A lighter open source Keycloak alternative for AI agents
theAuthvsKeycloak
Keycloak is an Apache 2.0 identity server you deploy and operate for SSO across many apps. theAuth is a library embedded in your app, built around AI agent identity.
Last verified: 2026-10-07. Identity server against an MIT library.
You want a central identity provider that many applications and teams sign in through.
You need user federation to LDAP or Active Directory and identity brokering to existing providers.
You have a team comfortable running a Java service and want a CNCF incubation project behind it.
Choose theAuth if
You want auth inside your application process, not a separate Java server to deploy and patch.
Agents need their own identity with delegation limits, budgets and a per-agent audit trail.
You target Workers, Deno or Bun, or you want Go and Python SDKs.
theAuth is an open source Keycloak alternative for teams that want agent identity in the same library as human sign-in. It is not the right pick for every team, and the first column says so.
theAuth vs Keycloak feature comparison
Feature comparison of Keycloak and theAuth
Feature
Keycloak
theAuth
Source license
Yes, Apache 2.0
Yes, MIT
Deployment
Standalone server (Java, Quarkus)
Library in your app; Go module via go get
Self-hostable
Yes, Yes, you run it
Yes, Yes, on your own database
SAML 2.0 and OIDC
Yes, Yes, plus OAuth 2.0
Yes, SAML 2.0 and OIDC SSO, SCIM 2.0
LDAP and Active Directory federation
Yes, User federation to LDAP or Active Directory
Partial or different, Not in theAuth's documented feature list
Identity brokering
Yes, Brokers to OIDC or SAML identity providers
Partial or different, 17 OAuth providers plus a generic OIDC factory
OAuth 2.1 authorization server for MCP
Yes, Used as the example server in the MCP authorization tutorial
Yes, Yes, built in
Agent identity
Partial or different, Not found in the docs we checked; client service accounts exist
Yes, Owner, delegation, budgets, audit
Fine-grained authorization
Yes, Role-based and policy-based
Yes, RBAC, ReBAC and a policy engine
Check mark: yes. Dash: partial, different, or not found in the docs we checked. Cross: no. Claims about Keycloak are from its own public docs (see Sources); theAuth rows are from its repositories.
01
Keycloak alternative for AI agents: identity and delegation
A general IdP, or an agent-aware library.
Keycloak
Keycloak is a general identity and access management server. Its admin guide documents OIDC clients, service accounts and client policies. We did not find an agent identity model with delegation chains or per-agent budgets in the docs we checked, so you would build that on top.
theAuth
theAuth models an agent as an identity with an owner, a cryptographic bearer token (kv_...), wildcard permissions such as mcp:github:*, and delegation chains with configurable depth limits. On top of that sit budget policies per agent, trust scoring, CIBA-style approval for sensitive tool calls, and a full audit trail of every agent action. Read the agents guide and delegation docs.
02
MCP OAuth 2.1 support
Keycloak works as an MCP authorization server.
Keycloak
The official MCP authorization tutorial uses Keycloak as its example authorization server. It says the default configuration already supports capabilities MCP needs, including dynamic client registration, though default policies restrict anonymous registration, so you set trusted hosts. The Keycloak admin guide also has an OAuth 2.1 compliance section.
theAuth
theAuth ships an OAuth 2.1 authorization server for MCP: PKCE S256, RFC 9728 protected resource metadata, RFC 8707 resource indicators, RFC 8414 server metadata and RFC 7591 dynamic client registration. The Go module adds RFC 8693 token exchange, DPoP, PAR, JAR, CIBA, CIMD per the MCP spec of 2025-11-25 and refresh token rotation with family revocation. See the MCP guide.
03
Self-hosted Keycloak alternative: data ownership
A server you run, or a library you embed.
Keycloak
Keycloak is open source and you operate it: a standalone Java server on Quarkus, clustered for availability, with its own admin and account consoles. That gives you ownership and a lot to run. theAuth stores data in your application's database and needs no separate identity server.
theAuth
theAuth is MIT licensed and runs against your own database: SQLite, PostgreSQL, MySQL or Cloudflare D1 in TypeScript, and Postgres, MySQL or in-memory storage in Go. Users, sessions, tokens and audit records stay in storage you control. A hosted theAuth Cloud is in early access for teams that would rather not run it.
04
Licensing and cost model
Apache 2.0 and MIT, both free to run.
Keycloak
Keycloak is Apache 2.0 licensed and free to use, with no vendor pricing page to read. The cost is operating the server: hosting, upgrades, patching and the people who know Keycloak. theAuth's cost is similar in kind but smaller in footprint because it runs in your app.
theAuth
The library is free under the MIT license. Your costs are the database, the compute and the engineering time to operate it. theAuth Cloud is in early access and has no published prices.
05
Edge runtimes
Where each one runs.
Keycloak
Keycloak is a Java server, so edge runtimes are not where it runs. Your edge app would call it over OIDC and verify its tokens. theAuth's TypeScript core can run on the edge itself.
theAuth
The TypeScript core runs on Cloudflare Workers, Deno and Bun without code changes, with three runtime dependencies: drizzle-orm, jose and zod. Adapters cover Next.js, SvelteKit, Nuxt, Hono, Express, Fastify, Astro, NestJS, SolidStart and TanStack Start.
Migrating from Keycloak to theAuth
There is no Keycloak-specific theAuth migration guide yet. Start from the migration hub. If you use LDAP or Active Directory federation, plan around it, because theAuth does not list that capability.
It can be for application-level auth. theAuth is an MIT library embedded in your app, with agent identity, delegation limits, budgets, audit and an MCP OAuth 2.1 authorization server. Keycloak remains stronger as a central identity provider with LDAP and Active Directory federation.
Is Keycloak open source?
Yes. Keycloak is licensed under Apache 2.0 and is a CNCF incubation project. theAuth is MIT licensed.
Can Keycloak secure an MCP server?
Yes. The official MCP authorization tutorial uses Keycloak as the example authorization server and notes its default configuration supports dynamic client registration, with policies that restrict anonymous registration.
Do I need a separate server for theAuth?
No. In TypeScript, theAuth runs inside your application with a database you choose, and in Go it is a single go get. Keycloak is a standalone server you deploy and operate.
When should I choose Keycloak over theAuth?
Choose Keycloak when you need one identity provider for many applications, LDAP or Active Directory federation, or identity brokering, and you have a team to operate a Java service.
Sources
Last verified: 2026-10-07. Competitor facts come from the public pages below; plans and prices change, so confirm there.
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.