diff --git a/.env.docker b/.env.docker
index 1970851b..b96d923c 100644
--- a/.env.docker
+++ b/.env.docker
@@ -37,4 +37,4 @@ GOOGLE_CLIENT_ID=
 GOOGLE_CLIENT_SECRET=
 
 # Frontend
-PUBLIC_DJANGO_API_URL=http://localhost:8000
+PUBLIC_DJANGO_API_URL=http://backend:8000
diff --git a/README.md b/README.md
index 580bdae1..9c467397 100644
--- a/README.md
+++ b/README.md
@@ -61,7 +61,7 @@ cd Django-CRM
 docker compose up --build
 ```
 
-Frontend at http://localhost:5173, API and Swagger UI at http://localhost:8000/swagger-ui/. See
+Frontend at http://localhost:5181, API and Swagger UI at http://localhost:8000/swagger-ui/. See
 the [Docker quick start guide](docs/getting-started/docker-quick-start.md) for the default admin
 login, loading demo data, and what each service does.
 
diff --git a/backend/.env.example b/backend/.env.example
index 94509a00..d5fa5482 100644
--- a/backend/.env.example
+++ b/backend/.env.example
@@ -11,7 +11,7 @@ DOMAIN_NAME="http://localhost:8000"
 # CSAT survey, and the internal "assigned to you" notifications. Outside dev
 # (ENV_TYPE other than "dev") a loopback value is refused at startup, because
 # left at this default it mails customers a link to their own machine.
-FRONTEND_URL="http://localhost:5173"
+FRONTEND_URL="http://localhost:5181"
 
 # AWS (only needed for production / S3 storage)
 AWS_BUCKET_NAME=""
@@ -44,8 +44,8 @@ DEFAULT_FROM_EMAIL="noreply@localhost"
 ADMIN_EMAIL="admin@localhost"
 
 ALLOWED_HOSTS=localhost,127.0.0.1
-CORS_ALLOWED_ORIGINS=http://localhost:5173,http://127.0.0.1:5173
-CSRF_TRUSTED_ORIGINS=http://localhost:5173
+CORS_ALLOWED_ORIGINS=http://localhost:5181,http://127.0.0.1:5181
+CSRF_TRUSTED_ORIGINS=http://localhost:5181
 
 # Set to True only when TLS is terminated by a proxy in front of Django and that
 # proxy is the only way in. It makes Django trust X-Forwarded-Proto, which is
diff --git a/backend/README.md b/backend/README.md
index 43a9ec4f..421c7ffe 100644
--- a/backend/README.md
+++ b/backend/README.md
@@ -156,7 +156,7 @@ CELERY_RESULT_BACKEND=redis://localhost:6379/0
 # The web app, NOT this API. Every link the backend emails is built from it:
 # the magic-link sign-in URL, the customer invoice and estimate portals, the
 # CSAT survey. Point it at the API host and every one of those links 404s.
-FRONTEND_URL=http://localhost:5173
+FRONTEND_URL=http://localhost:5181
 
 # Google sign-in. Without these the OAuth login flow cannot complete, which is
 # the only interactive way into the app.
@@ -164,7 +164,7 @@ GOOGLE_CLIENT_ID=your-google-client-id
 GOOGLE_CLIENT_SECRET=your-google-client-secret
 
 # Where the browser calls this API from. The SvelteKit dev server by default.
-CORS_ALLOWED_ORIGINS=http://localhost:5173
+CORS_ALLOWED_ORIGINS=http://localhost:5181
 
 # This API's own public origin
 DOMAIN_NAME=http://localhost:8000
diff --git a/backend/common/tests/test_frontend_url_guard.py b/backend/common/tests/test_frontend_url_guard.py
index a5eb6efb..7ab19f7a 100644
--- a/backend/common/tests/test_frontend_url_guard.py
+++ b/backend/common/tests/test_frontend_url_guard.py
@@ -3,7 +3,7 @@
 ``common.links.frontend_url`` builds all of them from it: the customer's invoice
 and estimate portal links, the CSAT survey, the internal "assigned to you"
 notifications, and, directly in ``common/tasks.py``, the magic-link sign-in URL.
-It defaults to ``http://localhost:5173`` so a checkout works with no ``.env``,
+It defaults to ``http://localhost:5181`` so a checkout works with no ``.env``,
 which means a deployment that never sets it mails customers a link to a port on
 their own machine and mails a sign-in token to one. Nothing on the server
 reports it: the email sends, the link is simply dead on arrival.
@@ -56,31 +56,31 @@ def _import_settings(frontend_url, env_type):
 class TestALoopbackFrontendUrlIsRefusedOutsideDev:
     def test_the_dev_default_fails_the_import(self):
         """The exact value an operator gets by not setting the variable."""
-        result = _import_settings("http://localhost:5173", "production")
+        result = _import_settings("http://localhost:5181", "production")
 
         assert result.returncode != 0
         assert "FRONTEND_URL" in result.stderr
 
     def test_the_error_says_what_to_set_it_to(self):
         """A refusal that does not say what to do next is a support ticket."""
-        result = _import_settings("http://localhost:5173", "production")
+        result = _import_settings("http://localhost:5181", "production")
 
         assert "https://app.example.com" in result.stderr
 
     def test_the_error_says_the_link_reaches_customers(self):
         """The operator needs to know this is outward-facing, not internal."""
-        result = _import_settings("http://localhost:5173", "production")
+        result = _import_settings("http://localhost:5181", "production")
 
