Comparison
Clerk vs Supabase Auth vs Auth0
Short answer. Use the auth system the project already calls. Clerk and Auth0 identify users and do not store your app's tables. Supabase Auth sits next to those tables, and Row Level Security is what checks the user id. Their free-tier numbers count different kinds of users, so 50,000 in one vendor's docs is not 50,000 in another's.
Lovable, Bolt, Cursor, v0, and Replit will happily add a sign-in screen. That screen is not the same decision as who may read a row. This comparison uses each vendor's public pricing and docs as checked on 19 Oct 2026. Auth0 is not a directory listing here. The Auth0 column links to Auth0's pricing page.
Updated 19 Oct 2026
| Question | Clerk | Supabase Auth | Auth0 |
|---|---|---|---|
| What you are turning on | Hosted sign-up, sign-in, sessions, and user profile UI, with APIs and components for a React or Next.js app. | Authentication inside the Supabase project that also holds Postgres, storage, and row level security. | An identity service with its own tenants, organizations, and connections. Your app's database stays wherever you put it. |
| Who may read a row | Your database. Clerk's session tells you who signed in. If the rows live in Supabase, the policies have to trust that identity. Clerk does not apply the policies. | Row Level Security, usually with auth.uid(). A table with RLS off, or a policy of true, ignores the sign-in screen. | Your database or API. Auth0 issues the login. It does not ship the tables the generated app is reading. |
| How a user is counted | Monthly retained users. Clerk's pricing page defines one as a user who visits in a month at least one day after signing up. A person who signs up and never returns is not billed. | Monthly active users on the Supabase plan. The pricing page lists the quota. It does not use Clerk's retained-user definition. | Monthly active users. Auth0 defines one as any non-employee user who authenticated during the month for that tenant. |
| Published price, 19 Oct 2026 | Hobby is free and includes 50,000 monthly retained users per app. Pro is $25/month, or $20/month billed annually, with 50,000 included and then volume pricing. Business is $300/month, or $250/month annually. | Included in the Supabase plan. Free includes 50,000 monthly active users. Pro starts at $25/month and includes 100,000, then $0.00325 per MAU. The plan also covers the database, not only auth. | Free is $0 for up to 25,000 monthly active users, the same for B2C and B2B, with no credit card to sign up. Essentials starts at $35/month for B2C or $150/month for B2B, at 500 MAU. Professional starts at $240/month for B2C or $800/month for B2B, at 500 MAU. Between tiers, Auth0 bills the next tier up. Yearly billing is 11 times the monthly price. |
| Sign-in UI and extra features on the entry paid plan | Prebuilt sign-in components are the product on every plan, including Hobby. The Pro feature list adds multi-factor authentication and one SSO connection. | The sign-in flow lives in the same project as the tables. A signed-in request reaches Row Level Security as the authenticated role, and policies can check auth.uid(). | Hosted login is the product. The Free plan includes passwordless auth, five organizations, one enterprise connection, self-service SSO, and SCIM. Pro MFA factors are listed from Essentials upward, not on Free. |
| The miss in a generated app | The app knows the Clerk user id and still queries every row, because nothing in the database checks that id. | RLS is off, or a policy uses true for anon. The sign-in form can be perfect and the table is still public. | The app stores an access token and treats that as permission to read other people's records from your own API. |
Lean toward Clerk when
You want hosted sign-in UI in a React or Next.js app, and you will still teach your database which user owns each row. Pro is the first plan whose published list includes MFA.
Lean toward Supabase Auth when
The builder already created Supabase Auth and the tables can use auth.uid(). Adding a second login vendor is a migration. Close the policies first. The Supabase checklist is linked below.
Lean toward Auth0 when
You need the B2B pieces on Auth0's published Free or Essentials plans, such as organizations and an enterprise connection, and you accept MAU tier pricing. You still bring your own database.
For a vibe-coded app that already signs people in, keep that provider and spend the afternoon on authorization. Add Clerk or Auth0 when the sign-in product itself is missing, and write down how the user id reaches the database. Prices above are the vendors' published starting figures on 19 Oct 2026, not a quote.
Related on ShipSafeStack
FAQ
Does Clerk replace Supabase?
No. Clerk is authentication and user management. Supabase is the Postgres project, and Supabase Auth is the login that ships inside it. You can use Clerk in front of a Supabase database only if the database policies accept the Clerk identity. The rows are still yours to protect.
Are 50,000 free users the same on Clerk and Supabase?
No. Clerk's Hobby plan includes 50,000 monthly retained users per app, and Clerk counts a user only after they return at least a day after signup. Supabase's Free plan includes 50,000 monthly active users for the whole project. Auth0's Free plan includes up to 25,000 monthly active users, defined as non-employee users who authenticated that month.
Is Auth0 a directory listing on ShipSafeStack?
No. This page compares Auth0 from its public pricing page because people building with AI tools ask about it alongside Clerk and Supabase Auth. The Clerk and Supabase columns link to their directory pages. The Auth0 column links to Auth0.
Which one should a Lovable or Bolt project use?
The one the project already uses. Lovable Cloud and many Bolt databases are already on a Supabase-style backend, so Supabase Auth is often already in the project. Switching the login screen without updating row policies leaves the data on the old rules.
Sources
Checked 19 Oct 2026. Plan names and prices change. Open the current page before you buy.
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