diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 047509ae..6874398d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -405,6 +405,10 @@ jobs:
             # is not; elevation is left to the public-DNS step above, which has
             # the retries for it.
             echo "CFGKEYS_B64=$(printf '%s' "$TOWER_CONTRACT_CONFIG_KEYS" | base64 | tr -d '\n')"
+            # The geocode route, also forwarded by the include. Its probe is an
+            # empty query the service refuses at validation, so it is as
+            # deterministic here as the config read.
+            echo "GEOBODY_B64=$(printf '%s' "$TOWER_CONTRACT_GEOCODE_BODY" | base64 | tr -d '\n')"
           } >> "$GITHUB_ENV"
       - name: Assert staging's instance
         if: github.event_name == 'push'
@@ -413,17 +417,19 @@ jobs:
           QUERY_B64: ${{ env.QUERY_B64 }}
           ECHO_B64: ${{ env.ECHO_B64 }}
           CFGKEYS_B64: ${{ env.CFGKEYS_B64 }}
+          GEOBODY_B64: ${{ env.GEOBODY_B64 }}
         with:
           host: ${{ secrets.STAGING_HOST }}
           username: root
           key: ${{ secrets.STAGING_SSH_KEY }}
           command_timeout: 5m
-          envs: QUERY_B64,ECHO_B64,CFGKEYS_B64
+          envs: QUERY_B64,ECHO_B64,CFGKEYS_B64,GEOBODY_B64
           script: |
             set -e
             QUERY=$(printf '%s' "$QUERY_B64" | base64 -d)
             WANT=$(printf '%s' "$ECHO_B64" | base64 -d)
             CFGKEYS=$(printf '%s' "$CFGKEYS_B64" | base64 -d)
+            GEOBODY=$(printf '%s' "$GEOBODY_B64" | base64 -d)
             if ! docker network inspect retina-edge >/dev/null 2>&1; then
               echo "::error::retina-edge does not exist on $(hostname), so nginx cannot reach tower-finder-service and every proxied /api/towers would 502. Bring that stack up before routing a vhost to it."
               exit 1
@@ -452,6 +458,23 @@ jobs:
                 exit 1
               fi
             done
+
+            # /api/geocode, forwarded by the same include. An empty query is
+            # refused by the service's own request model with 422, before
+            # either geocoder upstream is asked; anything else means the
+            # instance behind this deploy does not carry the route yet, and
+            # every vhost would 404 the address lookup once it is pointed here.
+            GEO=$(docker run --rm --network retina-edge curlimages/curl:latest \
+              -s -m 45 -o /dev/null -w '%{http_code}' -X POST \
+              -H 'Content-Type: application/json' -d "$GEOBODY" \
+              "http://tower-finder-service:8000/api/geocode") || {
+              echo "::error::tower-finder-service did not answer /api/geocode on retina-edge from $(hostname)."
+              exit 1
+            }
+            if [ "$GEO" != "422" ]; then
+              echo "::error::staging's tower-finder-service answered /api/geocode with HTTP ${GEO}, not the 422 an empty query gets from the route. Either that instance predates the address lookup, or the request model changed. snippets/towers-proxy.conf forwards the route on every vhost, so pointing one at this instance would 404 the search form's address field."
+              exit 1
+            fi
             echo "staging's tower-finder-service honours the contract."
 
   # Does this push touch anything the droplets serve? A docs-only merge would
@@ -1141,6 +1164,15 @@ jobs:
             else
               echo "FAIL"; printf '    %s\n' "$REASON"; FAIL=$((FAIL+1))
             fi
+            # Strict, like config: the probe stops at the service's own input
+            # validation and never reaches a geocoder, so there is no third
+            # party here whose outage could roll production back.
+            printf "  %-40s " "${endpoint#https://}/api/geocode"
+            if REASON=$(assert_geocode_contract "${endpoint}/api/geocode"); then
+              echo "OK"; PASS=$((PASS+1))
+            else
+              echo "FAIL"; printf '    %s\n' "$REASON"; FAIL=$((FAIL+1))
+            fi
           done
 
           # Check aircraft data is flowing
diff --git a/ONBOARDING.md b/ONBOARDING.md
index 869e8227..ce81145e 100644
--- a/ONBOARDING.md
+++ b/ONBOARDING.md
@@ -25,7 +25,7 @@ One FastAPI backend serves several React front-ends, distinguished by subdomain:
 Illuminator search is deliberately absent from that table: **tower-finder-service**
 (separate repo and container) owns the API and the UI both, and serves
 `towers.retina.fm` from its own edge. Our vhosts only proxy `/api/towers`,
-`/api/elevation` and `/api/config` to it.
+`/api/elevation`, `/api/config` and `/api/geocode` to it.
 
