How to Debug RLS in Supabase (Simple Troubleshooting Guide)

Introduction — How to Debug RLS in Supabase Without Guessing

If you’ve ever turned on Row Level Security and watched your app collapse with mysterious errors… you’re not alone. Understanding how to debug RLS in Supabase is almost a required skill once you start handling authenticated reads and writes.

Common errors look like this:

“new row violates row-level security policy”
“permission denied for table”
“select denied by RLS policy”
“null value violates RLS check constraint”

These errors don’t tell you what’s wrong—only that Supabase blocked the action.

This guide will show you exactly how to debug RLS in Supabase, why these errors happen, and how to fix them quickly—whether you write code manually or use AI tools like Lovable, Bolt.new, v0, Cursor, or PromptXL.

Why Debugging RLS in Supabase Feels Confusing

Row Level Security doesn’t fail where you expect. Your UI may work and your API may run, but the database silently rejects the operation.

That’s because Supabase checks:

Authentication
Ownership fields
Policy logic
Requested action (SELECT / INSERT / UPDATE / DELETE)
API key permissions

When one piece doesn’t match expectations, RLS intervenes and stops the request.

Learning how to debug RLS in Supabase means identifying which layer is blocking the action.

Step 1 — Debug Authentication in Supabase RLS

The most common RLS failure is:
The request is not authenticated.

Run this SQL:

select auth.uid();

If you see a UUID, authentication is working.
If you see NULL, your request has no authentication attached—meaning RLS will block everything.

If it’s NULL, check:

Are you logged in?
Is your Supabase client initialized correctly?
Are you using the correct key? (anon vs service_role)

This is the first step when learning how to debug RLS in Supabase because nothing works without an identity.

Step 2 — Check Ownership Columns When Debugging RLS in Supabase

RLS policies compare the logged-in user to the row owner. That usually means the table must include:

user_id uuid references auth.users(id);

To confirm, run:

SELECT * FROM your_table LIMIT 1;

If user_id is missing, policies will fail—even if they exist.

This is one of the most common issues developers discover while learning how to debug RLS in Supabase.

Step 3 — Verify if RLS Is Enabled or Disabled in Supabase

Run:

select relrowsecurity from pg_class where relname = 'your_table';

TRUE → RLS is ON
FALSE → RLS is OFF

Sometimes developers enable RLS too early—or forget they disabled it.

Knowing this helps you debug confidently.

Step 4 — Review Policies While Debugging RLS in Supabase

Next, check active policies:

select * from pg_policies where tablename = 'your_table';

Ask yourself:

Is there a policy for SELECT?
Is there a policy for INSERT?
Is there a policy for UPDATE?
Is there a policy for DELETE?

Missing even one operation causes failure.

A core part of learning how to debug RLS in Supabase is identifying missing or incomplete policy coverage.

Step 5 — Use Supabase Tools to Debug RLS Policies

Supabase includes a built-in testing environment:

Open Table Editor
Select a table
Open Policies
Use Preview & Test

You can simulate:

Anonymous user
Authenticated user
Service-level access
Custom role behavior

This feature makes it much easier to learn how to debug RLS in Supabase without guessing.

Step 6 — Confirm Key Usage While Debugging Supabase RLS

Different keys behave differently:

Key Type	Result
`anon`	Must follow RLS
`authenticated`	Must follow RLS
`service_role`	Bypasses RLS completely

If an operation works in SQL or Dashboard, but fails in your app—it’s almost always a key mismatch.

Step 7 — Test CRUD Operations to Debug RLS Behavior

To isolate issues, test one action at a time:

🟦 SELECT

select * from your_table;

🟩 INSERT

insert into your_table (...) values (...);

🟧 UPDATE

update your_table set ... where id = ...;

🟥 DELETE

delete from your_table where id = ...;

If one fails, the policy for that action is missing or wrong.

Step 8 — Fix Policy Logic While Debugging RLS in Supabase

When in doubt, test with a clean rule:

(user_id = auth.uid())

Avoid:

Nested CASE expressions
Hard-coded user IDs
Missing WITH CHECK clauses

Simplicity wins, especially while learning how to debug RLS in Supabase.

Common Mistakes When Debugging RLS in Supabase

🚫 No WITH CHECK for INSERT/UPDATE
🚫 Testing logged out
🚫 Wrong casing (userID vs user_id)
🚫 Missing user_id field
🚫 Wrong Supabase key

Spotting these saves hours.

Final Summary — How to Debug RLS in Supabase Successfully

To resolve RLS issues, follow this flow:

Verify authentication
Confirm the ownership column
Check if RLS is enabled
Review existing policies
Test using the built-in debugger
Confirm key usage
Test CRUD individually
Simplify your policies

Once you master how to debug RLS in Supabase, your development workflow becomes more predictable and secure.

Build Without RLS Stress — Try PromptXL

Instead of fixing RLS after everything breaks, PromptXL builds Supabase apps correctly from the start with:

✔ Auto-generated policies
✔ Proper user_id mapping
✔ Multi-tenant organization structure
✔ Production-ready access controls
✔ Supabase-aware AI models

How to Debug RLS in Supabase (Simple Troubleshooting Guide)

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