Open source alternatives to paid SaaS apps: Notion, Slack, Auth0, Vercel and more. Curated list with licenses and GitHub stars.
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Updated
Oct 14, 2026 - JavaScript
Open source alternatives to paid SaaS apps: Notion, Slack, Auth0, Vercel and more. Curated list with licenses and GitHub stars.
Open-source Identity and Access Management Server (Keycloak alternative)
Self-hosted, open-source alternative to Auth0, built on Better Auth: OIDC provider, passkeys, SSO, organizations and an admin console.
Self-hosted, multi-tenant OpenID Connect and SAML identity server in Rust: OAuth 2.0, MFA and passkeys, LDAP and Kerberos, SCIM 2.0, admin and account consoles, optional FIPS 140-3 build. One container, Postgres and Valkey. MIT.
Official SDKs for Authon — authentication platform for modern apps
Ultra-lightweight, API-first Identity & Access Management (IAM) platform built in Rust — a self-hosted, open-source alternative to Auth0/Okta/Keycloak with OIDC, GraphQL admin API, and a modern React dashboard.
Open-source Auth-as-a-Service on Cloudflare Workers. Password login, OIDC SSO, JWT + refresh tokens, user ban/moderation — deploy in 5 minutes. Free Auth0/Clerk alternative.
🔑 Passwordless WebAuthn/Passkey authentication SDK. Zero cost. Replaces Auth0 & Okta.
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