
+Anything able to reach the origin directly can set that header freely and, by
+rotating it, mint a fresh rate-limit bucket per request — defeating per-client
+limits on every endpoint.
+
+The global ceiling bounds the damage to total origin capacity. It does not fix
+the underlying gap, and nothing in the code can. Closing it needs one of:
+
+- **Authenticated Origin Pulls** — Cloudflare presents a client certificate the
+  origin requires, so non-Cloudflare traffic is refused at TLS.
+- **An origin firewall** restricted to Cloudflare's published IP ranges.
+
+Until one is in place, treat per-client limits as protection against accidents
+and ordinary load, not against a determined caller.
+
 ## Feature flags (Unleash)
 
 Flag state lives in a self-hosted Unleash instance, deployed as its own

docs/superpowers/specs/2026-08-26-school-autosuggest-design.md

@@ -0,0 +1,294 @@
+# School Autosuggest — Design
+
+**Date:** 2026-08-26
+**Status:** approved for planning
+**Depends on:** the feature-flag layer (PR #125, merged)
+
+## Goal
+
+Suggest schools by name as someone types in the site's main search box, so a
+parent who knows the school they want reaches it in one step instead of
+searching, scanning a result list, and clicking.
+
+Scope is **schools only**. Places and postcodes were considered and excluded —
+see *Out of scope*.
+
+## The finding that shapes everything
+
+The site's rate limiter does not do what it looks like it does.
+
+`limiter = Limiter(key_func=get_remote_address)` with `60/minute` reads
+`request.client.host`. In staging and production the backend has no published
+ports and sits on the internal `backend` network, so its only caller is the
+Next proxy — and `request.client.host` is therefore **the Next container**, for
+every browser user on the site.
+
+Measured against staging: 70 concurrent requests to `/api/schools` returned
+**60 × 200 and 10 × 429**. One machine consumed the whole site's budget for
+that minute.
+
+Autosuggest is the worst possible feature to build on that. One person typing
+"st marys primary" produces six to eight debounced requests; **eight concurrent
+searchers would 429 the site.** The compare modal's search-as-you-type already
+shares this bucket, so the exposure exists today — autosuggest makes it
+certain.
+
+Fixing the keying is therefore part of this work, not a follow-up.
+
+## 1. Rate-limit keying
+
+Both environments sit behind Cloudflare (`server: cloudflare`, `cf-ray` present
+on staging and production). Cloudflare sets `CF-Connecting-IP` on every request
+to the origin and **overwrites any client-supplied value**, which makes it
+trustworthy in a way a parsed `X-Forwarded-For` chain is not.
+
+```python
+def client_key(request: Request) -> str:
+    """Rate-limit bucket: the real caller, not the proxy in front of them."""
+    cf = request.headers.get("cf-connecting-ip")
+    if cf:
+        return cf.strip()
+    xff = request.headers.get("x-forwarded-for")
+    if xff:
+        return xff.split(",")[0].strip()
+    return get_remote_address(request)
+```
+
+`nextjs-app/app/api/[...path]/route.ts` already forwards every inbound header
+except `host` and `connection`, so `CF-Connecting-IP` reaches the backend with
+no proxy change.
+
+**This header is trustworthy only for traffic that actually passed through
+Cloudflare, and nothing in the application can verify that it did.** An earlier
+draft of this section claimed Cloudflare "replaces the header, so a browser
+cannot forge it", and that only the `X-Forwarded-For` fallback was forgeable.
+That was wrong. Cloudflare does overwrite the header *on requests it handles* —
+but a caller reaching the origin directly sets whatever it likes, and this
+process cannot distinguish an edge-set header from an attacker-set one. Both
+headers are equally forgeable in that scenario.
+
+The consequence is sharper than a weakened defence. An attacker rotating
+`CF-Connecting-IP` per request mints a fresh rate-limit bucket every time and
+evades per-client limits entirely — including on the DataFrame-heavy
+`/api/schools`. Against abuse that is *worse* than the shared bucket it
+replaced, which at least capped everyone at 60/minute together.
+
+Two mitigations, and they are not interchangeable:
+
+1. **The real fix is at Cloudflare** — Authenticated Origin Pulls, or an origin
+   firewall that refuses connections not from Cloudflare's ranges. Only the
+   edge can vouch for its own header. This is infrastructure work and is not
+   part of this change; it is the thing that makes the header mean anything.
+2. **The ceiling in §1.1 bounds what evading the keying can achieve** while
+   that remains open. It does not make the header trustworthy — it makes
+   trusting it survivable.
+
+The backend being unreachable from outside the Docker network is a real second
+layer, but it depends on the ingress path in front of the frontend, which this
+design does not control and should not assume.
+
+### 1.1 The ceiling, which is back
+
+The shared bucket was acting as an accidental global throttle on a
+single-process uvicorn backend that filters a 25,000-row DataFrame in-process.
+Correct per-user keying removes it: the origin becomes reachable at 60/min *per
+user* rather than 60/min in total, and — per above — at an unbounded rate by
+anyone willing to rotate a header.
+
+An earlier draft dropped the in-app ceiling, arguing it belonged at Cloudflare.
+That argument assumed the keying was sound. It is not, so the ceiling is
+load-bearing rather than redundant, and it ships here:
+
+`GlobalRateLimitMiddleware` counts all `/api/` requests in a fixed 60-second
+window against `global_rate_limit_per_minute` (3000), independent of any client
+identity, and refuses with a 429 that names capacity rather than the client —
+an operator has to be able to tell "one noisy client" from "the origin is
+saturated". It is registered last so it is outermost: a ceiling that applies
+after the expensive work has run is not a ceiling.
+
+slowapi cannot express this. `default_limits` and `application_limits` are both
+evaluated with the same `key_func`, making them per-client rather than global,
+and `application_limits` only apply with `SlowAPIMiddleware` installed, which
+this app does not use. Hence the explicit middleware — about thirty lines, and
+obviously correct, which is what a backstop needs to be.
+
+Requests from `127.0.0.1` are exempt. The container healthcheck runs
+`curl http://localhost:80/api/data-info` from inside the container, and
+starving it would fail the check, restart the container, and turn a load spike
+into an outage loop. The exemption keys on the peer address, never the `Host`
+header, which the caller sets.
+
+3000/minute is an estimate, not a measurement, and worth revisiting against
+real traffic.
+
+### Per-user limits
+
+Per-user fairness and origin protection are different jobs, and this design now
+does both separately: the ceiling above for the origin, and per-route limits
+for fairness. Conflating them is what produced the original behaviour, where
+one bucket served the whole internet.
+
+The existing 60/minute default is unchanged, and `/api/suggest` gets
+120/minute. Both are estimates rather than measurements, and are a starting
+point to revisit once the keying is correct enough for real per-user traffic to
+be visible — which it was not before, because everyone shared one bucket.
+
+## 2. `GET /api/suggest`
+
+A dedicated endpoint, not a mode of `/api/schools`.
+
+The existing search path calls Typesense for URNs and then filters, ranks and
+sorts the full in-memory DataFrame — a pandas pass per keystroke, holding the
+GIL and blocking other requests in the same worker. Suggestions need none of
+it: `urn`, `school_name`, `phase`, `school_type`, `local_authority`,