 Receiver nodes connect over TCP and stream detection frames. The pipeline
 (tracker → geolocator) turns frames into aircraft positions, broadcast to the
diff --git a/README.md b/README.md
index de0fe2c1..6f2b50b6 100644
--- a/README.md
+++ b/README.md
@@ -13,14 +13,14 @@ and the admin dashboard.
 
 Finding a suitable broadcast illuminator near a receiver is **tower-finder-service**,
 a separate repo and container. It owns both halves: the API (`/api/towers`,
-`/api/elevation`, `/api/config`) and the UI, which it serves itself on
-`towers.retina.fm` through its own edge.
+`/api/elevation`, `/api/config`, `/api/geocode`) and the UI, which it serves itself
+on `towers.retina.fm` through its own edge.
 
 What remains here is the proxy seam. `api.retina.fm/towers` forwards to the
 service for callers that want a clean public API name, and the other vhosts
-still forward `/api/towers`, `/api/elevation` and `/api/config` so that a
-request arriving at one of them reaches the single implementation rather than a
-404 from this backend.
+still forward `/api/towers`, `/api/elevation`, `/api/config` and `/api/geocode`
+so that a request arriving at one of them reaches the single implementation
+rather than a 404 from this backend.
 
 ## Project Structure
 
@@ -79,7 +79,8 @@ cd backend && .venv/bin/uvicorn main:app --reload
 
 The API runs at `http://localhost:8000`. Interactive docs at `/docs`. The tower
 search is not part of this process: run tower-finder-service (its own repo and
-container) if you need `/api/towers`, `/api/elevation` or `/api/config` locally.
+container) if you need `/api/towers`, `/api/elevation`, `/api/config` or
+`/api/geocode` locally.
 The live map and the dashboard do not need it.
 
 #### Database migrations
@@ -138,10 +139,10 @@ the routes as `x-retry` and `x-terminal`, and the vocabulary is defined in the
 contract's own description. A breaking change raises `NODE_API_VERSION` in
 `backend/routes/nodes.py`.
 
-### `GET /api/towers`, `GET /api/elevation`, `GET|PUT /api/config`
+### `GET /api/towers`, `GET /api/elevation`, `GET|PUT /api/config`, `POST /api/geocode`
 
 Answered by **tower-finder-service**, not by this backend. nginx proxies all
-three to that service on every vhost that answers `/api/` (see
+four to that service on every vhost that answers `/api/` (see
 `deploy/nginx/snippets/towers-proxy.conf` and the `TOWER_FINDER` conditional in
 `deploy/nginx/nginx.conf.template`); this repo keeps the SPA that calls them and
 the routing, and no longer keeps a second implementation of the search, the
diff --git a/backend/tests/test_towers_vhost_coverage.py b/backend/tests/test_towers_vhost_coverage.py
index 51767803..f0d05949 100644
--- a/backend/tests/test_towers_vhost_coverage.py
+++ b/backend/tests/test_towers_vhost_coverage.py
@@ -38,11 +38,11 @@
 }
 
 # The paths towers-proxy.conf hands to the service. Every vhost that includes it
-# must forward all three. This used to guard against a split-brain (each route
+# must forward all four. This used to guard against a split-brain (each route
 # answered by whichever implementation the vhost happened to reach); now that the
 # monolith's copy is deleted, a route missing from the snippet is a 404 on that
 # vhost instead — louder, but still only visible in production.
-_PROXIED_PATHS = ("/api/towers", "/api/elevation", "/api/config")
+_PROXIED_PATHS = ("/api/towers", "/api/elevation", "/api/config", "/api/geocode")
 
 
 def _server_blocks(text: str) -> list[str]:
@@ -93,10 +93,10 @@ def test_the_smoke_test_defines_every_url_it_is_expected_to_probe():
 def test_the_shared_snippet_proxies_every_deduplicated_path():
     """One vhost include must carry the whole tower stack, not just the search.
 
