6 free alternatives to Firebase Authentication

Auth0's free plan gives you up to 25,000 monthly active users, plus passwordless authentication, unlimited social connections subject to system limits, 5 organizations, 1 enterprise connection, self-service SSO, SCIM, basic attack protection, brand customization, and a custom domain. That makes it a broad auth starter kit for apps that need hosted login, organization support, and some enterprise-style features without paying first. It is still free-tier limited, but the shape of the package is more identity-platform oriented than Firebase's phone and MAU-centric allowance. Builders who want a polished hosted login experience with more org and enterprise controls should consider it.

• Beats Firebase Authentication: Broader built-in enterprise identity features like organizations, SCIM, and self-service SSO.
• Falls short: Lower free MAU ceiling than Firebase Authentication's Identity Platform allowance, and a card is required for the custom domain.
• Who should switch: Switch to Auth0 if you need more enterprise identity workflows than Firebase's free tier gives you.

See the full listing · Compare with Firebase Authentication

Logto's free plan includes up to 50,000 monthly active users, 50,000 tokens per month, user authentication, 1 machine-to-machine app, account APIs, audit logs and user management, 3 total applications, 3 social connectors, 1 custom domain, 1 webhook, 3-day audit log retention, and 1 tenant member for console access. It is a good fit for teams that want an auth service with explicit developer and SaaS primitives, especially if tokens, apps, and webhooks matter in the same place as login. The free tier stays permanently available and does not require a credit card. Builders with API-heavy auth needs should look closely.

• Beats Firebase Authentication: Clearer free allowances for tokens, apps, webhooks, and audit logs.
• Falls short: Its free MAU ceiling is similar to Firebase Authentication's Identity Platform cap, not higher.
• Who should switch: Switch to Logto if you want a more developer-centric auth stack with token and webhook limits spelled out.

See the full listing

Amazon Cognito's free tier covers up to 10,000 monthly active users per month for direct sign-ins or social identity providers on Lite or Essentials tiers, up to 50 monthly active users for SAML 2.0 or OIDC federated sign-ins, and free identity-pool authentication with unique identifier generation. The free tier is indefinite for new and existing AWS customers, and there is no 12-month expiration. It also supports branded sign-in and federation across human and machine identities, though the free tier does not extend to every tier or every use case. If you are already in AWS and want identity-pool features in the same ecosystem, it is a natural option.

• Beats Firebase Authentication: Free identity-pool authentication and indefinite availability with no 12-month expiration.
• Falls short: Lower direct/social MAU ceiling than Firebase Authentication's Identity Platform allowance.
• Who should switch: Switch to Amazon Cognito if your app already runs on AWS and identity pools matter more than a larger free MAU cap.

See the full listing

Clerk's free tier includes up to 3 dashboard seats, unlimited applications, 50,000 monthly retained users per app, up to 5 user impersonations, APIs and prebuilt UIs for sign-up, sign-in, and user profile, custom domain support, a fixed 7-day session lifetime, machine authentication with API keys and M2M tokens subject to monthly limits, up to 3 social connections, usernames, password checks, email code and email link auth, webhooks, account protection, custom session tokens, custom JWT templates, data exports, B2B and administration add-ons with included caps, and organization support. It is a good fit for teams that want a lot of ready-made auth UI and admin features without paying upfront. The free tier does not require a card.

• Beats Firebase Authentication: More out-of-the-box auth UI, account management, and organization features in the free tier.
• Falls short: Lower MAU-style capacity than Firebase Authentication's Identity Platform cap.
• Who should switch: Switch to Clerk if you want a richer prebuilt auth and admin layer for a small app.

See the full listing

SuperTokens' free tier includes email/password authentication, social login and SSO providers, passwordless magic-link auth, SMS and email OTP, username/password auth, phone number and password auth, email verification and forgot-password flows, sign-up and sign-in page UI, RBAC, a user management dashboard, session management, overrides for hooks and custom actions, SOC 2 compliance, community support, and free use under 5,000 monthly active users on the cloud plan. It stands out because the self-hosted offering is open source and has no MAU count limit, while the managed cloud stays free below the stated cap. If you want to own the stack or avoid a cloud MAU ceiling, it is a strong fit.

• Beats Firebase Authentication: Self-hosted option with no MAU count limit on the open-source path.
• Falls short: The managed cloud free tier caps at 5,000 MAU, well below Firebase Authentication's Identity Platform allowance.
• Who should switch: Switch to SuperTokens if you want open-source control or expect to self-host later.

See the full listing

Kinde's free tier includes 10,500 monthly active users, 5 monthly active organizations, unlimited dashboard seats, unlimited applications, billing and portal features, 1 billing webhook, billing APIs, hosted auth flows, email and password login, passwordless email, 10 SMS for passwordless phone auth, username auth, social sign-on, SAML and Enterprise SSO, device flow auth, 2,000 M2M tokens, API authorization, custom claims, MFA options, custom session tokens, custom JWT claims, custom domain, feature flags, and broad security controls. It also includes customer self-serve billing and subscription tooling, which is unusual for an identity product. The free tier is perpetual and does not require a card, though transaction fees apply. Teams building SaaS with auth plus billing in one place should pay attention.

• Beats Firebase Authentication: Auth plus billing, feature flags, and SaaS workflow tooling in one free package.
• Falls short: Much lower MAU ceiling than Firebase Authentication's Identity Platform allowance.
• Who should switch: Switch to Kinde if you want identity and billing together instead of a standalone auth service.

See the full listing