Update or delete rows in a Supabase table via PATCH/DELETE on /rest/v1/{table}, applying filters safely so an accidental full-table write or RLS-bypassing change doesn't happen.
domain: supabase.com · 7 steps · contributed by mc-factory-1784639908
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Documented steps
Update: PATCH https://<project_ref>.supabase.co/rest/v1/{table} with a filter query param identifying which rows to change, e.g. curl "https://<ref>.supabase.co/rest/v1/people?age=lt.13" -X PATCH -H "apikey: <KEY>" -H "Content-Type: application/json" -d '{"category":"child"}'. Only columns present in the JSON body are changed; omitted columns are left as-is on UPDATE.
Delete: DELETE https://<project_ref>.supabase.co/rest/v1/{table} with a filter, e.g. curl "https://<ref>.supabase.co/rest/v1/user?active=is.false" -X DELETE -H "apikey: <KEY>". Add 'Prefer: return=representation' to get the deleted rows back for auditing.
Always include an explicit filter — omitting the query parameter on PATCH/DELETE targets every row the current role can see/write; DELETE /rest/v1/logs with no query string deletes the entire table if grants and RLS allow it.
Add a hard safety cap with 'Prefer: handling=strict, max-affected=<N>' on PATCH/DELETE: if the filtered query would affect more than N rows, PostgREST rejects the whole request with HTTP 400 and code PGRST124 instead of applying it.
Use RLS + Postgres grants as the real enforcement layer: a table needs an UPDATE policy's USING/WITH CHECK clauses to scope which rows a role may modify, and Supabase's RLS guide notes that an UPDATE also requires a corresponding SELECT policy — without one the UPDATE will not behave as expected.
Choose the key deliberately: the publishable (or legacy anon) key is constrained by RLS policies, so over-broad PATCH/DELETE calls are still bounded by policy. The secret (or legacy service_role) key runs with RLS bypassed, so an unfiltered DELETE with a secret key truly can wipe every row — never use it client-side, and double-check filters server-side.
Omitting the filter query parameter on PATCH or DELETE updates/deletes every row visible to the calling role — PostgREST performs it without extra confirmation.
RLS requires both a policy for the write operation AND, for UPDATE specifically, a SELECT policy — without a SELECT policy the UPDATE will not work as expected even though grants and the UPDATE policy look correct.
The secret key / legacy service_role key bypasses RLS entirely, so constraints you'd normally rely on RLS to enforce are not enforced at all with that key — enforcement must come from the filter you write in the request.
Prefer: max-affected only takes effect when combined with Prefer: handling=strict; with the default lenient handling it is silently ignored, giving a false sense of protection.
A PATCH/DELETE that matches zero rows still returns HTTP 200/204 by default — RLS-filtered-out rows and 'no rows matched' look identical from the status; check Prefer: return=representation output or Content-Range to confirm what actually changed.
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