Auth0 is a hosted identity platform you call as a service. theAuth is an MIT library you run next to your own data, with AI agents modeled as identities of their own.
Last verified: 2026-10-07. Hosted platform against an MIT library.
You want a vendor to run login, with a hosted Universal Login page you customize from a dashboard.
You need enterprise SSO connections and a support relationship with a large hosted vendor.
You want Auth0 for AI Agents (Token Vault for third-party API tokens, asynchronous authorization) without operating anything.
Choose theAuth if
Your agents need their own identity: an owner, scoped permissions, delegation depth limits, budgets and a per-agent audit trail, in the same library as human sign-in.
You need to self-host, or keep tokens, sessions and audit data in your own database.
You want auth code in your repository under MIT, running on Workers, Deno or Bun.
theAuth is an open source Auth0 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 Auth0 feature comparison
Feature comparison of Auth0 and theAuth
Feature
Auth0
theAuth
Source license
No, Proprietary (per theAuth README)
Yes, MIT
Self-hostable
Partial or different, Managed private cloud on AWS or Azure for teams that cannot use the public cloud; not self-hosted
Yes, Yes, on your own database
OAuth 2.1 authorization server for MCP
Yes, Yes, Auth0 for MCP
Yes, Yes, built in
Dynamic client registration
Partial or different, Supported; Auth0 recommends manual CIMD registration for production and lists open DCR security controls as Enterprise only
Yes, RFC 7591 supported; CIMD in the Go module
Agent-specific features
Partial or different, Auth0 for AI Agents: Token Vault and CIBA, sold as an add-on on paid plans
Yes, Universal Login, customizable in the dashboard
Partial or different, Headless building blocks and client SDKs, no hosted page
Enterprise SSO
Yes, Enterprise connections; included counts vary by plan
Yes, SAML 2.0 and OIDC SSO, SCIM 2.0
Entry cost
Yes, A free plan exists; see the pricing page for limits
Yes, MIT library; Cloud in early access, no published prices
Check mark: yes. Dash: partial, different, or not found in the docs we checked. Cross: no. Claims about Auth0 are from its own public docs (see Sources); theAuth rows are from its repositories.
01
Auth0 alternative for AI agents: identity and delegation
Both cover agents acting for users. They model them differently.
Auth0
Auth0 for AI Agents is an add-on to paid plans. Its Token Vault manages issuance, storage, rotation and revocation of tokens for external APIs such as Google, Microsoft, Jira and Notion, and it supports asynchronous authorization (CIBA). The focus is an agent acting on behalf of a signed-in user with centralized authorization.
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
Auth0 can be your MCP authorization server too.
Auth0
Auth0 documents Auth for MCP: it acts as the authorization server, issues tokens, exposes discovery metadata, and lets an MCP server exchange a client token for a short-lived token scoped to an internal API. For production it recommends manual CIMD registration over open dynamic client registration, and says the security options for open registration are for Enterprise customers.
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 Auth0 alternative: data ownership
Hosted by Auth0, or stored in your database.
Auth0
Auth0 runs the service. For organizations that cannot use the multi-tenant public cloud it offers managed private cloud on AWS or Azure. In both cases Auth0 operates it; you do not run the code yourself.
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
Proprietary plans against an MIT library.
Auth0
Auth0 is proprietary and sold by plan, with limits that change by plan: monthly active users, organizations, enterprise connections, machine-to-machine tokens and the AI agents add-on. Prices and limits move, so read the Auth0 pricing page instead of trusting a number copied here.
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.
Auth0
Auth0 is a hosted service your app reaches over HTTPS, so any runtime that can make requests and verify JWTs can use it. How much SDK support you get on a given edge platform varies, so check the SDK for your runtime.
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 Auth0 to theAuth
theAuth has an Auth0 migration guide. It maps tenants, applications, machine-to-machine clients, Actions and organizations to theAuth equivalents, with code diffs, a user export and import plan, and a rollback plan. Plan for what you give up: Auth0's hosted Universal Login page and Guardian MFA app have no direct equivalent, because theAuth ships headless building blocks. The repository also has a migrate-from-auth0 example.
It can be. theAuth is an open source library that gives each AI agent its own identity, scoped permissions, delegation limits and audit trail, and it includes an MCP OAuth 2.1 authorization server. Auth0 also offers Auth0 for AI Agents and Auth for MCP as a hosted service, so the real choice is how you want to run it and how you want to model agents.
Can I self-host Auth0?
No. Auth0 offers managed private cloud on AWS or Azure for organizations that cannot use the multi-tenant public cloud, but Auth0 operates it. theAuth is MIT licensed and runs on your own database.
Does Auth0 support MCP OAuth 2.1?
Yes. Auth0 documents Auth for MCP, where it acts as the authorization server for an MCP server. It recommends manual CIMD registration over open dynamic client registration in production. theAuth also ships an MCP OAuth 2.1 authorization server, built into the library.
What do I lose when I move from Auth0 to theAuth?
Mainly the hosted pieces. Universal Login is a hosted page that Auth0 runs and you customize in a dashboard, and theAuth provides headless building blocks instead. You also give up having a vendor operate the service.
How does Auth0 pricing compare with theAuth?
Auth0 sells plans with limits on monthly active users, organizations, connections and add-ons, and those numbers change, so check its pricing page. The theAuth library is free under MIT, and you pay for your own database and compute. theAuth Cloud is in early access with no published prices.
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.