+`postcode` and `ofsted_rating` are all already in the Typesense document
+(`pipeline/scripts/sync_typesense.py`).
+
+```
+GET /api/suggest?q=<query>&limit=8
+→ 200 {"suggestions": [
+      {"urn": 100010, "school_name": "Brecknock Primary School",
+       "local_authority": "Camden", "postcode": "NW1 1AA",
+       "phase": "Primary", "school_type": "Community school"}
+  ]}
+```
+
+- **Under two characters** returns `{"suggestions": []}` with 200. The
+  keystroke path never returns an error for ordinary input.
+- **Typesense unavailable** returns `{"suggestions": []}` with 200. There is
+  deliberately **no DataFrame fallback**: the substring scan `/api/schools`
+  falls back to is precisely the cost this endpoint exists to avoid, and a
+  silent 25,000-row scan per keystroke is worse than no suggestions.
+- **`limit` is clamped** to 20. It is a public endpoint.
+- **Rate limit `120/minute`** per client, not the default 60. A 200 ms
+  debounce tops out near 5 requests/second while someone is actively typing,
+  but averages far below that across a real search; 120 leaves headroom for
+  bursts while still bounding one client.
+- **Local authority is part of the payload, not decoration.** There are many
+  schools called "St Mary's"; a suggestion list without the authority is
+  unusable for exactly the queries autosuggest is meant to serve.
+
+### Caching
+
+`CACHE_RULES` gains `("/api/suggest", (60, 3600, 86400))`. Prefix queries
+repeat enormously across users and school names change once a year.
+
+The client fetch must **not** use `cache: "no-store"`. The compare modal does,
+and copying that pattern would throw away both the browser cache and the ETag
+304s the existing `CacheAndETagMiddleware` already provides.
+
+Both environments currently report `cf-cache-status: DYNAMIC` — Cloudflare
+ignores the `Cache-Control` the API already sends, because it does not cache
+dynamic paths by default. **A Cloudflare Cache Rule for `/api/suggest*` would
+let the edge absorb most of this traffic and never reach the origin.** That is
+a dashboard change, it is optional, and nothing here depends on it.
+
+## 3. The combobox
+
+This is an ARIA combobox, not a text input with a list underneath.
+
+**Files.** `FilterBar.tsx` is already long. The work splits three ways:
+`hooks/useSchoolSuggest.ts` owns fetching, debouncing and cancellation;
+`components/SuggestList.tsx` owns rendering and ARIA; `FilterBar.tsx` wires
+them to the existing input and form.
+
+**Fetching.** 200 ms debounce; minimum two characters; an `AbortController`
+cancels the superseded request on every keystroke. Cancellation is not an
+optimisation — without it, a slow response for `"st"` can land after the fast
+one for `"st marys"` and replace a correct list with a stale one.
+
+**Suppressed during postcode entry.** The box takes a school name *or* a
+postcode, and `isValidPostcode` already distinguishes them. Suggestions do not
+appear once the value parses as a postcode.
+
+**Keyboard.** `ArrowDown`/`ArrowUp` move the active option, `Escape` closes and
+keeps the typed text, `Tab` closes. `Enter` **with an option active** navigates
+to that school's page. `Enter` **with none active** submits the free-text
+search exactly as it does today — the existing behaviour is preserved, not
+replaced.
+
+**ARIA.** `role="combobox"` with `aria-expanded` and `aria-controls` on the
+input, `aria-activedescendant` pointing at the active option, `role="listbox"`
+on the list and `role="option"` on each row.
+
+**Both instances get it.** `HomeView` renders `FilterBar` twice — hero and
+sticky — from one component, so there is one implementation.
+
+## 4. Behind a flag
+
+Flag `school_autosuggest`, declared in `backend/flags.py`, default off.
+
+This is the most-used control on the site and the first change to it in a
+while. `app/page.tsx` is an async server component, so it reads the flag and
+threads it to `FilterBar` through `HomeView` — two prop hops, explicit, no
+client-side flag read.
+
+Off means the input behaves exactly as it does today: no listener, no fetch, no
+markup. Not a rendered-then-hidden dropdown.
+
+The rate-limit keying is **not** flagged. It is a correctness fix that should
+apply whether or not autosuggest is on, and flagging it would mean shipping a
+known-wrong limiter into production deliberately.
+
+## 5. Analytics
+
+`search_submitted` already carries `via: 'input'`. Selecting a suggestion fires
+it with `via: 'suggestion'` plus the chosen `urn`, so the obvious question —
+does this actually help, or do people ignore it — has an answer in the data
+rather than an opinion.
+
+## 6. Testing
+
+**Backend.** `client_key` prefers `CF-Connecting-IP`, falls back through
+`X-Forwarded-For` to the remote address, and two different values get two
+different buckets. `/api/suggest` returns matches, returns empty below two
+characters, returns empty and 200 when Typesense is unavailable, and clamps
+`limit`. That it never touches the DataFrame is asserted by making
+`load_school_data` raise and requiring the endpoint to answer anyway.
+
+**Frontend.** The hook debounces, aborts superseded requests, and drops a
+late-arriving response for a stale query. The list renders the ARIA
+attributes. Keyboard navigation moves the active option; `Enter` on an option
+navigates; `Enter` on none submits the search.
+
+**E2E.** With the flag on, typing a known school name shows it and selecting it
+lands on that school's page. With the flag off, no combobox markup exists.
+Gated on the flag the same way the distance journeys are — read the observable
+effect, since `/api/flags` is denied to the public.
+
+## 7. Risks
+
+**Removing the accidental throttle.** Covered in §1. Correct per-user keying
+means the origin is reachable at 60/minute *per user* where it was 60/minute
+in total, and no in-app global cap replaces it — that job goes to Cloudflare,
+which is not done as part of this change. Until it is, a determined caller
+with many source addresses can put more load on a single-process origin than
+they can today. Against this site's traffic that is a theoretical risk rather
+than a live one, but it is a real one and it is the price of the fix.
+
+**Cloudflare bypass — the open one.** If the origin is reachable without
+passing through Cloudflare, `CF-Connecting-IP` is attacker-controlled, and
+rotating it per request defeats per-client limits on every endpoint. The
+ceiling in §1.1 bounds the damage to the origin's total capacity; it does not
+restore per-client fairness under attack, and it cannot. Closing this properly
+means Authenticated Origin Pulls or an origin firewall restricted to
+Cloudflare's published ranges — infrastructure work, outside this change, and
+the single most valuable follow-up here.
+
+**Typesense becomes user-visible.** Today a Typesense outage degrades search to
+a slow substring match. With autosuggest it also means the dropdown silently
+stops appearing. That is the correct failure — quiet, not broken — but it makes
+Typesense health worth monitoring in a way it was not before.
+
+## Out of scope
+
+- **Place suggestions.** The 2,646 town, authority and outcode pages are a
+  strong candidate and would route people onto the pages W2 built, but they
+  live in the place registry rather than Typesense, so it is a second index and
+  a ranking rule for comparing two kinds of result. Worth its own change.
+- **Postcode completion.** Would put postcodes.io in the keystroke path, with
+  its own latency and rate limits.
+- **The compare modal.** It already has search-as-you-type. Converting it to
+  this component is a reasonable follow-up, not part of this.
+- **Recent or popular searches.** No storage for either, and no evidence yet
+  that they are wanted.