         assert "customers" in result.stderr
 
     def test_the_loopback_address_fails_too(self):
-        result = _import_settings("http://127.0.0.1:5173", "production")
+        result = _import_settings("http://127.0.0.1:5181", "production")
 
         assert result.returncode != 0
 
     def test_the_wildcard_bind_address_fails(self):
         """`0.0.0.0` is what a Docker compose file tends to carry."""
-        result = _import_settings("http://0.0.0.0:5173", "production")
+        result = _import_settings("http://0.0.0.0:5181", "production")
 
         assert result.returncode != 0
 
@@ -141,7 +141,7 @@ class TestANonAbsoluteFrontendUrlIsRefusedOutsideDev:
 class TestDevIsLeftAlone:
     def test_the_dev_default_imports_cleanly_in_dev(self):
         """In dev the loopback URL is the correct answer, not a warning."""
-        result = _import_settings("http://localhost:5173", "dev")
+        result = _import_settings("http://localhost:5181", "dev")
 
         assert result.returncode == 0, result.stderr
         assert "FRONTEND_URL" not in result.stderr
diff --git a/backend/common/tests/test_tag_slugs.py b/backend/common/tests/test_tag_slugs.py
index 99ad652a..5ab091db 100644
--- a/backend/common/tests/test_tag_slugs.py
+++ b/backend/common/tests/test_tag_slugs.py
@@ -9,6 +9,7 @@ rule, and `Tags.name_error` the one owner of what a storable name is.
 """
 
 import importlib
+import uuid
 from types import SimpleNamespace
 
 import pytest
@@ -207,8 +208,10 @@ class TestRecomputeMigration:
         module.recompute_tag_slugs(global_apps, SimpleNamespace(connection=connection))
 
     def _with_slug(self, org, name, slug):
-        # save() recomputes the slug, so store the old one with update().
-        tag = Tags.objects.create(name=f"placeholder {name}", org=org)
+        # save() recomputes the slug, so store the old one with update(). The
+        # placeholder must fit `name`'s 50 characters: Postgres enforces the
+        # width and SQLite does not, so a longer one only fails on Postgres.
+        tag = Tags.objects.create(name=f"placeholder {uuid.uuid4().hex}", org=org)
         Tags.objects.filter(pk=tag.pk).update(name=name, slug=slug)
         return tag
 
diff --git a/backend/crm/settings.py b/backend/crm/settings.py
index 2f69608b..7f692654 100644
--- a/backend/crm/settings.py
+++ b/backend/crm/settings.py
@@ -454,7 +454,7 @@ CORS_ORIGIN_ALLOW_ALL = os.environ.get("CORS_ALLOW_ALL", "False").lower() == "tr
 CORS_ALLOWED_ORIGINS = [
     origin.strip()
     for origin in os.environ.get(
-        "CORS_ALLOWED_ORIGINS", "http://localhost:5173,http://127.0.0.1:5173"
+        "CORS_ALLOWED_ORIGINS", "http://localhost:5181,http://127.0.0.1:5181"
     ).split(",")
     if origin.strip()
 ]
@@ -523,7 +523,7 @@ DOMAIN_NAME = os.environ.get("DOMAIN_NAME", "http://localhost:8000")
 ORG_API_KEY_AUTH_ENABLED = os.environ.get(
     "DJANGO_ORG_API_KEY_AUTH", "true"
 ).strip().lower() not in ("false", "0", "no", "off")
-FRONTEND_URL = os.environ.get("FRONTEND_URL", "http://localhost:5173")
+FRONTEND_URL = os.environ.get("FRONTEND_URL", "http://localhost:5181")
 
 # Every link this system puts in an email is built from this one value, via
 # `common.links.frontend_url`: the magic-link sign-in URL, the customer's
diff --git a/docker-compose.yml b/docker-compose.yml
index 3203c960..746bbadd 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -101,7 +101,7 @@ services:
       - ./frontend:/app
       - frontend_node_modules:/app/node_modules
     ports:
-      - "5173:5173"
+      - "5181:5181"
 
 volumes:
   postgres_data:
diff --git a/docs/api/conventions.md b/docs/api/conventions.md
index aec8d877..07907121 100644
--- a/docs/api/conventions.md
+++ b/docs/api/conventions.md
@@ -16,8 +16,8 @@ of this section's page references point at, at the same, empty prefix. Individua
 under their own segment from there, for example `path("leads/", include("leads.urls", ...))`, so a
 lead endpoint is `/api/leads/…`.
 
-Locally this is `http://localhost:8000/api/` (the default in the Docker quick start's
-`.env.docker`, and what `PUBLIC_DJANGO_API_URL` points the frontend at. See
+Locally this is `http://localhost:8000/api/` (the port the Docker quick start publishes. Inside
+the compose network the frontend reaches the same API as `http://backend:8000`. See
 [Docker quick start](../getting-started/docker-quick-start.md)). In a self-hosted deployment it is
 whatever host you put `DOMAIN_NAME` / `ALLOWED_HOSTS` on, still under `/api/`.
 
diff --git a/docs/contributing/development-setup.md b/docs/contributing/development-setup.md
index 2637f9cb..0c7d288e 100644
--- a/docs/contributing/development-setup.md
+++ b/docs/contributing/development-setup.md
@@ -66,11 +66,11 @@ pnpm install
 pnpm run dev
 ```
 
