Lovable and Supabase data not saving: what to check

Start by identifying the exact failure

Do not begin by changing the whole form. First confirm whether the app sends a request, whether Supabase accepts it, and whether the saved row can be read back. Those are three different problems with different fixes.

Open the browser developer tools, submit one controlled test, and inspect the network request and console. Record the signed-in user, values submitted, response status, and any Supabase error message. A precise error such as a policy violation, missing column, invalid type, or null constraint is much more useful than the visible symptom alone.

• Does clicking Save trigger a network request?
• Is the request an insert, update, or upsert?
• What status and error message come back?
• Does the row appear in the correct Supabase table?
• Can the same user read the row after a refresh?

Confirm the user session before saving

Many Lovable and Supabase apps attach data to the authenticated user's ID. If the session has expired, is still loading, or is not available when the form submits, the request may send a null owner ID or run as an anonymous user.

Check that the app waits for authentication to finish, reads the current user from the active session, and uses that same ID in the row being created or updated. If a profile table is involved, confirm that the profile row exists and is linked to the authentication user you are testing.

Check the table, columns, and values

Compare the form payload with the live database schema. Column names, required fields, foreign keys, enum values, and data types must match. A field renamed in the interface but not in Supabase can break a previously working flow.

Pay special attention to empty strings, dates, numbers, arrays, and optional fields. An empty input may need to become null, while a numeric field may still arrive as text. For updates, confirm the query filters the intended row instead of matching nothing.

• Every payload key exists as a column in the live table
• Required columns receive a value or a database default
• Foreign-key values point to existing rows
• The update filter matches exactly one intended record
• Development and production use the same expected schema

Review Row Level Security policies

Supabase Row Level Security, usually called RLS, controls which rows each user can select, insert, update, or delete. A policy that permits reading does not automatically permit inserting or updating. The operation must have a matching policy and its condition must be true for the submitted row.

For user-owned records, the insert policy commonly checks that the row's owner ID equals the authenticated user's ID. The update policy may also need a rule for both the existing row and the new row. Review policies in Supabase and test with a normal signed-in account rather than only with privileged dashboard access.

Make the save flow honest and recoverable

The interface should prevent repeat submissions while a request is running, display the returned error in plain language, and preserve the user's input when saving fails. After success, either update the local state from the returned row or fetch the saved data again.

If the page refreshes immediately after submission, it can interrupt the request or make a failed save look like a reset. Await the database call, handle its error, then navigate or refresh only after a confirmed result.

Compare preview and production settings

If saving works in preview but fails on the live site, compare the Supabase URL, public key, redirect URLs, and allowed origins used by each environment. Confirm that production is connected to the intended Supabase project and that its database contains the same migrations and policies.

Retest the live site in a private browser window with a fresh user. This catches missing sessions, cached state, and permissions that an administrator account may not reveal.

• Production points to the intended Supabase project
• Required environment values exist in production
• Authentication redirect URLs include the live domain
• The live database has the current tables and policies
• A normal user can save, refresh, and see the same data

When a focused repair is faster

If several forms fail, policies are unclear, or preview and production behave differently, the problem may cross the frontend, authentication, and database layers. A focused review should reproduce one failure, trace the full request, fix the responsible layer, and then retest connected flows.

That approach is safer than repeatedly asking an AI builder to rewrite the page without first identifying why Supabase rejected or lost the data.