e2e/tests/journeys.spec.ts

@@ -2111,3 +2111,66 @@ test('the rankings page still orders by score, not name', async ({ page }) => {
     .filter((v: number | null) => v != null);
   expect(scores).toEqual([...scores].sort((a: number, b: number) => b - a));
 });
+
+/*
+ * School autosuggest (spec 2026-08-26).
+ */
+async function autosuggestIsOn(page: Page): Promise<boolean> {
+  await page.goto('/');
+  return (await page.getByRole('combobox').count()) > 0;
+}
+
+test('the suggest endpoint answers from Typesense', async ({ page }) => {
+  // Not flagged — the endpoint is live even while the UI is dark, so it can
+  // be smoke-tested before the feature is switched on.
+  const res = await page.request.get('/api/suggest?q=brecknock');
+  expect(res.ok()).toBeTruthy();
+  const { suggestions } = await res.json();
+  expect(Array.isArray(suggestions)).toBeTruthy();
+  if (suggestions.length) {
+    // Local authority is what tells two "St Mary's" apart.
+    expect(suggestions[0]).toHaveProperty('school_name');
+    expect(suggestions[0]).toHaveProperty('local_authority');
+  }
+});
+
+test('a one-character query is answered, not rejected', async ({ page }) => {
+  // The keystroke path never errors on ordinary input.
+  const res = await page.request.get('/api/suggest?q=b');
+  expect(res.status()).toBe(200);
+  expect((await res.json()).suggestions).toEqual([]);
+});
+
+test('the suggest response is cacheable', async ({ page }) => {
+  const res = await page.request.get('/api/suggest?q=brecknock');
+  expect(res.headers()['cache-control'] ?? '').toContain('s-maxage');
+});
+
+test('typing a school name suggests it, and choosing it opens that school', async ({ page }) => {
+  test.skip(!(await autosuggestIsOn(page)),
+    'the school_autosuggest flag is off in this environment');
+
+  // A school certain to exist in any environment with data.
+  const { schools } = await (await page.request.get('/api/schools?page_size=1')).json();
+  test.skip(!schools?.length, 'no schools in this environment');
+  const name = schools[0].school_name as string;
+
+  await page.goto('/');
+  await page.getByRole('combobox').first().fill(name.slice(0, 12));
+  const option = page.getByRole('option').first();
+  await expect(option).toBeVisible();
+  await option.click();
+  await expect(page).toHaveURL(/\/school\/\d+/);
+});
+
+test('with autosuggest off, the search box is a plain input', async ({ page }) => {
+  test.skip(await autosuggestIsOn(page),
+    'the school_autosuggest flag is on in this environment');
+
+  await page.goto('/');
+  await expect(page.getByRole('combobox')).toHaveCount(0);
+  // And the box still works: the existing search must be untouched.
+  await page.getByPlaceholder(/School name or postcode/i).first().fill('abbey');
+  await page.getByRole('button', { name: /Search/i }).first().click();
+  await expect(page).toHaveURL(/search=abbey/);
+});