-`pnpm run dev` starts the Vite dev server on `http://localhost:5173`. `frontend/vite.config.js`
+`pnpm run dev` starts the Vite dev server on `http://localhost:5181`. `frontend/vite.config.js`
 configures no dev-server proxy, there is no `server.proxy` entry in it, so the browser calls the
 Django API directly, cross-origin: `frontend/src/lib/api.js` builds its base URL from
 `PUBLIC_DJANGO_API_URL`, defaulting to `http://localhost:8000/api` when that variable is unset. That
-means your backend's `CORS_ALLOWED_ORIGINS` has to include `http://localhost:5173` (it does by
+means your backend's `CORS_ALLOWED_ORIGINS` has to include `http://localhost:5181` (it does by
 default in `backend/.env.example`: see [Manual setup](../getting-started/manual-setup.md)) or every
 request from the dev server fails as a CORS error, not a 404 or connection-refused, which is easy to
 misdiagnose as a backend problem.
diff --git a/docs/getting-started/docker-quick-start.md b/docs/getting-started/docker-quick-start.md
index e5d58863..38a87509 100644
--- a/docs/getting-started/docker-quick-start.md
+++ b/docs/getting-started/docker-quick-start.md
@@ -36,7 +36,7 @@ The variables `.env.docker` actually defines are:
 | `DEFAULT_FROM_EMAIL`, `ADMIN_EMAIL`, `ADMIN_PASSWORD` | Console email backend (dev), and the credentials used to bootstrap a Django admin superuser. See [What you got](#what-you-got). |
 | `CORS_ALLOW_ALL` | `True` for local development. |
 | `GOOGLE_CLIENT_ID`, `GOOGLE_CLIENT_SECRET` | Blank by default; Google sign-in is disabled until both are set. The redirect URI is not a setting: the frontend sends it in the request body on each call. |
-| `PUBLIC_DJANGO_API_URL` | The API base URL the frontend container is built against, `http://localhost:8000`. |
+| `PUBLIC_DJANGO_API_URL` | The API origin the frontend's server-side code calls, `http://backend:8000`. It uses the compose service name because `localhost` inside the frontend container is the container itself. Your browser still reaches the API at `http://localhost:8000`. |
 
