diff --git a/.github/workflows/migrations.yml b/.github/workflows/migrations.yml
new file mode 100644
index 0000000000..e80985f2ed
--- /dev/null
+++ b/.github/workflows/migrations.yml
@@ -0,0 +1,71 @@
+name: Migrations
+
+# Replaces the "Supabase Preview" check, which never worked: it fired
+# only on migration changes and then either 404'd in four seconds
+# ("Postgres config not found") or hung forever waiting on a branch
+# action, because two stale dashboard integrations were pointed at this
+# repo and neither could provision. It never applied a migration, so
+# every `supabase/migrations/*.sql` file in this repo has shipped
+# unexecuted by CI.
+#
+# This job does the thing that check only claimed to: boot a clean
+# Postgres and replay every migration, in order, from nothing. It needs
+# no secrets and no Supabase account — the CLI runs the database in a
+# container on the runner.
+
+on:
+  pull_request:
+    # `supabase/**` rather than `supabase/migrations/**` so a change to
+    # config.toml re-runs the check too, and this workflow is listed so
+    # that edits to the check are validated by the check.
+    #
+    # NOTE: if this is ever made a REQUIRED status check, drop these
+    # filters. GitHub leaves a required check that never ran stuck as
+    # "expected", which blocks every PR that doesn't touch SQL.
+    paths:
+      - 'supabase/**'
+      - '.github/workflows/migrations.yml'
+  push:
+    branches: [main]
+    paths:
+      - 'supabase/**'
+      - '.github/workflows/migrations.yml'
+
+concurrency:
+  group: migrations-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  apply:
+    name: Apply to a clean database
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v7
+
+      - name: Install the Supabase CLI
+        uses: supabase/setup-cli@v1
+        with:
+          # Pinned rather than `latest`: this check is infrastructure,
+          # and a CLI release changing behaviour should be a deliberate
+          # bump in a PR, not a Tuesday where main goes red.
+          version: 2.113.0
+
+      - name: Start Postgres
+        run: supabase db start
+
+      # `db start` already applies the migrations on a cold volume, but
+      # only on a cold volume — it is a no-op against a database that
+      # already exists. `db reset` drops and rebuilds unconditionally,
+      # so this step, not the one above, is the guarantee that every
+      # migration ran in filename order against nothing. It fails on the
+      # first statement Postgres rejects. --no-seed because there is no
+      # seed script and this is about schema, not data.
+      - name: Replay every migration from scratch
+        run: supabase db reset --local --no-seed
+
+      # A migration can apply "successfully" and still do nothing —
+      # every DDL statement here is IF NOT EXISTS-guarded, which turns a
+      # typo'd object name into a silent no-op. Assert the outcome, not
+      # just the absence of an error.
+      - name: Verify the resulting schema
+        run: supabase db query --local --file supabase/ci/verify-schema.sql
diff --git a/supabase/ci/verify-schema.sql b/supabase/ci/verify-schema.sql
new file mode 100644
index 0000000000..d3c5b23928
--- /dev/null
+++ b/supabase/ci/verify-schema.sql
@@ -0,0 +1,62 @@
+-- Post-migration assertions for the CI job in
+-- `.github/workflows/migrations.yml`.
+--
+-- `supabase db reset` already fails on any statement Postgres rejects,
+-- so this is not about syntax. It's about the quieter failure: a
+-- migration that applies cleanly and does nothing. Every DDL statement
+-- in this repo is guarded with IF NOT EXISTS / ON CONFLICT so the files
+-- can be re-run safely, and that same guard turns a typo'd object name
+-- into a silent no-op with a green checkmark.
+--
+-- Keep this thin. It is a smoke test for "did the migrations actually
+-- build the schema", not a spec of it — asserting every column here
+-- would just be the migrations restated in a second place, drifting.
+DO $$
+BEGIN
+  -- The core tables, from 001.
+  IF to_regclass('public.messages') IS NULL THEN
+    RAISE EXCEPTION 'public.messages is missing — migrations did not apply';
+  END IF;
+  IF to_regclass('public.whatsapp_config') IS NULL THEN
+    RAISE EXCEPTION 'public.whatsapp_config is missing — migrations did not apply';
+  END IF;
+
+  -- Supabase provides the storage schema; migrations 016/020/023 write
+  -- to it. If it is absent the bucket migrations silently accomplish
+  -- nothing, which is precisely the case a plain "no errors" run hides.
+  IF to_regclass('storage.buckets') IS NULL THEN
+    RAISE EXCEPTION
+      'storage.buckets is missing — the storage schema was not available when the bucket migrations ran';
+  END IF;
+
+  -- Buckets are UPSERTed, so their absence means the INSERT never ran.
+  IF NOT EXISTS (SELECT 1 FROM storage.buckets WHERE id = 'chat-media') THEN
+    RAISE EXCEPTION 'the chat-media bucket row was not created (migration 023)';
+  END IF;
+  IF NOT EXISTS (SELECT 1 FROM storage.buckets WHERE id = 'flow-media') THEN
+    RAISE EXCEPTION 'the flow-media bucket row was not created (migration 016)';
+  END IF;
+
+  -- Account scoping (017) is load-bearing for every RLS policy.
+  IF to_regclass('public.accounts') IS NULL THEN
+    RAISE EXCEPTION 'public.accounts is missing — migration 017 did not apply';
+  END IF;
+
+  RAISE NOTICE 'schema verification passed';
+END
+$$;
+
+-- Two things this file has already been burned by, both verified in CI
+-- rather than assumed:
+--
+-- 1. It must contain EXACTLY ONE statement. `supabase db query --file`
+--    sends the whole file as a prepared statement, and a second
+--    top-level statement fails with the distinctly unhelpful "cannot
+--    insert multiple commands into a prepared statement" (commit
+--    f91a6c8). Add assertions INSIDE the DO block above; do not append
+--    a second one.
+--
+-- 2. A RAISE in here really does fail the job. A deliberately false
+--    assertion (commit 42c7db0, run 31579334056) surfaced as
+--    `failed to execute query: error: ...` and exited 1. This is not a
+--    decorative green tick.
diff --git a/supabase/config.toml b/supabase/config.toml
new file mode 100644
index 0000000000..9f66337d37
--- /dev/null
+++ b/supabase/config.toml
@@ -0,0 +1,24 @@
+# Supabase CLI configuration.
+#
+# This file exists for ONE reason: the CI job in
+# `.github/workflows/migrations.yml` needs a project directory the CLI
+# recognises before it can boot a throwaway Postgres and replay
+# `supabase/migrations/` against it.
+#
+# It is NOT a mirror of the hosted project's settings. Auth providers,
+# storage limits, SMTP, rate limits and the rest are configured in the
+# Supabase dashboard and are deliberately left out here rather than
+# duplicated into a second source of truth that would quietly drift.
+# Run `supabase init` if you ever want the CLI's full annotated
+# reference version of this file.
+project_id = "wacrm"
+
+[db]
+port = 54322
+shadow_port = 54320
+# Keep this aligned with the hosted project's Postgres version
+# (Dashboard → Settings → Infrastructure). A mismatch means CI can
+# green-light SQL the production database would reject, which is the
+# one failure mode this whole check exists to prevent. 17 is the CLI's
+# current default, not a reading of the live project.
+major_version = 17