Compare

FoxAuth compared with Auth0

Auth0 is a managed identity service billed per monthly active user. FoxAuth is a server you run, with every protocol feature included.

Last checked 2026-09-03 against the linked sources. Auth0 changes; where its documentation did not say, this page says so rather than guessing. Found something out of date? Tell us at hello@foxauth.dev.

The short answer

Pick Auth0 if you want identity as a service this week, with social connections and certified FAPI you can hand to a reviewer. Pick FoxAuth if the data must live in your own database, your per-user bill is the problem, or you need the banking-grade profiles without an Enterprise add-on.

Choose Auth0 if…

You do not want to run a database or a container, ever.
You need social and enterprise connections working this week.
You want certified FAPI conformance and a support organisation with a status page.
Your identity budget is smaller than the cost of an engineer keeping a server healthy.

Choose FoxAuth if…

Your cost grows with your user count and you would rather it grew with your infrastructure.
A regulator or a contract requires identity data to stay in your own database.
You need DPoP, PAR, CIBA or mTLS without an Enterprise plan and an add-on.
You want an AI agent administering the instance through the same audited path a human uses.

Side by side

Every row has a verdict and the reason for it

●: Built in
◐: Behind a flag, preview or add-on
○: Not available
?: Not documented
—: Not applicable

Row verdicts: 6 FoxAuth ·4Auth0 · 3 even ·4 different goals. A count is not a recommendation — the rows that matter to you are the ones that count.

Dimension	FoxAuth	Auth0	Verdict
Getting started and operations
Hosting model	●Self-hosted container, or imported as a library.	●Managed multi-tenant cloud, or Private Cloud on AWS or Azure. Self-hosting is not documented.	Different goals Run it yourself, or have it run for you. Every other row follows from this one. What their docs say Private Cloud is described as "A dedicated, managed cloud service".
Runtime and code	●TypeScript on Bun. The whole server is code you can read and fork.	—Auth0's runtime. Customisation is through Actions, not the server.	Different goals One is software you own; the other is a service you configure.
Where the data lives	●Your own MongoDB.	○Auth0's store. Customer-operated storage is not documented.	FoxAuth Identity data stays in a database you control.
Social and enterprise connections	◐Upstream OIDC federation per user bucket, behind federation.enabled.	●A catalogue of social and enterprise connections out of the box.	Auth0 Auth0's connection catalogue is far broader.
Operations burden	◐You run a database and a container, and you apply upgrades.	●None. Uptime, upgrades and scaling are Auth0's.	Auth0 If you cannot operate a database, choose the managed service.
Maturity	◐0.1.0, the first tagged release (September 2026).	●Established product, support organisation, status page, years of certifications.	Auth0 The honest asymmetry.
Protocol coverage
PKCE for every client (OAuth 2.1)	●Mandatory for every client. Exact redirect matching; no Implicit or password grant.	◐Documented for public clients. A requirement for every client is not documented.	FoxAuth OAuth 2.1 behaviour is the default. What their docs say PKCE is documented for "applications that cannot store a client secret, such as native or single-page apps".
DPoP (RFC 9449)	◐Including server nonces, behind dpop.enabled.	◐Supported, enabled per resource server; a nonce is required.	Even Both implement it with nonces. What their docs say "Auth0 supports mTLS sender constraining and Demonstrating Proof-of-Possession (DPoP)" and "requires your DPoP HTTP header to have a nonce value".
Pushed Authorization Requests (RFC 9126)	◐Behind par.enabled, in every install.	◐Enterprise Plan with the Highly Regulated Identity add-on.	FoxAuth Included, not an Enterprise add-on. What their docs say "you must have an Enterprise Plan with the Highly Regulated Identity add-on".
FAPI profiles	◐Profile behaviours behind fapi.enabled. No conformance certification.	●Certified FAPI provider; FAPI 1 Advanced compliance on the Enterprise Plan with the add-on.	Auth0 A certification you can hand to a reviewer. What their docs say "Auth0 is a certified FAPI provider."
CIBA	◐Behind ciba.enabled, in every install.	◐Enterprise Plan or an add-on; email notifications need a paid add-on.	FoxAuth Included in every install.
mTLS (RFC 8705)	◐Client authentication and certificate-bound tokens, behind mTLS.enabled.	◐Enterprise Plan with the Highly Regulated Identity add-on.	FoxAuth Included, not an Enterprise add-on.
Dynamic client registration	◐RFC 7591 and RFC 7592 management, each behind its own flag, any grant type.	◐Disabled for all tenants by default; third-party clients only, authorization_code and refresh_token only, rate-limited.	FoxAuth Full RFC 7591 and 7592 without the restrictions.
Administration and agents
Admin console and API	●Built-in console and the same management API behind it.	●The Dashboard, and a Management API that covers everything the Dashboard does.	Even Both give you a UI and an API for the same operations. What their docs say "anything that can be done through the Auth0 Dashboard can also be done through this API".
Administration by an AI agent (MCP)	◐The server itself is the MCP resource: 60 tools, the console's own checks and audit trail, two-call confirmation. Behind mcp.enabled.	●A separate Auth0 MCP Server that calls the Management API, authenticated with the Device Authorization flow.	Even Both exist. Ours runs inside the server through the console's code path; theirs is a separate component in front of the API. What their docs say The Auth0 MCP Server "connects AI agents to your Auth0 tenant".
Licence and cost
Licence	●FSL-1.1-ALv2, source-available; each release becomes Apache 2.0 after two years.	—A proprietary service; no source licence applies.	Different goals Source you can read and fork, versus a service agreement.
Pricing model	●Free to self-host, every feature included. Support by agreement.	◐Free up to 25,000 monthly active users, then per-MAU plans; regulated-industry features need Enterprise and an add-on.	Different goals A fixed infrastructure cost versus a bill that grows with your users. What their docs say Plans are "priced by Monthly Active Users (MAUs) and differ between B2C and B2B"; the free plan covers "Up to 25,000 monthly active users".

Migrating

Auth0 can export users and clients, and its Management API can list both. FoxAuth clients are then created through the admin API or dynamic registration, and users through a user bucket. Password hashes are not portable, so plan a reset-on-first-login window.

Sources

What we read

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