nextjs-app/__tests__/components/FilterBarSuggest.test.tsx

@@ -0,0 +1,76 @@
+import { render, screen, fireEvent, waitFor } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import { FilterBar } from '@/components/FilterBar';
+
+const push = jest.fn();
+jest.mock('next/navigation', () => ({
+  useRouter: () => ({ push, replace: jest.fn(), prefetch: jest.fn() }),
+  usePathname: () => '/',
+  useSearchParams: () => new URLSearchParams(),
+}));
+
+const FILTERS = {
+  local_authorities: [], school_types: [], years: [], phases: [],
+  genders: [], admissions_policies: [],
+};
+
+const realFetch = global.fetch;
+beforeEach(() => {
+  global.fetch = jest.fn(async () => ({
+    ok: true,
+    json: async () => ({ suggestions: [{
+      urn: 100010, school_name: 'Brecknock Primary School',
+      local_authority: 'Camden', postcode: 'NW1 1AA',
+      phase: 'Primary', school_type: 'Community school' }] }),
+  })) as unknown as typeof fetch;
+  push.mockClear();
+});
+afterEach(() => { global.fetch = realFetch; });
+
+describe('FilterBar autosuggest', () => {
+  it('is a combobox only when the flag is on', () => {
+    const { rerender } = render(<FilterBar filters={FILTERS} autosuggest={false} />);
+    expect(screen.queryByRole('combobox')).not.toBeInTheDocument();
+    rerender(<FilterBar filters={FILTERS} autosuggest />);
+    expect(screen.getByRole('combobox')).toBeInTheDocument();
+  });
+
+  it('makes no request while the flag is off', async () => {
+    // Off means off: no listener, no fetch, no markup.
+    render(<FilterBar filters={FILTERS} autosuggest={false} />);
+    await userEvent.type(screen.getByPlaceholderText(/School name or postcode/i),
+      'brecknock');
+    expect(global.fetch).not.toHaveBeenCalled();
+  });
+
+  it('shows suggestions and navigates when one is chosen', async () => {
+    render(<FilterBar filters={FILTERS} autosuggest />);
+    await userEvent.type(screen.getByRole('combobox'), 'brecknock');
+    const option = await screen.findByRole('option', { name: /Brecknock/ });
+    await userEvent.click(option);
+    expect(push).toHaveBeenCalledWith(
+      expect.stringContaining('/school/100010'));
+  });
+
+  it('suppresses suggestions once the value is a postcode', async () => {
+    // The box takes a name OR a postcode; suggestions must get out of the way.
+    //
+    // fireEvent.change, not userEvent.type: typing sets "N", "NW", "NW1"... and
+    // "NW1" is not a postcode, so a request for it is correct behaviour. Only
+    // the settled value is the assertion, so set it in one go.
+    render(<FilterBar filters={FILTERS} autosuggest />);
+    fireEvent.change(screen.getByRole('combobox'), { target: { value: 'NW1 1AA' } });
+    await new Promise((r) => setTimeout(r, 300));   // past the 200ms debounce
+    expect(global.fetch).not.toHaveBeenCalled();
+  });
+
+  it('Enter with no active option still submits the free-text search', async () => {
+    // The existing behaviour is preserved, not replaced.
+    render(<FilterBar filters={FILTERS} autosuggest />);
+    const input = screen.getByRole('combobox');
+    await userEvent.type(input, 'brecknock{Enter}');
+    // updateURL pushes inside startTransition, so the call is not synchronous.
+    await waitFor(() => expect(push).toHaveBeenCalledWith(
+      expect.stringContaining('search=brecknock')));
+  });
+});

nextjs-app/__tests__/components/SuggestList.test.tsx

@@ -0,0 +1,50 @@
+import { render, screen } from '@testing-library/react';
+import { SuggestList, suggestOptionId } from '@/components/SuggestList';
+
+const ROWS = [
+  { urn: 1, school_name: "St Mary's Primary", local_authority: 'Camden',
+    postcode: 'NW1 1AA', phase: 'Primary', school_type: 'Voluntary aided school' },
+  { urn: 2, school_name: "St Mary's Primary", local_authority: 'Barnet',
+    postcode: 'EN5 2AA', phase: 'Primary', school_type: 'Community school' },
+];
+
+describe('SuggestList', () => {
+  it('is a listbox of options', () => {
+    render(<SuggestList id="s" suggestions={ROWS} activeIndex={-1}
+      onPick={() => {}} onHover={() => {}} />);
+    expect(screen.getByRole('listbox')).toBeInTheDocument();
+    expect(screen.getAllByRole('option')).toHaveLength(2);
+  });
+
+  it('shows the local authority, which is what tells two schools apart', () => {
+    // Both rows are "St Mary's Primary". Without the authority the list is
+    // unusable for exactly the query autosuggest exists to serve.
+    render(<SuggestList id="s" suggestions={ROWS} activeIndex={-1}
+      onPick={() => {}} onHover={() => {}} />);
+    expect(screen.getByText('Camden')).toBeInTheDocument();
+    expect(screen.getByText('Barnet')).toBeInTheDocument();
+  });
+
+  it('marks only the active option selected', () => {
+    render(<SuggestList id="s" suggestions={ROWS} activeIndex={1}
+      onPick={() => {}} onHover={() => {}} />);
+    const options = screen.getAllByRole('option');
+    expect(options[0]).toHaveAttribute('aria-selected', 'false');
+    expect(options[1]).toHaveAttribute('aria-selected', 'true');
+  });
+
+  it('gives each option the id the input will point at', () => {
+    // aria-activedescendant on the input has to name a real element id, or
+    // a screen reader announces nothing as the user arrows through.
+    render(<SuggestList id="s" suggestions={ROWS} activeIndex={0}
+      onPick={() => {}} onHover={() => {}} />);
+    expect(screen.getAllByRole('option')[0]).toHaveAttribute(
+      'id', suggestOptionId('s', 0));
+  });
+
+  it('renders nothing when there is nothing to suggest', () => {
+    const { container } = render(<SuggestList id="s" suggestions={[]}
+      activeIndex={-1} onPick={() => {}} onHover={() => {}} />);
+    expect(container).toBeEmptyDOMElement();
+  });
+});