-    /api/elevation and /api/config have no implementation left in this repo, so a
-    route dropped from this snippet is not served at all on that vhost: the
-    request falls through `location /` to an app that no longer has the handler
-    and answers 404.
+    /api/elevation and /api/config have no implementation left in this repo, and
+    /api/geocode never had one, so a route dropped from this snippet is not
+    served at all on that vhost: the request falls through `location /` to an
+    app without the handler and answers 404.
     """
     snippet = (_TEMPLATE.parent / "snippets" / "towers-proxy.conf").read_text()
     locations = set(re.findall(r"^location\s+(\S+)\s*\{", snippet, re.M))
diff --git a/deploy/nginx/snippets/towers-proxy.conf b/deploy/nginx/snippets/towers-proxy.conf
index da798ce4..58f23b77 100644
--- a/deploy/nginx/snippets/towers-proxy.conf
+++ b/deploy/nginx/snippets/towers-proxy.conf
@@ -12,7 +12,7 @@
 # role token, so a hardcoded production name survives in the staging and test
 # renders only, and reads as a parity failure. Name the ROLE, not the host.
 #
-# All three are LONGER prefixes than `location /api/`, so nginx matches these
+# All four are LONGER prefixes than `location /api/`, so nginx matches these
 # first on every vhost that also defines that one. None of them is an exact
 # (`location =`) match anywhere in the template, so nothing outranks them.
 #
@@ -41,3 +41,17 @@ location /api/elevation {
 location /api/config {
     # RETINA_INCLUDE snippets/tower-finder.conf
 }
+
+# Address lookup for the search form's address field (the service's api.ts
+# geocodeAddress). POST only, and the one route here that this repo's own
+# bundle does not call yet: the field shipped in the service's UI first. It
+# is forwarded all the same, because the vhosts that serve either bundle must
+# answer the same set of tower routes — a vhost missing this one 404s the
+# lookup from the app's `location /` fallback, which never had the handler.
+#
+# The smoke probes send an empty query. The service's own validation refuses
+# that with 422 before either geocoder upstream is asked, so the check is
+# deterministic and cannot be mistaken for the fallback's 404.
+location /api/geocode {
+    # RETINA_INCLUDE snippets/tower-finder.conf
+}
diff --git a/deploy/render-nginx-config.py b/deploy/render-nginx-config.py
index c7e317f5..96336a99 100755
--- a/deploy/render-nginx-config.py
+++ b/deploy/render-nginx-config.py
@@ -73,9 +73,9 @@
 # routes the tower stack to the service, and there is no longer a second
 # implementation to fall back to — the monolith's copy was deleted once the
 # proxy went live — so a missing variable must not quietly leave a vhost
-# answering 404 on /api/towers, /api/elevation and /api/config. The laptop turns
-# it off because it runs no service and no retina-edge network, and would
-# otherwise 502; with it off those three routes simply do not exist there.
+# answering 404 on /api/towers, /api/elevation, /api/config and /api/geocode.
+# The laptop turns it off because it runs no service and no retina-edge network,
+# and would otherwise 502; with it off those four routes simply do not exist there.
 FLAGS = {"TLS": ("TLS_ENABLED", True), "TOWER_FINDER": ("TOWER_FINDER_ENABLED", True)}
 
 
diff --git a/deploy/staging-smoke-test.sh b/deploy/staging-smoke-test.sh
index ad5bbb4f..6b6e38f0 100644
--- a/deploy/staging-smoke-test.sh
+++ b/deploy/staging-smoke-test.sh
@@ -372,7 +372,7 @@ for endpoint in "${BASE_URL}/api/towers" "${MAP_URL}/api/towers" \
 done
 # The other half of the seam: a sibling /api/ path on the same vhost is still
 # served by the app. /api/radar/nodes has no counterpart on the service, so a
-# 200 here can only have come from the monolith — the proxy must take the three
+# 200 here can only have come from the monolith — the proxy must take the four
 # tower routes and nothing else.
 check_status  "sibling /api/ path stays on the app" "${MAP_URL}/api/radar/nodes"             "200"
 
@@ -431,6 +431,16 @@ if [ "$PUT_CODE" = "401" ] || [ "$PUT_CODE" = "403" ]; then
 else
     echo "FAIL ($PUT_CODE — expected 401 or 403; an open config write is a takeover)"; FAIL=$((FAIL+1))
 fi
+# The fourth route the include forwards. Same vhost as the two above, for the
+# same reason; the probe itself is in tower-contract.sh and never reaches a
+# geocoder upstream, so unlike elevation there is no degraded state to tolerate.
+printf "  %-40s " "dash /api/geocode answers"
+if REASON=$(assert_geocode_contract "${DASH_URL}/api/geocode"); then
+    echo "OK"; PASS=$((PASS+1))
+else
+    echo "FAIL"; printf '    %s
+' "$REASON"; FAIL=$((FAIL+1))
+fi
 
 echo ""
 echo "── Detection archive (dash /data) ──"
diff --git a/deploy/tower-contract.sh b/deploy/tower-contract.sh
index 70368c33..06cbe007 100644
--- a/deploy/tower-contract.sh
+++ b/deploy/tower-contract.sh
@@ -108,13 +108,14 @@ assert_tower_contract() {
     return 0
 }
 