 ## Start the stack
 
@@ -53,7 +53,7 @@ This builds and starts six services, defined in `docker-compose.yml`:
 | `backend` | built from the repo root `Dockerfile` | `8000` |
 | `celery-worker` | same image as `backend`, runs `celery -A crm worker --loglevel=info` |. |
 | `celery-beat` | same image as `backend`, runs `celery -A crm beat --loglevel=info` |, |
-| `frontend` | built from `frontend/Dockerfile` | `5173` |
+| `frontend` | built from `frontend/Dockerfile` | `5181` |
 
 `backend`, `celery-worker` and `celery-beat` all wait for `db` and `redis` to report healthy
 before starting. The `backend` container's entrypoint (`docker/backend/entrypoint.sh`) waits for
@@ -106,7 +106,7 @@ docker compose exec backend python manage.py devlogin you@example.com --org Micr
 
 This prints an access token, a refresh token, and the `MicroPyramid` org's UUID, already bound
 into the token. See [First sign-in](first-sign-in.md) for how to use them from the frontend at
-`http://localhost:5173`.
+`http://localhost:5181`.
 
 ## What you got
 
@@ -117,7 +117,7 @@ After `docker compose up --build` and one `seed_data` run, you have:
   server. This compose file is for development).
 - A Celery worker and a Celery beat scheduler, both connected to the `redis` service, running the
   periodic and background tasks registered in `backend/crm/celery.py`.
-- A SvelteKit frontend on `http://localhost:5173`, built against `PUBLIC_DJANGO_API_URL=http://localhost:8000`.
+- A SvelteKit frontend on `http://localhost:5181`, which reaches the API over the compose network at `PUBLIC_DJANGO_API_URL=http://backend:8000`.
 - A Django admin superuser, created automatically by `create_default_admin` on first boot, using
   `ADMIN_EMAIL` / `ADMIN_PASSWORD` from `.env.docker` (`admin@localhost` / `admin` unless you
   override them). This account can sign in to Django's own `/admin/` site; it does not have a CRM
diff --git a/docs/getting-started/first-sign-in.md b/docs/getting-started/first-sign-in.md
index 12e67ed5..b635bab4 100644
--- a/docs/getting-started/first-sign-in.md
+++ b/docs/getting-started/first-sign-in.md
@@ -64,7 +64,7 @@ instead (`event.cookies.get('jwt_access')`, `('jwt_refresh')` and `('org')`), an
 server-side reads `localStorage` at all. Without those cookies set, `hooks.server.js` treats the
 request as signed out and redirects to `/login`, no matter what `localStorage` holds.
 
-To get past the guard, open the devtools console on `http://localhost:5173`, run the printed
+To get past the guard, open the devtools console on `http://localhost:5181`, run the printed
 `localStorage.setItem(...)` snippet, and set the matching cookies yourself:
 
 ```js
diff --git a/docs/getting-started/manual-setup.md b/docs/getting-started/manual-setup.md
index b1034b80..cebc6005 100644
--- a/docs/getting-started/manual-setup.md
+++ b/docs/getting-started/manual-setup.md
@@ -144,7 +144,7 @@ you're following the ports in this guide). Then start the dev server:
 pnpm run dev
 ```
 
-This serves the SvelteKit app on `http://localhost:5173` (`vite dev` under the hood, per the
+This serves the SvelteKit app on `http://localhost:5181` (`vite dev` under the hood, per the
 `dev` script in `frontend/package.json`).
 
 ## Running all three
diff --git a/docs/reference/environment-variables.md b/docs/reference/environment-variables.md
index ff7e8fe9..87632438 100644
--- a/docs/reference/environment-variables.md
+++ b/docs/reference/environment-variables.md
@@ -112,7 +112,7 @@ Pooling uses psycopg 3's `psycopg_pool` through Django's PostgreSQL backend. It
 | Variable | Default | Required | Purpose |
 | --- | --- | --- | --- |
 | `CORS_ALLOW_ALL` | `False` | No | Sets Django's `CORS_ORIGIN_ALLOW_ALL`. Note the name doesn't match the Django setting it controls. `"true"` (case-insensitive) allows every origin; anything else leaves it off. |
-| `CORS_ALLOWED_ORIGINS` | `http://localhost:5173,http://127.0.0.1:5173` | Yes, once the frontend is served from a real domain | Comma-separated list of allowed CORS origins; each entry is stripped of surrounding whitespace and empty entries are dropped. |
+| `CORS_ALLOWED_ORIGINS` | `http://localhost:5181,http://127.0.0.1:5181` | Yes, once the frontend is served from a real domain | Comma-separated list of allowed CORS origins; each entry is stripped of surrounding whitespace and empty entries are dropped. |
 | `CSRF_TRUSTED_ORIGINS` | *(empty, no trusted origins)* | Yes, before anyone but you can reach the instance | Comma-separated list, same stripping rule as `CORS_ALLOWED_ORIGINS`. Each entry needs a scheme, e.g. `https://crm.example.com`. A bare hostname is silently useless to Django's CSRF check. |
 
