Alternatives, with sources
Compare theAuth with Auth0, Clerk, Better Auth and more
Looking for an open source or self-hosted alternative for AI agents? Each page below says what the other tool does well, where theAuth differs, and links to the sources we checked.
When to pick what
Three honest options. Only the last one is theAuth.
- A hosted vendor
- Auth0, Clerk or Firebase Authentication fit when you want someone else to run login, polished UI and support, and your data can live with the vendor. You trade control and a usage-based bill for speed.
- An open source library or server
- Better Auth, Supabase Auth or Keycloak fit when you want to run it yourself. Better Auth suits TypeScript apps, Supabase Auth suits teams on Supabase Postgres, and Keycloak suits a central identity provider with LDAP.
- theAuth
- It fits when AI agents are part of the system and you want each one to have an owner, scoped permissions, delegation limits, budgets and an audit trail, in the same MIT library as human sign-in, with an MCP OAuth 2.1 authorization server.
Overview across six tools
Only rows we could verify from each tool's public docs. Open a comparison for the detail and sources.
| Feature | Auth0 | Clerk | Better Auth | Supabase | Firebase | Keycloak | theAuth |
|---|---|---|---|---|---|---|---|
| Delivery model | Hosted platform | Hosted platform | Open source library | Backend platform | Managed service | Identity server | Library you run; Cloud in early access |
| Source license | No, Proprietary | No, Proprietary | Yes, MIT | Yes, MIT | Managed service | Yes, Apache 2.0 | Yes, MIT |
| Self-hostable | Partial or different, Managed private cloud only | No, No | Yes, Yes | Yes, Yes | No, No | Yes, Yes | Yes, Yes |
| OAuth 2.1 server for MCP | Yes, Yes | Yes, Yes | Yes, Yes | Yes, Yes | Partial or different, Not documented | Yes, Yes | Yes, Yes |
| Agent identity as its own model | Partial or different, Add-on: Token Vault, CIBA | Partial or different, Not found | Partial or different, Plugin, not yet stable | Partial or different, Agents act as users | Partial or different, Not documented | Partial or different, Not found | Yes, Yes, core |
| Enterprise SSO | Yes, Yes | Yes, Yes | Yes, Plugin | Yes, SAML 2.0 | Partial or different, Identity Platform upgrade | Yes, Yes | Yes, SAML 2.0, OIDC, SCIM |
Check mark: yes. Dash: partial, different, or not found in the docs we checked. Cross: no. Last verified: 2026-10-07.
Pick a comparison
- theAuthvsAuth0Auth0 is the hosted platform with Universal Login and enterprise connections. theAuth is the MIT library you run yourself.Read the comparison
- theAuthvsClerkClerk is hosted auth with polished drop-in components. theAuth is an MIT library you run, with agents as identities.Read the comparison
- theAuthvsBetter AuthBoth are MIT libraries. Better Auth has the larger community and plugin set; theAuth builds agent identity into the core.Read the comparison
- theAuthvsSupabase AuthSupabase Auth is one part of a Postgres platform with Row Level Security. theAuth is auth alone, with agents as identities.Read the comparison
- theAuthvsFirebase AuthFirebase Authentication is Google's managed sign-in for mobile and web. theAuth is a self-hosted MIT library for agents and humans.Read the comparison
- theAuthvsKeycloakKeycloak is an Apache 2.0 identity server for SSO across many apps. theAuth is a library embedded in your app.Read the comparison
Choosing an auth tool: common questions
Which auth tool is the best alternative for AI agents?
It depends on where you want to run it. Several tools now offer an OAuth 2.1 authorization server for MCP, so the difference is how agents are modeled. theAuth gives each agent its own identity with an owner, delegation limits, budgets and an audit trail, in an MIT library you run yourself.
Is theAuth better than Auth0 or Clerk?
Not for every team. Auth0 and Clerk are hosted products with polished login experiences, and that is the right choice if you want a vendor to run auth. theAuth fits when you want to self-host, own your data, and model agents as identities.
Should I use a library or a hosted vendor for auth?
Use a hosted vendor when speed and not operating anything matter most. Use a library when you need your data in your own database, want the code in your repository, or have requirements a vendor does not cover.
Migration guides Agent identity MCP OAuth 2.1 Docs comparisons
Get started
Give your first agent an identity.
Install the package, create an agent with scoped permissions, and read its first audit record. The core runs on Postgres, SQLite, MySQL or D1, and the Go module needs a single go get.
npm install @glinr/theauthgo get github.com/glincker/theauth-go