| — | Keycloakself-hosted IdP | Full IAM server: OIDC/SAML, user federation, strong auth, fine-grained authz. 36.4k stars, Java, server distribution (not a library). | observedtop10 | Source ↗ |
| — | ZITADELself-hosted IdP | Identity infrastructure with SSO, MFA, passkeys, OIDC, SAML, SCIM and first-class multi-tenancy. 14.9k stars, Go. | observedregister | Source ↗ |
| — | Ory Kratosself-hosted IdP | Headless, API-first identity and user management in Go; no UI of its own, so the host owns all identity screens. 13.8k stars. | observedtop10 | Source ↗ |
| — | authentikself-hosted IdP | Self-hosted IdP for SSO across SAML, OAuth2/OIDC, LDAP and RADIUS. 25.2k stars, mixed Python/Go/TS. | observedregister | Source ↗ |
| — | Ory Hydraself-hosted IdP | OpenID-certified OAuth2/OIDC server that delegates user management to an external IdP. 17.5k stars, Go. | observedregister | Source ↗ |
| — | Ory Ketoauthorization engine | Zanzibar-model permission server with relation tuples, ACL/RBAC/ReBAC and the Ory Permission Language. 5.4k stars, Go. | observedregister | Source ↗ |
| — | Autheliaself-hosted IdP | SSO and MFA portal designed as a forward-auth companion to reverse proxies (nginx, Traefik, Caddy, Envoy), now also OpenID-certified. 28.7k stars, Go. | observedregister | Source ↗ |
| — | Casdoorself-hosted IdP | Self-hosted IAM with an explicit multi-tenancy model: independent organizations each owning users, applications, providers and branding. 14.3k stars, Go + React. | observedregister | Source ↗ |
| — | Better Authauth library | Framework-agnostic TypeScript auth framework with a plugin ecosystem covering 2FA, SSO and multi-tenancy. 29.7k stars. Auth.js has joined Better Auth and now points new projects here. | observedtop10 | Source ↗ |
| — | Auth.js (NextAuth.js)auth library | Web-standards auth for Next.js, Nuxt, SvelteKit, SolidJS and Remix; works with or without a database. 28.3k stars, TypeScript. | observedregister | Source ↗ |
| — | Luciaauth library | README states verbatim that Lucia was deprecated on March 2025; repositioned as a learning resource pointing at a single-file session implementation plus the maintainer's Auth Book. 10.5k stars. | observedrejected | Source ↗ |
| — | Open Policy Agentauthorization engine | CNCF-graduated (Feb 2021) general-purpose policy engine. Embeddable as a Go library, runnable as a sidecar/daemon, or compiled to WASM. 12.2k stars. | observedtop10 | Source ↗ |
| — | Cerbosauthorization engine | Stateless authorization PDP with YAML policy files; deploys as a Kubernetes service, sidecar, systemd unit or Lambda. 4.6k stars, Go. | observedregister | Source ↗ |
| — | SpiceDBauthorization engine | Most mature OSS Zanzibar implementation; adds caveated relationships combining ABAC with ReBAC. 7.0k stars, Go. Explicitly verified NOT BSL/source-available. | observedtop10 | Source ↗ |
| — | OpenFGAauthorization engine | CNCF project (community Slack under cncf), Zanzibar-inspired, in production behind Auth0 FGA since Dec 2021. Embeddable as a Go library or run as a service. 5.7k stars. | observedregister | Source ↗ |
| — | Casbinauthorization engine | Embedded authorization library (not a server) built on the PERM metamodel — Policy, Effect, Request, Matchers — so swapping ACL/RBAC/ABAC is a config change, not a code change. Includes RBAC with domains/tenants. 20.4k stars. | observedregister | Source ↗ |
| — | single-spamicrofrontend shell | Top-level router for microfrontends. Apps register via registerApplication(name, loadFn, activeWhen) and export bootstrap/mount/unmount lifecycle promises; the router mounts and unmounts on route change. 13.9k stars. | observedtop10 | Source ↗ |
| — | Module Federation 2.0microfrontend shell | Runtime code-sharing across JS applications. 2.0 adds a standalone Federation Runtime, a runtime plugin system, a Manifest describing federated modules, dynamic TypeScript type hinting and a Chrome devtool. Webpack and Rspack. 2.6k stars. | observedtop10 | Source ↗ |