 ### URLs
@@ -120,7 +120,7 @@ Pooling uses psycopg 3's `psycopg_pool` through Django's PostgreSQL backend. It
 | Variable | Default | Required | Purpose |
 | --- | --- | --- | --- |
 | `DOMAIN_NAME` | `http://localhost:8000` | No. Nothing reads it any more | Base URL of the **backend**. It no longer reaches a single emitted link. The four remaining reads (`invoices/tasks.py:305,482` and `invoices/api_views.py:276,436`) pass it as the `domain=` kwarg of Celery tasks whose signatures keep that parameter only so a task queued before the change still unpacks after deploy, and whose docstrings say it is ignored. Every link now comes from `FRONTEND_URL` via `common/links.py`. It used to build the internal "assigned to you" notifications as well as the customer-facing invoice, estimate and CSAT links, and every one of those was broken: the builders wrote `f"{protocol}://{domain}/..."` around a value that already carried a scheme, so the emitted link had two, and the paths are frontend routes that do not exist on the backend host. Setting this variable changes nothing; it is kept so an existing `.env` does not have to be edited. |
-| `FRONTEND_URL` | `http://localhost:5173` | **Yes**, once self-hosted under a real domain | Base URL of the SvelteKit frontend, and the single source for every link that leaves the system in an email: the welcome email and magic-link sign-in URL (`common/tasks.py`), the emailed invoice and estimate portal links, the CSAT survey link, and the "assigned to you" invoice link (all via `common.links.frontend_url`). The customer-facing ones go to people outside the organization, so leaving the `localhost` default in a real deployment emails dead links to customers. **That is now refused rather than emailed:** when `ENV_TYPE` is anything other than `dev`, `crm/settings.py` raises at import if this points at a loopback host (`localhost`, `127.0.0.1`, `0.0.0.0`, `::1`) or is not an absolute `http`/`https` URL, so the deploy fails to start instead of failing silently on somebody else's inbox. Plain HTTP against a real host is allowed, for a deployment behind its own TLS terminator. A trailing slash is stripped, so `https://app.example.com` and `https://app.example.com/` behave the same. |
+| `FRONTEND_URL` | `http://localhost:5181` | **Yes**, once self-hosted under a real domain | Base URL of the SvelteKit frontend, and the single source for every link that leaves the system in an email: the welcome email and magic-link sign-in URL (`common/tasks.py`), the emailed invoice and estimate portal links, the CSAT survey link, and the "assigned to you" invoice link (all via `common.links.frontend_url`). The customer-facing ones go to people outside the organization, so leaving the `localhost` default in a real deployment emails dead links to customers. **That is now refused rather than emailed:** when `ENV_TYPE` is anything other than `dev`, `crm/settings.py` raises at import if this points at a loopback host (`localhost`, `127.0.0.1`, `0.0.0.0`, `::1`) or is not an absolute `http`/`https` URL, so the deploy fails to start instead of failing silently on somebody else's inbox. Plain HTTP against a real host is allowed, for a deployment behind its own TLS terminator. A trailing slash is stripped, so `https://app.example.com` and `https://app.example.com/` behave the same. |
 
 ### Google OAuth
 
diff --git a/docs/self-hosting/docker.md b/docs/self-hosting/docker.md
index c9a7813b..ee845365 100644
--- a/docs/self-hosting/docker.md
+++ b/docs/self-hosting/docker.md
@@ -24,7 +24,7 @@ requirements in [Production deployment](production-deploy.md).
 | `backend` | built from the repo-root `Dockerfile` | `8000` | The Django API, served via `manage.py runserver` in this compose file (see the warning above). |
 | `celery-worker` | same image as `backend` |, (no published port) | Runs `celery -A crm worker --loglevel=info`; executes background tasks such as outbound email and RLS-context-aware jobs in `backend/common/tasks.py`. |
 | `celery-beat` | same image as `backend` |, (no published port) | Runs `celery -A crm beat --loglevel=info`; fires the periodic tasks registered in `backend/crm/celery.py` (recurring invoices, overdue/expiry checks, SLA scanning, cleanup jobs) on their schedules. |
-| `frontend` | built from `frontend/Dockerfile` | `5173` | The SvelteKit app, served via `pnpm dev --host 0.0.0.0`, also a dev server, not a production build. |
+| `frontend` | built from `frontend/Dockerfile` | `5181` | The SvelteKit app, served via `pnpm dev --host 0.0.0.0`, also a dev server, not a production build. |
 
