Authentication
Sign-up, login, password reset and social login. Usually priced by monthly active users.
Monthly cost as you grow
For a commercial project, using the cheapest plan that fits at each size and our default usage averages. How we estimate
| Provider | 100 users | 1,000 users | 10,000 users | 100,000 users |
|---|---|---|---|---|
| Auth0 | $0Free | $0Free | $0Free | $0no plan fits |
| Clerk | $0Free | $0Free | $0Free | $1,025Pro |
| Firebase Authentication | $0Spark (no-cost) | $0Spark (no-cost) | $0Spark (no-cost) | $275Blaze (Identity Platform) |
| Kinde | $0Free | $0Free | $0Free | $1,534Plus |
| WorkOS AuthKit | $0User Management | $0User Management | $0User Management | $0User Management |
Free tiers and their catches
Auth0
Free: Past 25,000 active users Auth0 says you must pick a paid plan with a higher user allowance.
- Free stops at its limits rather than billing more.
Clerk
Free: Clerk counts monthly retained users: a user counts once they return 24 hours or more after signing up. This estimate uses active users, which can only overstate it.
- Free stops at its limits rather than billing more.
Firebase Authentication
Spark (no-cost): No payment method needed. Phone sign-in is not available on Spark.
- Spark (no-cost) stops at its limits rather than billing more.
Kinde
Free: Uncapped users is listed as a Pro feature, so the Free plan is capped at 10,500. The page does not say exactly what happens at the cap.
- Free stops at its limits rather than billing more.
WorkOS AuthKit
User Management: Free for the first 1 million active users a month. A user is active if they sign up, sign in or update their profile in that calendar month.
- User Management needs a payment card to sign up.