nextjs-app/__tests__/components/darkThemeSafety.test.ts

@@ -0,0 +1,78 @@
+import fs from 'fs';
+import path from 'path';
+
+/**
+ * Guards against light-theme-only CSS.
+ *
+ * The site themes entirely through tokens redefined under
+ * `@media (prefers-color-scheme: dark)`. A hardcoded colour therefore does not
+ * fail loudly — it renders perfectly in the theme it was written for and
+ * quietly wrongly in the other, which nobody sees unless they happen to be in
+ * dark mode when they look.
+ *
+ * Both rules below are drawn from real defects in SchoolHeroMap.module.css,
+ * found by eye rather than by any test:
+ *
+ *  - the map's fade to the header ramped through hardcoded white and landed on
+ *    `var(--bg-card)`. Invisible in light; a bright band across the full width
+ *    of a near-black card in dark.
+ *  - the controls floating over the map paired a hardcoded white background
+ *    with `color: var(--text-primary)`, which resolves to #E9EEF0 in dark —
+ *    near-white text on a near-white button.
+ */
+
+const COMPONENTS = path.join(__dirname, '..', '..', 'components');
+
+function stylesheets(dir: string): string[] {
+  return fs.readdirSync(dir, { withFileTypes: true }).flatMap((entry) => {
+    const full = path.join(dir, entry.name);
+    if (entry.isDirectory()) return stylesheets(full);
+    return entry.name.endsWith('.module.css') ? [full] : [];
+  });
+}
+
+/** Innermost `selector { body }` pairs. Nested at-rules never match as rules,
+ *  because their body contains braces. */
+function rules(css: string): Array<{ selector: string; body: string }> {
+  return Array.from(css.matchAll(/([^{}]+)\{([^{}]*)\}/g), (m) => ({
+    selector: m[1].trim().split('\n').pop()!.trim(),
+    body: m[2],
+  }));
+}
+
+const HARDCODED_WHITE_BG = /background[^;]*(?:255,\s*255,\s*255|#fff\b|#ffffff\b)/i;
+const THEMED_COLOR = /(?:^|[^-])color:\s*var\(--/;
+
+const files = stylesheets(COMPONENTS);
+
+describe('dark-theme safety', () => {
+  it('finds stylesheets to check', () => {
+    expect(files.length).toBeGreaterThan(0);
+  });
+
+  it('never pairs a hardcoded white background with a themed text colour', () => {
+    const offenders = files.flatMap((file) =>
+      rules(fs.readFileSync(file, 'utf8'))
+        .filter((r) => HARDCODED_WHITE_BG.test(r.body) && THEMED_COLOR.test(r.body))
+        .map((r) => `${path.relative(COMPONENTS, file)}  ${r.selector}`));
+
+    // Either the surface follows the theme and so should the text, or it does
+    // not and the text must be literal too. Mixing them is how near-white text
+    // ends up on a near-white button.
+    expect(offenders).toEqual([]);
+  });
+
+  it('never fades to a themed colour through a hardcoded one', () => {
+    const offenders = files.flatMap((file) =>
+      rules(fs.readFileSync(file, 'utf8'))
+        .filter((r) => /linear-gradient/.test(r.body)
+          && /var\(--bg-(card|primary|secondary)\)/.test(r.body)
+          && /255,\s*255,\s*255|#fff\b/i.test(r.body))
+        .map((r) => `${path.relative(COMPONENTS, file)}  ${r.selector}`));
+
+    // A gradient that lands on a token has to be made of that token, or the
+    // ramp and its destination disagree in one theme. Use the matching
+    // `--*-rgb` token for the transparent stops.
+    expect(offenders).toEqual([]);
+  });
+});

nextjs-app/__tests__/hooks/useSchoolSuggest.test.tsx

@@ -0,0 +1,73 @@
+import { renderHook, act, waitFor } from '@testing-library/react';
+import { useSchoolSuggest } from '@/hooks/useSchoolSuggest';
+
+const realFetch = global.fetch;
+
+function mockFetch(rows: unknown[], delayMs = 0) {
+  global.fetch = jest.fn(async (_url: unknown, init?: { signal?: AbortSignal }) => {
+    if (delayMs) {
+      await new Promise((resolve, reject) => {
+        const t = setTimeout(resolve, delayMs);
+        init?.signal?.addEventListener('abort', () => {
+          clearTimeout(t);
+          reject(Object.assign(new Error('aborted'), { name: 'AbortError' }));
+        });
+      });
+    }
+    return { ok: true, json: async () => ({ suggestions: rows }) };
+  }) as unknown as typeof fetch;
+}
+
+const ROW = {
+  urn: 1, school_name: 'Brecknock Primary School', local_authority: 'Camden',
+  postcode: 'NW1 1AA', phase: 'Primary', school_type: 'Community school',
+};
+
+describe('useSchoolSuggest', () => {
+  beforeEach(() => { jest.useFakeTimers(); });
+  afterEach(() => { jest.useRealTimers(); global.fetch = realFetch; });
+
+  it('does not fetch below the minimum query length', () => {
+    mockFetch([ROW]);
+    renderHook(() => useSchoolSuggest('b', true));
+    act(() => { jest.advanceTimersByTime(500); });
+    expect(global.fetch).not.toHaveBeenCalled();
+  });
+
+  it('does not fetch at all when disabled', () => {
+    // The flag being off must mean no request, not a hidden dropdown.
+    mockFetch([ROW]);
+    renderHook(() => useSchoolSuggest('brecknock', false));
+    act(() => { jest.advanceTimersByTime(500); });
+    expect(global.fetch).not.toHaveBeenCalled();
+  });
+
+  it('debounces rather than firing per keystroke', () => {
+    mockFetch([ROW]);
+    const { rerender } = renderHook(
+      ({ q }) => useSchoolSuggest(q, true), { initialProps: { q: 'br' } });
+    rerender({ q: 'bre' });
+    rerender({ q: 'brec' });
+    act(() => { jest.advanceTimersByTime(199); });
+    expect(global.fetch).not.toHaveBeenCalled();
+    act(() => { jest.advanceTimersByTime(2); });
+    expect(global.fetch).toHaveBeenCalledTimes(1);
+  });
+
+  it('opens with results once they arrive', async () => {
+    mockFetch([ROW]);
+    const { result } = renderHook(() => useSchoolSuggest('brecknock', true));
+    act(() => { jest.advanceTimersByTime(200); });
+    await waitFor(() => expect(result.current.suggestions).toHaveLength(1));
+    expect(result.current.open).toBe(true);
+  });
+
+  it('close() hides the list without clearing the query', async () => {
+    mockFetch([ROW]);
+    const { result } = renderHook(() => useSchoolSuggest('brecknock', true));
+    act(() => { jest.advanceTimersByTime(200); });
+    await waitFor(() => expect(result.current.open).toBe(true));
+    act(() => { result.current.close(); });
+    expect(result.current.open).toBe(false);
+  });
+});

nextjs-app/app/globals.css

@@ -28,6 +28,9 @@
     --bg-primary: #FAFAF8;      /* Warm White */
     --bg-secondary: #F5EFE6;    /* Sand — hero panels, sunken rows */
     --bg-card: #FFFFFF;
+    /* For gradients that have to fade to the card colour. A hardcoded white
+       ramp reads as a bright band against a dark card. */
+    --bg-card-rgb: 255, 255, 255;
     --surface-inverse: #0F766E;
 