 `backend`, `celery-worker` and `celery-beat` each declare `depends_on: db (service_healthy), redis
 (service_healthy)`, using the `pg_isready` and `redis-cli ping` healthchecks defined on those two
@@ -47,7 +47,8 @@ superuser role. See [PostgreSQL and RLS](postgresql-and-rls.md) for why the app
 as this role), `CELERY_BROKER_URL`/`CELERY_RESULT_BACKEND` (both pointing at `redis`),
 `DEFAULT_FROM_EMAIL`/`ADMIN_EMAIL`/`ADMIN_PASSWORD`, `CORS_ALLOW_ALL=True`,
 `GOOGLE_CLIENT_ID`/`GOOGLE_CLIENT_SECRET` (blank. Google sign-in stays disabled until both
-are set), and `PUBLIC_DJANGO_API_URL=http://localhost:8000` for the frontend build.
+are set), and `PUBLIC_DJANGO_API_URL=http://backend:8000`, the compose service name the
+frontend's server-side code uses to reach the API.
 
 ## Running it
 
diff --git a/docs/self-hosting/google-oauth.md b/docs/self-hosting/google-oauth.md
index d326d526..90ddf22e 100644
--- a/docs/self-hosting/google-oauth.md
+++ b/docs/self-hosting/google-oauth.md
@@ -11,7 +11,7 @@ Create an OAuth 2.0 Client ID of type "Web application" in the Google Cloud Cons
 URI it needs authorized is built by the frontend's login page
 (`frontend/src/routes/(no-layout)/login/+page.server.js`) as `${GOOGLE_LOGIN_DOMAIN}/login`;
 `GOOGLE_LOGIN_DOMAIN` is a **frontend** environment variable (`frontend/.env.example` defaults it to
-`http://localhost:5173`), so the value to register with Google is `http://localhost:5173/login` for
+`http://localhost:5181`), so the value to register with Google is `http://localhost:5181/login` for
 local development, or `https://<your-frontend-host>/login` in production. There is no separate
 redirect registration needed for the mobile flow. It doesn't use a redirect at all (see
 [Mobile ID tokens](#mobile-id-tokens) below).
diff --git a/frontend/.env.example b/frontend/.env.example
index 6ab492a6..49d0a5e9 100644
--- a/frontend/.env.example
+++ b/frontend/.env.example
@@ -1,6 +1,6 @@
 # Google OAuth (client_id only - secret is on backend)
 GOOGLE_CLIENT_ID="your-google-client-id-here"
-GOOGLE_LOGIN_DOMAIN="http://localhost:5173"
+GOOGLE_LOGIN_DOMAIN="http://localhost:5181"
 
 # Django API URL (PUBLIC_ prefix makes it available in both server and browser)
 PUBLIC_DJANGO_API_URL=http://localhost:8000
diff --git a/frontend/Dockerfile b/frontend/Dockerfile
index 0d81eb35..ec5a2b9d 100644
--- a/frontend/Dockerfile
+++ b/frontend/Dockerfile
@@ -40,7 +40,7 @@ RUN pnpm install --frozen-lockfile
 # The compose target. Source and node_modules arrive as mounts, so this stage
 # deliberately copies no source of its own.
 FROM deps AS dev
-EXPOSE 5173
+EXPOSE 5181
 CMD ["pnpm", "dev", "--host", "0.0.0.0"]
 
 
diff --git a/frontend/README.md b/frontend/README.md
index a7abee49..fbeda67a 100644
--- a/frontend/README.md
+++ b/frontend/README.md
@@ -108,7 +108,7 @@ JWT_SECRET="<your-generated-secret>"
 # Google OAuth (Optional)
 GOOGLE_CLIENT_ID=""
 GOOGLE_CLIENT_SECRET=""
-GOOGLE_LOGIN_DOMAIN="http://localhost:5173"
+GOOGLE_LOGIN_DOMAIN="http://localhost:5181"
 ```
 
 5. **Set up the database:**