Free Authentication & User Management
Discover 26+ free authentication & user management tools and services for developers. All resources include generous free tiers or are fully open-source.
Free tier limits, side by side
Checked6 of 6 authentication & user managemententries below have had their actual quotas read off the vendor's own pricing page. Each row links to the page the numbers came from, with the date they were read.
| Service | Free MAU | Organizations / tenants | Apps & connections | Other caps |
|---|---|---|---|---|
| Auth0 · source | 25,000 | 5 organizations | Unlimited social connections, 1 enterprise connection, 1 custom domain | 1-day log retention, 1,000 machine-to-machine tokens |
| Clerk · source | 50,000 monthly retained users per app | 100 monthly retained organizations per app | 3 social connections, custom domain | 3 dashboard seats, 5 user impersonations |
| Firebase Auth · source | 50,000 (Identity Platform) | Not published | Not published | 50 MAU for SAML/OIDC sign-in |
| Supabase Auth · source | 50,000 | Not published | Not published | 500 MB database, 1 GB file storage, 5 GB egress; projects pause after 1 week idle, 2 active projects |
| Logto · source | 50,000 | Not published | 3 applications, 1 machine-to-machine app, 3 social connectors | Not published |
| Permit.io · source | 1,000 | 20 tenants | Not published | 3 environments, 25 roles, unlimited authorization queries |
Free tiers change without notice. Figures are what the vendor published on the date shown — check the source link before you commit to one.
Auth0
Free up to 25,000 monthly active users and unlimited logins. Universal login, MFA, social login.
Clerk
Authentication and user management. Free: 50,000 monthly retained users per app.
Firebase Auth
Free authentication service: 10K verifications/mo phone auth, unlimited email/password.
Supabase Auth
Open-source auth with row-level security. 50K monthly active users free.
Logto
Open-source auth infrastructure. Free: up to 50K MAU, social connectors, RBAC.
Permit.io
Authorization as a service. Free: up to 1,000 monthly active users.
Compare these head to head
Deeper write-ups on tools listed above — pricing, trade-offs and a verdict.