Auth0 Pricing Calculator: Compare Clerk and Firebase

How each provider counts users

Most providers bill monthly active users, but they draw the line in different places. Auth0 counts any external user who authenticated during the month on a tenant. Identity Platform counts any account that signed in during the month and stores inactive accounts for free. WorkOS counts a user who did anything in the calendar month, a profile update included. Cognito counts a user once they are active in the month on a given pricing tier.

Clerk is the exception. It bills monthly retained users: people who come back at least a day after they signed up. A launch that brings in thousands of curious sign-ups who never return costs nothing on Clerk, and the same month is billed in full elsewhere. The calculator treats your active users as retained, so it overstates Clerk for an app with a long tail of one-visit accounts.

What forces an upgrade

The user count is rarely the only driver. Two features move most apps onto a paid plan:

• MFA. Clerk includes it only on Pro, and Auth0 adds authenticator-app MFA on Essentials. Firebase needs the upgrade to Identity Platform. Supabase, WorkOS, Cognito Lite and Stytch include authenticator-app MFA. Cognito bills SMS codes through Amazon SNS, Stytch passes them through at cost, and Supabase sells phone MFA as an add-on.
• Enterprise SSO. Clerk and WorkOS price each SAML or OIDC connection, and Stytch includes a few before it does. Auth0's Free plan allows an enterprise connection, but its paid B2C plans leave them out, so SSO on a paid plan means its B2B plans. Supabase, Firebase and Cognito bill each user who signs in through SAML or OIDC, which depends on your customers' headcount, not on how many connections you have.

Smaller limits push teams up too: removing the provider's branding, separate production and development environments, log retention and custom domains. Read the plan pages for those before you commit.

Graduated, stepped and blocked prices

Providers turn a user count into a price in three ways, and the shape matters as much as the rate.

Graduated prices, used by Clerk, Identity Platform, Cognito Lite and Supabase's overage, charge each band's rate only for the users inside that band. Growing by one user adds one user's cost, and the average cost per user falls as you grow.

Stepped prices, used by Auth0's self-serve plans, charge the price of the smallest step that covers your count. One user over a step boundary moves the whole bill to the next step, so a count just above a boundary is the most expensive place to be.

Blocks, used by WorkOS past its free allowance, charge for each started block. The first user of a new block costs as much as the whole block.

What the totals leave out

Each total covers one production environment. It leaves out SMS for phone sign-in and MFA, which several providers charge per message, and the per-user tiers for SAML and OIDC sign-ins where a provider bills them that way. Add-ons such as custom domains, phone MFA, bot protection and audit log streaming are extra where a provider sells them. Enterprise plans and annual commitments are negotiated, so a large account may pay less than the published rate.