| — | Piralmicrofrontend shell | App-shell framework where 'pilets' are runtime-loaded modules that extend other pilets or expose extension slots, can be rolled out or disabled dynamically, and are transferrable between host applications. 1.9k stars, TypeScript. | observedregister | Source ↗ |
| — | qiankunmicrofrontend shell | Microfrontend solution with a Proxy-membrane JS sandbox isolating window/document/timers/listeners per app, opt-in CSS @scope style isolation, and native ESM support. @qiankunjs/sandbox is publishable standalone to contain any third-party script. 16.7k stars. | observedregister | Source ↗ |
| — | Luigi (SAP)microfrontend shell | SAP's micro-frontend framework for admin UIs, split into Luigi Core (host, owns routing/navigation/authorization config) and Luigi Client (embedded in each MF), communicating over postMessage. 923 stars. | observedregister | Source ↗ |
| — | FrintJSmicrofrontend shell | Modular reactive JS framework for scalable apps. 757 stars. | observedrejected | Source ↗ |
| — | Backstageportal/workspace shell | CNCF Incubation-level developer-portal framework from Spotify, 34.3k stars. Plugin-first: every feature including the catalog is a plugin. Plugins export routable extensions bound via route refs so they link to each other without hardcoded paths. | observedtop10 | Source ↗ |
| — | Appsmithportal/workspace shell | Platform for admin panels, internal tools and dashboards, integrating 25+ databases and any API. 40.8k stars. | observedregister | Source ↗ |
| — | ToolJetportal/workspace shell | Low-code platform for internal tools, dashboards, workflows and AI agents. 40.8k stars, JS/TS. | observedregister | Source ↗ |
| — | Budibaseportal/workspace shell | Low-code platform for internal apps, automations and agents. 28.2k stars, Svelte builder + Koa server. | observedrejected | Source ↗ |
| — | NocoBaseportal/workspace shell | Microkernel no-code platform where everything is a plugin. 23.9k stars. | observedrejected | Source ↗ |
| — | Frappe Frameworkportal/workspace shell | Low-code full-stack framework (Python/MariaDB server, integrated client library) underlying ERPNext, with a built-in admin interface, role-based permissions, auto-generated REST API and customizable forms/views. 10.6k stars. | observedregister | Source ↗ |
| — | GrowthBooksettings/flags | Feature flags with advanced targeting, gradual rollouts and experiments, warehouse-native, 24 SDKs plus REST API and webhooks. 8.2k stars. | observedregister | Source ↗ |
| — | Unleashsettings/flags | Open-source feature management platform. 13.8k stars, TypeScript/Node. | observedregister | Source ↗ |
| — | Flagsmithsettings/flags | Open-source feature flagging and remote config service. 6.5k stars, Django/Python API + React frontend. | observedtop10 | Source ↗ |
| — | SuperTokensself-hosted IdP | Self-hostable auth service positioned as an open-source alternative to Auth0/Firebase Auth/Cognito, with prebuilt and custom UI recipes for email-password, passwordless, social and session management. 15,285 stars, Java core. | observedregister | Source ↗ |
| — | Logtoself-hosted IdP | Auth infrastructure for SaaS and AI apps built on OIDC and OAuth 2.1, with first-class multi-tenancy, prebuilt sign-in experience and a management API. 14,469 stars, TypeScript. | observedtop10 | Source ↗ |
| — | oauth2-proxyauth library | Reverse proxy that terminates authentication in front of an upstream app against Google, Azure, GitHub, generic OIDC and many other providers, injecting identity headers downstream. 14,878 stars, Go. | observedregister | Source ↗ |
| — | jose (panva)auth library | Zero-dependency implementation of JWA, JWS, JWE, JWT, JWK and JWKS running on Node.js, browsers, Cloudflare Workers, Deno and Bun. 7,768 stars, TypeScript. | observedregister | Source ↗ |