01Read the write response
Capture status, Supabase error code, message, table, and operation.
What the result tells you: A 403 or 42501 is authorization; a successful response with stale UI is state or query invalidation.
ERR-751/Lovable + Supabase · Data not saving / 403 / RLS
Appears when: Data not saving / 403 / RLS
Lovable and Supabase data is not saving
The UI may be optimistic even when the database write is rejected. Inspect the actual insert or update response, then verify the session, target table, payload ownership fields, and RLS policy instead of assuming the form submission succeeded.
How do I fix lovable and supabase data is not saving?
01
# Make write failures visibleShow a truthful error state and keep the returned code in logs.02
# Define ownership server-sideDerive trusted user or tenant identity from the authenticated context.03
# Correct the operation-specific policyRepair INSERT or UPDATE permissions without opening unrelated rows.04
# Read the saved record backVerify persistence after refresh and under the same RLS context.Preserve the current working revision, change one proven boundary, and verify the published path in a clean session.
What if the quick fix does not work?
02Inspect session and payload
Confirm the user id and tenant fields in the proposed row match the authenticated context.
What the result tells you: Null or client-supplied ownership values commonly conflict with RLS.
03Compare INSERT and UPDATE policies
A form may create on first use and update later; those are separate policy decisions.
What the result tells you: One operation can work while the other is legitimately denied.
| Likely cause | What proves it | First safe action |
|---|---|---|
| Write error is hidden by the UI | A 403 or 42501 is authorization; a successful response with stale UI is state or query invalidation. | Make write failures visible |
| RLS ownership mismatch | Null or client-supplied ownership values commonly conflict with RLS. | Define ownership server-side |
| Only one operation is allowed | One operation can work while the other is legitimately denied. | Correct the operation-specific policy |
| Wrong project or table | A 403 or 42501 is authorization; a successful response with stale UI is state or query invalidation. | Read the saved record back |
Why do AI-built apps hit this problem?
The UI may be optimistic even when the database write is rejected. Inspect the actual insert or update response, then verify the session, target table, payload ownership fields, and RLS policy instead of assuming the form submission succeeded.
Write error is hidden by the UI
The generated form reports success without checking the returned error.
RLS ownership mismatch
The row user or tenant field does not satisfy the active policy.
Only one operation is allowed
INSERT exists but UPDATE does not, or the reverse.
When the built-in AI fix makes it worse
Freeze generated changes, restore the last known working version, reproduce one request, collect the browser and platform logs, and change one layer at a time.
How do I stop this problem recurring?
- →Never show a success state before the write response is checked.
- →Test create, edit, refresh, and cross-user access for each critical record.
- →Keep production configuration in an explicit release checklist, not in chat history.
- →Test the published URL in a clean browser session before calling the release complete.
- →Keep a last-known-good deployment and a documented rollback step.
- →Log the critical request path with enough context to identify the failing layer.
Still stuck with lovable and supabase data is not saving?
AI prototype hardeningWe restore the critical path and document the root cause.
- Production failure reproduced with evidence
- The smallest responsible layer repaired
- Rollback and prevention guidance included
Lovable and Supabase data is not saving questions
Why does Lovable show success when nothing was saved?+
The interface may update optimistically or ignore the database error. The network response is the source of truth.
Can INSERT and UPDATE need different policies?+
Yes. RLS evaluates operation-specific rules, and updates also interact with row visibility.
Should the browser choose tenant_id?+
Do not trust arbitrary ownership from the browser. Validate or derive tenant identity from authenticated membership.