Do these 3 things before closing this tab:
1Scan for outdated or missing drivers - takes under a minute2Clear out junk files and repair common Windows errors3Fix the driver behind crashes, sound loss and screen glitchesThe recurring Supabase Row Level Security (RLS) mistake is treating a policy—or the RLS toggle—as the whole security setup. It isn’t. SQL grants decide whether a database role may perform an operation on an object; RLS policies decide which rows that role may reach. A frontend app needs both configured deliberately, then tested for allowed and denied behavior.
In my reviews, I keep seeing developers stop after adding a policy and assume the app is protected. That observation describes the apps I have reviewed, not a measured rate across all vibe-coded apps. Supabase’s own documentation makes the underlying distinction clear: authorization depends on the full path from exposed object and role to grants, policy conditions, and any alternate access route.
As an Amazon Associate I earn from qualifying purchases.
What the common RLS mistake actually is
Row Level Security is not a substitute for SQL privileges. Think of authorization as two gates:
Recommended Free Tools
- Grants: may this database role perform an operation—such as
SELECT,INSERT,UPDATE, orDELETE—on this table or other object? - RLS policies: if the role has that privilege, which rows may it read or change?
A policy does not revoke an existing grant. Conversely, a grant does not by itself make every row accessible when RLS is enabled and applicable policies restrict access. Supabase explains the distinction in its API security guide and RLS documentation.
#1 Best Overall
This is why “I turned RLS on” and “I added a policy” are not proof that the intended boundary exists. You must check the actual role, operation, object privileges, policy conditions, and other routes through which the data can be reached.
Make the policy match the person and the action
For a basic private-records table, Supabase’s example ties each row to the signed-in user. A policy for a personal todos table can target the authenticated role and compare the row’s user_id with the current user ID, using a condition such as (select auth.uid()) = user_id. See Supabase’s RLS examples.
The important part is not copying that expression into every app. It is making the rule express the app’s real authorization model. An organization app may need membership checks; a shared document may allow several named users; an admin workflow may need a separate, tightly controlled path. A condition such as using (true) is appropriate only when every row really is meant to be available to the policy’s specified role.
Review policies per operation. A rule that allows a user to read their own row does not automatically define who may insert a row, which rows may be updated, or whether deletion is permitted. Match each role and operation to the intended behavior rather than assuming one policy covers every action.
Audit the whole exposed surface, not just base tables
Start with every object reachable through an exposed schema or the Data API, then account for product-specific access paths. Supabase’s API security guide and RLS guide call out cases that a quick table-policy check can miss:
- Views: views can bypass underlying RLS by default. Inspect their security behavior and who is allowed to query them.
- Functions: functions are not protected by table RLS in the same way. Review their code, any
SECURITY DEFINERbehavior, and theirEXECUTEgrants carefully. - Product boundaries: a pre-request check configured for the Data API does not automatically protect Realtime, Storage, or other Supabase products. Review the authorization mechanism for each surface the app uses.
- Schema exposure: inventory which schemas and objects are exposed, not only the tables you remember creating.
RLS remains valuable, but it only governs the paths and objects to which it applies. An exposed view or a privileged function can change the effective boundary even when the underlying table policy looks sensible.
Check grants instead of assuming their defaults
Some existing Supabase projects may have default privileges that grant access to public-schema tables for roles such as anon, authenticated, and service_role. Defaults can vary, and Supabase describes a shift toward opt-in exposure. Do not infer your project’s current privileges from a tutorial or from the fact that a policy exists; inspect the actual grants and configure least privilege for the objects and operations you expose. The relevant guidance is in Securing your API.
The Tool Desk
Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →Keep grants and RLS changes in migrations so the setup is repeatable across environments and deployments. Supabase’s table setup and testing workflow covers explicit grants, policies, and database tests.
Know what your API key does—and does not do
A publishable key (or the older anon key) may appear in frontend code. It identifies the project; it does not make the underlying data safe by itself. Frontend access depends on appropriate grants and RLS policies for the role used by the request. Supabase sets out the conditions in Securing your data and explains key roles in its API keys guide.
Secret and service-role keys are different: they bypass RLS and belong only in trusted server-side components, never in browser code. Supabase states, “Never expose your service role or secret keys on the frontend.” If a service-role client unexpectedly receives RLS errors or returns no data, check whether a user-session Authorization header is overriding the service-role request; Supabase discusses that specific issue in its service-role troubleshooting guide.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Test both access and denial
A dashboard toggle tells you that a setting changed; it does not establish that your application’s rules produce the intended outcomes. Supabase’s documented workflow tests positive and negative cases, including relevant anon and authenticated roles. Its RLS guide puts the point plainly: “Until the suite passes, you don’t know whether the policies do what you intended.”
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
- Inventory exposed tables, views, and functions, and list the roles and operations the app needs.
- For every table, confirm RLS is enabled where needed and map each policy to its role, operation, and row condition.
- Inspect grants separately; remove privileges that are broader than the app requires.
- Test expected access—for example, a signed-in user reading their own record—and expected denial, such as a different user attempting to read or change it.
- Cover relevant operations: select, insert, update, and delete. Include alternate access paths and roles used by the application.
- Run the database test suite with
supabase test db, and keep schema, grant, and policy changes reproducible in migrations.
Debug errors by separating the gates. Supabase notes that missing grants can produce a permission error before policy evaluation, while a policy that matches no rows can yield an empty result. An empty response therefore does not, by itself, tell you which layer is responsible. See the API keys troubleshooting guidance.
Use Security Advisor findings as leads, not a safety certificate
Supabase’s Advisors documentation lists findings that include RLS disabled, RLS enabled without policies, permissive or multiple permissive policies, and sensitive columns exposed, among other hazards. The production checklist also directs teams to review RLS and Security Advisor findings.
Work through the findings, resolve them or consciously assess why they are acceptable, and still test the application’s authorization behavior. The documented findings are useful configuration signals; a clean report is not described as formal proof that every app-specific authorization rule is correct.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
