Supabase

# Supabase

## Core Principles

**1. Supabase changes frequently — verify against changelog and current docs before implementing.** Do not rely on training data for Supabase features. Function signatures, config.toml settings, and API conventions change between versions.

First, fetch `https://supabase.com/changelog.md` (a lightweight summary index — not a heavy pull), scan for `breaking-change` tags relevant to your task, and follow the linked page for any that apply. Then look up the relevant topic using the documentation access methods below.

**2. Verify your work.** After implementing any fix, run a test query to confirm the change works. A fix without verification is incomplete.

**3. Recover from errors, don't loop.** If an approach fails after 2-3 attempts, stop and reconsider. Try a different method, check documentation, inspect the error more carefully, and review relevant logs when available. Supabase issues are not always solved by retrying the same command, and the answer is not always in the logs, but logs are often worth checking before proceeding.

**4. Exposing tables to the Data API:** Depending on the user's [Data API settings](https://supabase.com/dashboard/project/<ref>/integrations/data_api/settings), newly created tables may not be automatically exposed via the Data (REST) API. If this is the case, `anon` and `authenticated` roles will need to be explicitly granted access.

> Note that this is separate from RLS, which controls which _rows_ are visible once a table is accessible, not whether the table is accessible at all.

When a user reports a SQL-created table is unexpectedly inaccessible, check their Data API settings and whether the roles have been granted access via explicit `GRANT` SQL. When granting public (`anon`/`authenticated`) access, always enable RLS too. See [Exposing a Table to the Data API](https://supabase.com/docs/guides/api/securing-your-api.md) for the full setup workflow.

**5. RLS in exposed schemas.** Enable RLS on every table in any exposed schema, which includes `public` by default. This is critical in Supabase because tables in exposed schemas can be reachable through the Data API when the `anon`/`authenticated` roles have access (see [Exposing a Table to the Data API](https://supabase.com/docs/guides/api/securing-your-api.md)). For private schemas, prefer RLS as defense in depth. After enabling RLS, create policies that match the actual access model rather than defaulting every table to the same `auth.uid()` pattern.

**6. Security checklist.** When working on any Supabase task that touches auth, RLS, views, storage, or user data, run through this checklist. These are Supabase-specific security traps that silently create vulnerabilities:

- **Auth and session security** - **Never use `user_metadata` claims in JWT-based authorization decisions.** In Supabase, `raw_user_meta_data` is user-editable and can appear in `auth.jwt()`, so it is unsafe for RLS policies or any other authorization logic. Store authorization data in `raw_app_meta_data` / `app_metadata` instead. - **Deleting a user does not invalidate existing access tokens.** Sign out or revoke sessions first, keep JWT expiry short for sensitive apps, and for strict guarantees validate `session_id` against `auth.sessions` on sensitive operations. - **If you use `app_metadata` or `auth.jwt()` for authorization, remember JWT claims are not always fresh until the user's token is refreshed.**

- **API key and client exposure** - **Never expose the `service_role` or secret key in public clients.** Prefer publishable keys for frontend code. Legacy `anon` keys are only for compatibility. In Next.js, any `NEXT_PUBLIC_` env var is sent to the browser. - **Use scoped personal access tokens for the Management API, CLI, and MCP server.** A classic personal access token carries the user's full account access, on every organization and project. For scripts, CI, and agents, have the user create a scoped token limited to the organizations, projects, and permissions the task needs. The [personal access tokens guide](https://supabase.com/docs/guides/platform/personal-access-tokens.md) lists the permission each Management API endpoint and MCP tool requires. Look permissions up there rather than guessing.

- **RLS, views, and privileged database code** - **Views bypass RLS by default.** In Postgres 15 and above, use `CREATE VIEW ... WITH (security_invoker = true)`. In older versions of Postgres, protect your views by revoking access from the `anon` and `authenticated` roles, or by putting them in an unexposed schema. - **UPDATE requires a SELECT policy.** In Postgres RLS, an UPDATE needs to first SELECT the row. Without a SELECT policy, updates silently return 0 rows — no error, just no change. - **`auth.role()` is deprecated — use the `TO` clause instead.** Supabase has deprecated `auth.role()` in favour of specifying the target role directly on the policy with `TO authenticated` or `TO anon`. Beyond depre