Back to catalog
Tesseral
MITTesseral is an open-source B2B auth engine replacing WorkOS and Auth0 with self-hostable SAML SSO, SCIM directory sync, and native multi-tenancy.
Open-source alternative to — compare it against:
Overview
Tesseral is an open-source authentication engine designed specifically for multi-tenant business software. Rather than treating users as isolated individual accounts, it structures organizations, role hierarchies, and enterprise single sign-on as native architectural primitives. Applications integrate via backend SDKs and prebuilt customer-facing portals that run either in Tesseral's managed cloud or self-hosted in your own environment.
Why Tesseral instead of WorkOS
WorkOS provides developer APIs and an administrative portal to bridge business applications with enterprise identity providers. However, relying on WorkOS ties your authentication pipeline to a proprietary cloud service with escalating pricing tiers for SAML connections and directory integrations. Migrating away from a closed vendor often requires rewriting webhook consumers and restructuring user session models that are tightly coupled to external endpoints.
Through an integrations lens, Tesseral changes where authentication logic runs. It provides client and server SDKs across Go, Rust, Python, and Node.js that validate access tokens locally in your application middleware, keeping latency low and avoiding outbound API calls on every request. Tenant membership, role-based access control checks, and SCIM directory events connect straight to your application data layer. Teams can run the entire engine alongside their own PostgreSQL instances, maintaining sovereignty over identity records while avoiding the per-connection enterprise surcharges common to proprietary identity platforms like WorkOS and Auth0.
What it does well
- Structured multi-tenancy: organizes accounts into distinct customer organizations where client administrators invite members and configure tenant-level security policies.
- Enterprise protocol support: handles SAML 2.0 and OpenID Connect single sign-on alongside SCIM provisioning for automated employee syncing across identity providers.
- Local middleware verification: verifies cryptographic access tokens in Go, Python, Rust, and Node.js backend services without making synchronous HTTP calls back to a central auth server.
- Customer-facing management portals: delivers prebuilt, embeddable settings pages where enterprise customers manage their own single sign-on credentials and review active sessions.
- Multi-factor authentication options: supports hardware passkeys via WebAuthn, time-based one-time password applications, email magic links, and managed API keys for programmatic service calls.