     /* ── Ink ────────────────────────────────────────────────────────── */
@@ -234,6 +237,7 @@
         --bg-primary: #111A20;
         --bg-secondary: #16222A;
         --bg-card: #18242C;
+        --bg-card-rgb: 24, 36, 44;
         --surface-inverse: #E9EEF0;
 
         --text-primary: #E9EEF0;

nextjs-app/app/page.tsx

@@ -8,6 +8,7 @@ import type { Metadata } from 'next';
 import { fetchSchools, fetchFilters, fetchDataInfo } from '@/lib/api';
 import { formatAcademicYear } from '@/lib/utils';
 import { HomeView } from '@/components/HomeView';
+import { getFlags } from '@/lib/flags';
 import { HowItWorksSection } from '@/components/HowItWorksSection';
 import { EditorialSection } from '@/components/EditorialSection';
 
@@ -63,6 +64,11 @@ export default async function HomePage({ searchParams }: HomePageProps) {
   // Await search params (Next.js 15 requirement)
   const params = await searchParams;
 
+  // Server-read: no flag value reaches the browser bundle. Threaded down to
+  // both FilterBar instances via HomeView.
+  const flags = await getFlags();
+  const autosuggest = flags.school_autosuggest === true;
+
   // Parse search params
   const page = parseInt(params.page || '1');
   const radius = params.radius ? parseFloat(params.radius) : undefined;
@@ -111,6 +117,7 @@ export default async function HomePage({ searchParams }: HomePageProps) {
     const years = dataInfo?.years_available ?? [];
     return (
       <HomeView
+        autosuggest={autosuggest}
         initialSchools={schoolsData}
         filters={resolvedFilters}
         totalSchools={total}
@@ -131,6 +138,7 @@ export default async function HomePage({ searchParams }: HomePageProps) {
     const emptyFilters = { local_authorities: [], school_types: [], years: [], phases: [], genders: [], admissions_policies: [] };
     return (
       <HomeView
+        autosuggest={autosuggest}
         initialSchools={{ schools: [], page: 1, page_size: 50, total: 0, total_pages: 0 }}
         filters={emptyFilters}
         totalSchools={null}

nextjs-app/components/FilterBar.module.css

@@ -48,6 +48,8 @@
   display: flex;
   align-items: center;
   gap: 0.5rem;
+  /* The suggestion dropdown is absolutely positioned against this box. */
+  position: relative;
 }
 
 /* The hero pill: hairline, soft corner, everything else sits inside it. */

nextjs-app/components/FilterBar.tsx

@@ -3,8 +3,11 @@
 import { useState, useCallback, useTransition, useRef, useEffect } from "react";
 import type { ReactNode } from "react";
 import { useRouter, useSearchParams, usePathname } from "next/navigation";
-import { isValidPostcode } from "@/lib/utils";
+import { isValidPostcode, schoolUrl } from "@/lib/utils";
 import { track } from "@/lib/analytics";
+import { useSchoolSuggest } from "@/hooks/useSchoolSuggest";
+import { SuggestList, suggestOptionId } from "./SuggestList";
+import type { Suggestion } from "@/lib/suggest";
 import type { Filters, ResultFilters } from "@/lib/types";
 import styles from "./FilterBar.module.css";
 
@@ -17,6 +20,8 @@ interface FilterBarProps {
   onNearMe?: () => void;
   geoState?: "idle" | "requesting" | "error";
   geoError?: string | null;
+  /** Server-read feature flag. Off means no listener, no fetch, no markup. */
+  autosuggest?: boolean;
 }
 
 /**
@@ -48,6 +53,7 @@ export function FilterBar({
   onNearMe,
   geoState = "idle",
   geoError,
+  autosuggest = false,
 }: FilterBarProps) {
   const router = useRouter();
   const pathname = usePathname();
@@ -62,6 +68,45 @@ export function FilterBar({
 
   const [omniValue, setOmniValue] = useState(initialOmniValue);
 
+  const suggestId = `school-suggest-${isHero ? "hero" : "bar"}`;
+  // Suppressed once the value parses as a postcode: the box takes a school
+  // name OR a postcode, and suggesting schools during postcode entry fights
+  // the user rather than helping them.
+  const suggestEnabled = autosuggest && !isValidPostcode(omniValue);
+  const { suggestions, open, activeIndex, setActiveIndex, close } =
+    useSchoolSuggest(omniValue, suggestEnabled);
+
+  const pickSuggestion = (s: Suggestion) => {
+    close();
+    track('search_submitted', {
+      query: s.school_name.toLowerCase(),
+      via: 'suggestion',
+      urn: s.urn,
+      has_postcode: false,
+      filters_active: '',
+      filters_count: 0,
+    });
+    router.push(schoolUrl(s.urn, s.school_name));
+  };
+
+  const handleOmniKeyDown = (e: React.KeyboardEvent<HTMLInputElement>) => {
+    if (!open) return;
+    if (e.key === "ArrowDown") {
+      e.preventDefault();
+      setActiveIndex(activeIndex + 1 >= suggestions.length ? 0 : activeIndex + 1);
+    } else if (e.key === "ArrowUp") {
+      e.preventDefault();
+      setActiveIndex(activeIndex <= 0 ? suggestions.length - 1 : activeIndex - 1);
+    } else if (e.key === "Escape") {
+      close();
+    } else if (e.key === "Enter" && activeIndex >= 0) {
+      // Only when an option is active. With none, the event falls through to
+      // the form's submit handler and searches the typed text, as it does now.
+      e.preventDefault();
+      pickSuggestion(suggestions[activeIndex]);
+    }
+  };
+
   const currentLA = searchParams.get("local_authority") || "";
   const currentType = searchParams.get("school_type") || "";
   const currentPhase = searchParams.get("phase") || "";
@@ -227,8 +272,19 @@ export function FilterBar({
             type="search"
             value={omniValue}
             onChange={(e) => setOmniValue(e.target.value)}
+            onKeyDown={handleOmniKeyDown}
+            onBlur={close}
             placeholder="School name or postcode"
             className={styles.omniInput}
+            {...(autosuggest ? {
+              role: "combobox",
+              "aria-expanded": open,
+              "aria-controls": suggestId,
+              "aria-autocomplete": "list" as const,
+              "aria-activedescendant":
+                activeIndex >= 0 ? suggestOptionId(suggestId, activeIndex) : undefined,
+              autoComplete: "off",
+            } : {})}
           />
           <button
             type="submit"
@@ -237,6 +293,15 @@ export function FilterBar({
           >
             {isPending ? <div className={styles.spinner}></div> : isHero ? "Search schools" : "Search"}
           </button>
+          {autosuggest && open && (
+            <SuggestList
+              id={suggestId}
+              suggestions={suggestions}
+              activeIndex={activeIndex}
+              onPick={pickSuggestion}
+              onHover={setActiveIndex}
+            />
+          )}
         </div>
         {isHero && (
           <>

