# Claim helpers (/using/app-users/claim-helpers)



In the `chelabase` schema of every database the data API serves, Chelabase installs three functions that read the claims of the signed-in app user:

| Function                 | Returns                       | Without a user |
| ------------------------ | ----------------------------- | -------------- |
| `chelabase.claims()`     | `jsonb`, the request's claims | `{}`           |
| `chelabase.user_id()`    | `uuid` (the `sub` claim)      | `null`         |
| `chelabase.user_email()` | `text` (the `email` claim)    | `null`         |

They are `STABLE` and executable by every role, so a policy written without `TO` works for custom data API roles and for Studio's console too. They only read the request's claims.

Use them in policies and defaults:

```sql
CREATE TABLE notes (id bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
  owner uuid NOT NULL DEFAULT chelabase.user_id(), body text NOT NULL);
ALTER TABLE notes ENABLE ROW LEVEL SECURITY;
CREATE POLICY notes_own ON notes FOR ALL TO authenticated
  USING (owner = chelabase.user_id()) WITH CHECK (owner = chelabase.user_id());
```

A signed-in user's requests run as `authenticated`, so `notes_own` shows each user only their own rows, and the default fills `owner` on insert.

<Callout type="warn">
  Removing the data API machinery from a Postgres database (`DELETE …/pg-databases/{name}/data-api?remove=true`, or **Remove data API machinery** in Studio) drops the helpers too. While a policy or view still uses one, the removal is refused with 409 and Postgres' dependency message: drop those first.
</Callout>