APIbenchmarks

Category report · 8 providers evaluated

Best Authentication & Identity APIs

Authentication & Identity APIs handle the hard, security-critical work of signup, login, sessions, MFA, social/passwordless login, and enterprise SSO/SCIM so product teams don't have to. The category splits into incumbents built for enterprise IAM (Okta, and Auth0 which Okta now owns), B2B-enterprise-readiness specialists (WorkOS, Frontegg, Stytch), developer-experience-first drop-ins (Clerk), and auth bundled inside a broader backend-as-a-service (Firebase, Supabase). Compare on documentation/DX quality and quickstart speed, reliability (published SLA, status-page history, proven scale), breadth and quality of official SDKs and framework support, and how fast a developer or AI agent can self-serve a working key. Free-tier generosity now clusters around 50k MAU for the developer-friendly tools, while enterprise-grade SSO is typically priced per connection or gated behind sales.

Auth0 logo
Highest rated
Auth0

Full-featured CIAM for B2C and B2B

91.7
ABI
A
VerdictWhat is the best authentication & identity API?The short answer, plus which provider wins on each axis.Read the verdict →

What is the best Authentication & Identity API?

#ProviderDocumentationReliabilityEcosystemAccessibilityABIFree
1Auth0 logoAuth0Okta9392958591.7AYes
2Firebase Authentication logoFirebase AuthenticationGoogle8590888887.6AYes
3WorkOS logoWorkOSWorkOS9084829086.5AYes
4Clerk logoClerkClerk9178809285.2AYes
5Stytch logoStytchStytch8678769082.3BYes
6Supabase Auth logoSupabase AuthSupabase8476809082.2BYes
7Okta Customer Identity logoOkta Customer IdentityOkta8093854878.1BNo
8Frontegg logoFronteggFrontegg7875728276.6BYes

Table 1. Best Authentication & Identity APIs ranked by the APIbenchmarks Index. Specification columns are vendor-stated; ABI is computed per the published methodology.

Composite scores

Auth0
91.7
Firebase Authentication
87.6
WorkOS
86.5
Clerk
85.2
Stytch
82.3
Supabase Auth
82.2
Okta Customer Identity
78.1
Frontegg
76.6
Scale 0–100. Highest in category: 91.7.

Figure 1. APIbenchmarks Index for Authentication & Identity APIs, bar length proportional to composite score; colour encodes letter grade.

Provider scorecards

Auth0 logo
1. Auth0AABI 91.7 · Excellent

The category-defining developer-first identity platform, now Okta-owned, with deep docs, extensibility (Actions/Rules) and a 99.99% public-cloud SLA.

Documentation & DX
93
Reliability
92
Ecosystem & SDKs
95
Accessibility
85
Firebase Authentication logo
2. Firebase AuthenticationAABI 87.6 · Excellent

Google's BaaS-bundled auth with massive scale and SDKs across every mobile/web platform; free to 50k MAU, with Identity Platform for enterprise SSO.

Documentation & DX
85
Reliability
90
Ecosystem & SDKs
88
Accessibility
88
WorkOS logo
3. WorkOSAABI 86.5 · Excellent

Enterprise-readiness APIs (SSO, SCIM Directory Sync, Audit Logs, AuthKit) with a famously generous free tier and clean per-connection pricing for B2B SaaS.

Documentation & DX
90
Reliability
84
Ecosystem & SDKs
82
Accessibility
90
Clerk logo
4. ClerkAABI 85.2 · Excellent

DX-obsessed drop-in auth with prebuilt UI components and best-in-class Next.js/React SDKs; 50k free monthly-active users and frictionless self-serve.

Documentation & DX
91
Reliability
78
Ecosystem & SDKs
80
Accessibility
92
Stytch logo
5. StytchBABI 82.3 · Strong

API-first passwordless and B2B auth with no feature gates on the free tier (MFA, SSO, SCIM, RBAC, M2M, device fingerprinting all included) and usage-based pricing.

Documentation & DX
86
Reliability
78
Ecosystem & SDKs
76
Accessibility
90
Supabase Auth logo
6. Supabase AuthBABI 82.2 · Strong

Open-source Postgres-native auth (GoTrue) bundled with the Supabase backend, with row-level-security integration and a generous 50k-MAU free tier.

Documentation & DX
84
Reliability
76
Ecosystem & SDKs
80
Accessibility
90
Okta Customer Identity logo
7. Okta Customer IdentityBABI 78.1 · Strong

The enterprise IAM incumbent's CIAM offering, built for scale, compliance and 99.99% enterprise SLAs, but sales-gated and priced for large deployments.

Documentation & DX
80
Reliability
93
Ecosystem & SDKs
85
Accessibility
48
Frontegg logo
8. FronteggBABI 76.6 · Strong

B2B user-management platform shipping multi-tenancy, admin portal, RBAC and audit logs in the SDK; self-serve with a 7,500-MAU free tier.