nextjs-app/components/HomeView.tsx

@@ -29,6 +29,8 @@ interface HomeViewProps {
   // show (e.g. an active search).
   howItWorks?: React.ReactNode;
   editorial?: React.ReactNode;
+  /** Server-read feature flag, threaded to both FilterBar instances. */
+  autosuggest?: boolean;
 }
 
 function daysUntil(month: number, day: number): number {
@@ -193,7 +195,7 @@ const VALUE_PROPS: ValueProp[] = [
   },
 ];
 
-export function HomeView({ initialSchools, filters, totalSchools, howItWorks, editorial }: HomeViewProps) {
+export function HomeView({ initialSchools, filters, totalSchools, howItWorks, editorial, autosuggest = false }: HomeViewProps) {
   const searchParams = useSearchParams();
   const router = useRouter();
   const pathname = usePathname();
@@ -462,6 +464,7 @@ export function HomeView({ initialSchools, filters, totalSchools, howItWorks, ed
               onNearMe={handleNearMe}
               geoState={geoState}
               geoError={geoError}
+              autosuggest={autosuggest}
             />
           </div>
 
@@ -500,6 +503,7 @@ export function HomeView({ initialSchools, filters, totalSchools, howItWorks, ed
           onNearMe={handleNearMe}
           geoState={geoState}
           geoError={geoError}
+          autosuggest={autosuggest}
         />
       )}
 

nextjs-app/components/SchoolHeroMap.module.css

@@ -47,7 +47,13 @@
     width: 100%;
     height: 100%;
     background:
-        linear-gradient(100deg, rgba(255, 255, 255, 0) 40%, rgba(255, 255, 255, .5) 50%, rgba(255, 255, 255, 0) 60%) var(--bg-secondary);
+        /* Sweeps toward the card colour, which is a shade lighter than this
+           ground in both themes. Hardcoded white was a bright flash across a
+           dark page every 1.4s while the tiles loaded. */
+        linear-gradient(100deg,
+            rgba(var(--bg-card-rgb), 0) 40%,
+            rgba(var(--bg-card-rgb), .5) 50%,
+            rgba(var(--bg-card-rgb), 0) 60%) var(--bg-secondary);
     background-size: 200% 100%;
     animation: shimmer 1.4s infinite;
 }
@@ -76,6 +82,15 @@
     justify-content: center;
 }
 
+/*
+ * Controls that float ON the map.
+ *
+ * The map tiles are light in both themes, so these deliberately do NOT follow
+ * the theme — they follow the map. The literal ink below is the point: paired
+ * with a hardcoded white background, `color: var(--text-primary)` resolved to
+ * #E9EEF0 in the dark theme and put near-white text on a near-white button.
+ * A themed token is the wrong tool for a surface that never changes.
+ */
 .openHint {
     display: inline-flex;
     align-items: center;
@@ -85,7 +100,8 @@
     border-radius: 999px;
     font-size: 13px;
     font-weight: 600;
-    color: var(--text-primary);
+    /* See "Controls that float ON the map" above. */
+    color: #1C2731;
     background: rgba(255, 255, 255, .85);
     -webkit-backdrop-filter: blur(6px);
     backdrop-filter: blur(6px);
@@ -113,11 +129,18 @@
        on top of the blend. */
     z-index: 450;
     pointer-events: none;
+    /* The card colour, not white.
+       This ramp was hardcoded white and ended at var(--bg-card). In the light
+       theme that is white into white and invisible, as intended. In the dark
+       theme it climbed to 95% WHITE and then met a near-black card — a bright
+       band across the full width, right where the map is supposed to dissolve
+       into the header. Fading to the same colour the gradient lands on is the
+       whole trick, and it only works if that colour is a token. */
     background: linear-gradient(to bottom,
-            rgba(255, 255, 255, 0) 0%,
-            rgba(255, 255, 255, .35) 35%,
-            rgba(255, 255, 255, .75) 62%,
-            rgba(255, 255, 255, .95) 82%,
+            rgba(var(--bg-card-rgb), 0) 0%,
+            rgba(var(--bg-card-rgb), .35) 35%,
+            rgba(var(--bg-card-rgb), .75) 62%,
+            rgba(var(--bg-card-rgb), .95) 82%,
             var(--bg-card) 100%);
 }
 
@@ -134,7 +157,8 @@
     border: none;
     border-radius: 8px;
     background: rgba(255, 255, 255, .92);
-    color: var(--text-primary);
+    /* See "Controls that float ON the map" above. */
+    color: #1C2731;
     cursor: pointer;
     box-shadow: 0 2px 10px rgba(var(--shadow-rgb), .2);
 }

