Compare monthly cost across Clerk, Auth0, Supabase Auth, and Firebase Auth as your user base grows. Adjust monthly active users — the estimate updates live.
Billable MAU is your monthly active users minus the selected provider's free-tier allowance, floored at zero so you're never charged below the free threshold. Monthly cost multiplies that billable MAU by the provider's per-MAU rate above the free tier.
It doesn't account for enterprise plan minimums, SSO or MFA add-on fees, or organization-based pricing that some providers apply for B2B multi-tenant apps. Treat this as a directional estimate for provider comparison, not an exact invoice.
Billable MAU is your monthly active users minus the provider's free tier, floored at zero. Monthly cost is that billable MAU multiplied by the provider's per-MAU rate. If your MAU is under the free tier, cost is $0.
Supabase bundles auth with its broader database and backend platform and prices it to attract users into the ecosystem, while Auth0 is a standalone enterprise identity product with deeper compliance and customization features baked into its cost.
Most providers count a MAU as any user who authenticates or has an active session at least once within a rolling 30-day window, regardless of how many times they log in during that period.
Payment processor fees · API gateway cost · AI coding tool cost · Compare: Clerk vs Auth0