Auth tools for AI-built apps
Sign-up, login, sessions and social sign-in without writing it from scratch. 4 options, each with its free plan and the catch.
Every auth option
Clerk
Drop-in authentication and user management with prebuilt sign-in, sign-up and profile UI components. Bills on monthly retained users instead of raw sign-ups.
Free Hobby: free, no credit card required Auth0
Okta's hosted identity platform: universal login, social and passwordless sign-in, organizations and enterprise connections.
Free Free plan: up to 25,000 monthly active users, no credit card to sign up Supabase Auth
The auth service built into every Supabase project: email/password, magic links, OAuth providers and anonymous sign-ins, tied directly to Row Level Security.
Free 50,000 monthly active users on the Free plan Better Auth
An open-source TypeScript authentication framework that runs inside your own app and database. Plugins add 2FA, passkeys, magic links, organizations, SSO and more.
Free Open-source library: no per-user fees when self-hostedFree tiers side by side
The first two lines of each free plan, and the price where paid plans start.
| Tool | Free plan | Paid from |
|---|---|---|
| Clerk | Hobby: free, no credit card required; 50,000 monthly retained users per app | Pro: $25/month ($20/month billed annually) |
| Auth0 | Free plan: up to 25,000 monthly active users, no credit card to sign up; Unlimited social connections, passwordless and passkeys | Essentials (B2C): from $35/month |
| Supabase Auth | 50,000 monthly active users on the Free plan; Social OAuth providers, anonymous sign-ins, basic MFA | Included in Supabase Pro (from $25/month) |
| Better Auth | Open-source library: no per-user fees when self-hosted; Works with Next.js, Nuxt, SvelteKit, Astro, Hono and more | See the pricing page |