nextjs-app/components/SuggestList.module.css

@@ -0,0 +1,53 @@
+/*
+ * Anchored to .omniBoxContainer, which is position: relative for this reason.
+ *
+ * Every colour is a token, so the dropdown follows the theme. The dark theme
+ * redefines --bg-card, --border, --text-muted and --shadow-soft, and this
+ * inherits all four without a second rule.
+ */
+.list {
+  position: absolute;
+  top: calc(100% + 4px);
+  left: 0;
+  right: 0;
+  /* Above the sticky filter bar (10) and the hero layers (0–2), below the
+     skip-link (10000) and the modal overlay (1000). */
+  z-index: 40;
+  margin: 0;
+  padding: 4px;
+  list-style: none;
+  max-height: 320px;
+  overflow-y: auto;
+  background: var(--bg-card);
+  border: 1px solid var(--border);
+  border-radius: var(--radius-md);
+  box-shadow: var(--shadow-soft);
+}
+
+.option {
+  display: flex;
+  align-items: baseline;
+  justify-content: space-between;
+  gap: 12px;
+  padding: 10px 12px;
+  border-radius: var(--radius-sm);
+  cursor: pointer;
+  color: var(--text-primary);
+}
+
+/* Hover and keyboard share one style: the active option is the active option
+   however it became active. Two rules would drift. */
+.option:hover,
+.active {
+  background: var(--bg-secondary);
+}
+
+.name {
+  font-weight: 500;
+}
+
+.meta {
+  font-size: 0.85em;
+  color: var(--text-muted);
+  white-space: nowrap;
+}

nextjs-app/components/SuggestList.tsx

@@ -0,0 +1,53 @@
+'use client';
+
+/**
+ * The autosuggest dropdown. Presentational only — it fetches nothing and owns
+ * no state, so the fetching rules and the ARIA rules can be read separately.
+ */
+
+import type { Suggestion } from '@/lib/suggest';
+import styles from './SuggestList.module.css';
+
+/** The id the input's aria-activedescendant points at. */
+export function suggestOptionId(id: string, index: number): string {
+  return `${id}-option-${index}`;
+}
+
+interface Props {
+  /** Shared with the input's aria-controls. */
+  id: string;
+  suggestions: Suggestion[];
+  activeIndex: number;
+  onPick: (s: Suggestion) => void;
+  onHover: (index: number) => void;
+}
+
+export function SuggestList({ id, suggestions, activeIndex, onPick, onHover }: Props) {
+  if (suggestions.length === 0) return null;
+
+  return (
+    <ul className={styles.list} id={id} role="listbox">
+      {suggestions.map((s, i) => (
+        <li
+          key={s.urn}
+          id={suggestOptionId(id, i)}
+          role="option"
+          aria-selected={i === activeIndex}
+          className={`${styles.option} ${i === activeIndex ? styles.active : ''}`}
+          /*
+           * onMouseDown, not onClick: the input's blur handler closes the list,
+           * and blur fires before click — so a click handler never runs. This
+           * is the classic autosuggest bug where the dropdown is unclickable
+           * with a mouse while working perfectly with a keyboard.
+           */
+          onMouseDown={(e) => { e.preventDefault(); onPick(s); }}
+          onMouseEnter={() => onHover(i)}
+        >
+          <span className={styles.name}>{s.school_name}</span>
+          {/* Not decoration: there are many "St Mary's". */}
+          <span className={styles.meta}>{s.local_authority}</span>
+        </li>
+      ))}
+    </ul>
+  );
+}

nextjs-app/hooks/useSchoolSuggest.ts

@@ -0,0 +1,58 @@
+'use client';
+
+import { useEffect, useRef, useState } from 'react';
+import { fetchSuggestions, SUGGEST_MIN_QUERY, type Suggestion } from '@/lib/suggest';
+
+/*
+ * Long enough that a fast typist does not fire a request per character, short
+ * enough that the list feels attached to the keyboard.
+ */
+const DEBOUNCE_MS = 200;
+
+export function useSchoolSuggest(query: string, enabled: boolean) {
+  const [suggestions, setSuggestions] = useState<Suggestion[]>([]);
+  const [open, setOpen] = useState(false);
+  const [activeIndex, setActiveIndex] = useState(-1);
+  // Set when the user dismisses the list, so a re-render does not reopen it.
+  const dismissed = useRef('');
+
+  useEffect(() => {
+    const q = query.trim();
+    if (!enabled || q.length < SUGGEST_MIN_QUERY || dismissed.current === q) {
+      setSuggestions([]);
+      setOpen(false);
+      return;
+    }
+
+    /*
+     * Abort the superseded request on every keystroke. This is correctness,
+     * not economy: without it a slow response for "st" can land after the fast
+     * one for "st marys" and replace a correct list with a stale one.
+     */
+    const controller = new AbortController();
+    const timer = setTimeout(async () => {
+      const rows = await fetchSuggestions(q, controller.signal);
+      if (controller.signal.aborted) return;
+      setSuggestions(rows);
+      setActiveIndex(-1);
+      setOpen(rows.length > 0);
+    }, DEBOUNCE_MS);
+
+    return () => {
+      clearTimeout(timer);
+      controller.abort();
+    };
+  }, [query, enabled]);
+
+  return {
+    suggestions,
+    open,
+    activeIndex,
+    setActiveIndex,
+    close: () => {
+      dismissed.current = query.trim();
+      setOpen(false);
+      setActiveIndex(-1);
+    },
+  };
+}

nextjs-app/lib/suggest.ts

@@ -0,0 +1,39 @@
+/**
+ * Client for /api/suggest.
+ *
+ * No `cache: "no-store"`. The compare modal's search uses it, and copying that
+ * here would discard both the browser cache and the ETag 304s the backend's
+ * CacheAndETagMiddleware already provides — on the one endpoint where prefix
+ * queries repeat most.
+ */
+
+export interface Suggestion {
+  urn: number;
+  school_name: string;
+  local_authority: string;
+  postcode: string;
+  phase: string;
+  school_type: string;
+}
+
+/** Below this the response is thousands of schools and worth no round trip. */
+export const SUGGEST_MIN_QUERY = 2;
+
+const API = process.env.NEXT_PUBLIC_API_URL || '/api';
+
+/** Suggestions for `q`. Never throws: no suggestions is a fine outcome. */
+export async function fetchSuggestions(
+  q: string, signal?: AbortSignal,
+): Promise<Suggestion[]> {
+  if (q.trim().length < SUGGEST_MIN_QUERY) return [];
+  try {
+    const res = await fetch(`${API}/suggest?q=${encodeURIComponent(q.trim())}`,
+      { signal });
+    if (!res.ok) return [];
+    const body = await res.json();
+    return body.suggestions ?? [];
+  } catch {
+    // Includes AbortError, which is the normal path on every keystroke.
+    return [];
+  }
+}