Documentation & DX
78
Reliability
75
Ecosystem & SDKs
72
Accessibility
82

Frequently asked questions

What is the best Authentication & Identity API?
By the APIbenchmarks Index, Auth0 rates highest (ABI 91.7, grade A). Full-featured CIAM for B2C and B2B The ABI weights documentation, reliability, ecosystem, and accessibility; price is reported separately, so the right pick still depends on your budget and workload.
Which authentication & identity APIs have a free tier?
Auth0, Firebase Authentication, WorkOS, Clerk, Stytch, Supabase Auth, Frontegg offer a free tier or trial credits.
How is the APIbenchmarks Index calculated?
The ABI is a weighted composite of four dimensions scored on absolute reference scales: documentation & DX (30%), reliability (25%), ecosystem & SDKs (25%), and accessibility (20%). Price is excluded from the composite because price units are not comparable across categories. The full formula is on the methodology page.

Popular comparisons

Auth0 vs Firebase AuthenticationAuth0 vs WorkOSAuth0 vs ClerkFirebase Authentication vs WorkOSFirebase Authentication vs ClerkWorkOS vs Clerk

References

  1. https://auth0.com/pricing
  2. https://auth0.com/docs/troubleshoot/customer-support/services-level-descriptions
  3. https://auth0.com/blog/auth0-guarantees-99-99-availability-on-public-cloud/
  4. https://status.auth0.com/
  5. https://auth0.com/docs/libraries
  6. https://www.g2.com/products/auth0/reviews
  7. https://ssojet.com/blog/auth0-complaints-reddit-developers
  8. https://securityboulevard.com/2025/09/top-10-auth0-complaints-developers-post-on-reddit-analysed/
  9. https://ssojet.com/blog/auth0-pricing-growth-penalty
  10. https://firebase.google.com/docs/auth/
  11. https://cloud.google.com/identity-platform/pricing
  12. https://cloud.google.com/identity-platform/sla
  13. https://firebase.google.com/docs/libraries
  14. https://www.metacto.com/blogs/the-complete-guide-to-firebase-auth-costs-setup-integration-and-maintenance
  15. https://www.g2.com/products/firebase-authentication/reviews
  16. https://groups.google.com/g/firebase-talk/c/BeXc-uoqYHg
  17. https://docs.cloud.google.com/identity-platform/docs/product-comparison
  18. https://www.capterra.com/p/160941/Firebase/reviews/
  19. https://workos.com/pricing
  20. https://workos.com/legal/sla
  21. https://workos.com/changelog/99-99-availability-for-sso-directory-sync-and-audit-logs
  22. https://status.workos.com/
  23. https://www.g2.com/products/workos/reviews
  24. https://compile7.org/decompile/workos-review-promise-pitfalls
  25. https://statusgator.com/services/workos
  26. https://github.com/workos/workos-node
  27. https://www.infisign.ai/reviews/workos
  28. https://clerk.com/pricing
  29. https://clerk.com/blog/new-pricing-plans
  30. https://clerk.com/docs/reference/overview
  31. https://status.clerk.com/
  32. https://clerk.com/blog/2026-03-10-service-outage-postmortem
  33. https://statusgator.com/services/clerk
  34. https://www.g2.com/products/clerk-dev/reviews
  35. https://news.ycombinator.com/item?id=41927236
  36. https://github.com/clerk/clerk-sdk-go
  37. https://stytch.com/pricing
  38. https://status.stytch.com/
  39. https://stytch.com/blog/stytch-self-serve-pricing/
  40. https://stytch.com/blog/why-switch-to-stytch/
  41. https://stytch.com/docs/sdks
  42. https://www.g2.com/products/stytch/reviews
  43. https://fusionauth.io/guides/stytch-alternatives
  44. https://supertokens.com/blog/stytch-pricing
  45. https://supabase.com/pricing
  46. https://supabase.com/docs/guides/auth
  47. https://supabase.com/docs/guides/auth/auth-mfa
  48. https://status.supabase.com/uptime
  49. https://supabase.com/sla
  50. https://github.com/supabase/auth
  51. https://www.g2.com/products/supabase-supabase/reviews
  52. https://guptadeepak.com/ciam-compass/vendors/supabase-auth/
  53. https://supabase.com/blog/client-libraries-v2
  54. https://www.okta.com/pricing/auth0/
  55. https://auth0.com/fine-grained-authorization
  56. https://frontegg.com/pricing
  57. https://frontegg.com/ciam
  58. https://developers.frontegg.com/ciam/sdks/overview
  59. https://developers.frontegg.com/ciam/api/overview
  60. https://status.frontegg.com/
  61. https://www.g2.com/products/frontegg/reviews
  62. https://www.capterra.com/p/206131/Frontegg/reviews/
  63. https://github.com/frontegg
  64. https://www.crunchbase.com/organization/frontegg