-# ── The other two deduplicated routes ────────────────────────────────────────
+# ── The other deduplicated routes ────────────────────────────────────────────
 # /api/towers was never the whole tower stack. Every vhost that includes
-# snippets/towers-proxy.conf forwards /api/elevation and /api/config as well, so
-# all three are part of what the service must honour before a vhost points at
-# it. They get a shape assertion rather than a parameter echo: neither takes a
-# ranking parameter, and what a caller can be broken by is the response losing a
-# key it reads.
+# snippets/towers-proxy.conf forwards /api/elevation, /api/config and
+# /api/geocode as well, so all four are part of what the service must honour
+# before a vhost points at it. Elevation and config get a shape assertion
+# rather than a parameter echo: neither takes a ranking parameter, and what a
+# caller can be broken by is the response losing a key it reads. Geocode has
+# its own probe further down.
 #
 # The keys below were the ones BOTH implementations returned while retina still
 # had its own. That copy is deleted, so they now pin the shape retina's callers
@@ -254,6 +255,38 @@ assert_config_contract() {
     _assert_json_keys "config" "$1" $TOWER_CONTRACT_CONFIG_KEYS
 }
 
+# assert_geocode_contract <endpoint-url>     e.g. https://host/api/geocode
+# The address lookup, forwarded by the same include. Probed with an EMPTY query
+# on purpose: the service's request model refuses it with 422 before either of
+# its geocoder upstreams (US Census, Nominatim) is asked, so this neither spends
+# a third party's quota nor depends on one being up — the two things that made
+# elevation's probe tolerant. It is also unambiguous: the app's `location /`
+# fallback answers a route it never had with 404, never 422.
+TOWER_CONTRACT_GEOCODE_BODY='{"query":""}'
+assert_geocode_contract() {
+    local url="$1" code attempt
+    # Two attempts, as the siblings: a blip must not read as a routing fault.
+    for attempt in 1 2; do
+        code=$(curl -s --connect-timeout 10 --max-time "$TOWER_CONTRACT_MAX_TIME" \
+            -o /dev/null -w '%{http_code}' -X POST -H 'Content-Type: application/json' \
+            -d "$TOWER_CONTRACT_GEOCODE_BODY" "$url" 2>/dev/null) || {
+            [ "$attempt" = 1 ] && { sleep 5; continue; }
+            echo "geocode: unreachable after 2 attempts: ${url}"
+            return 1
+        }
+        [ "$code" = "422" ] && return 0
+        [ "$attempt" = 1 ] && { sleep 5; continue; }
+        if [ "$code" = "404" ]; then
+            echo "geocode: got HTTP 404 from ${url}. No \`location /api/geocode\` on that vhost:"
+            echo "the request fell through to the app, which has no such route. See"
+            echo "deploy/nginx/snippets/towers-proxy.conf."
+        else
+            echo "geocode: got HTTP ${code} from ${url}, expected 422 for an empty query"
+        fi
+        return 1
+    done
+}
+
 # Run directly (not sourced) to gate a deploy on the contract. Takes the
 # /api/towers endpoint; the sibling routes are derived from it, so a caller
 # cannot check the search and forget the other two.
@@ -290,11 +323,11 @@ if [ "${BASH_SOURCE[0]}" = "$0" ]; then
     # unchanged means it was not a /api/towers URL (the api vhost publishes the
     # search as /towers), and the siblings cannot be derived from it.
     if [ "$BASE" = "$TARGET" ]; then
-        echo "Skipping the /api/elevation and /api/config checks: ${TARGET} is not a /api/towers URL, so the sibling routes cannot be derived. Point this at the service's own /api/towers to cover them."
+        echo "Skipping the /api/elevation, /api/config and /api/geocode checks: ${TARGET} is not a /api/towers URL, so the sibling routes cannot be derived. Point this at the service's own /api/towers to cover them."
         exit "$RC"
     fi
 
-    for check in elevation config; do
+    for check in elevation config geocode; do
         printf 'Asserting %s/api/%s honours the shape our callers read... ' "$BASE" "$check"
         # 2 is tolerated for elevation only. For elevation it is a third party's
         # rate limiter, which has no bearing on whether a vhost may be pointed
diff --git a/docker-compose.local.yml b/docker-compose.local.yml
index 0f931113..b0724ff0 100644
--- a/docker-compose.local.yml
+++ b/docker-compose.local.yml
@@ -57,7 +57,7 @@ services:
       # This flag controls the nginx proxy and nothing else. There is no local
       # fallback behind it any more: the monolith's own tower stack was deleted
       # once every deployed vhost was proxied to the service, so with the flag
-      # off, /api/towers, /api/elevation and /api/config are 404s and the tower
+      # off, /api/towers, /api/elevation, /api/config and /api/geocode are 404s and the tower
       # search SPA on towers.localhost cannot function. To work on the tower
       # search locally, run tower-finder-service (its own repo and container)
       # and point this stack at it — do not expect this one to answer.