Free alternative

Free alternative to Auth0

Auth0 costs €30 a month. Casdoor does the same job for free, in open source: you install it on your machine or a small server, and you stop paying.

Public entry price, taken from Auth0’s website (auth0.com). Over a year, that is €360 that stays in your pocket.

What replaces Auth0

The main alternative

Casdoor

🔴 Advanced⏱️ ~40 min to installSave €30/mo

Casdoor is a complete identity server you host yourself: it keeps your users' accounts, shows the login page and manages access to all your apps. More than 14,000 stars on GitHub, an Apache 2.0 licence, several releases a week, and an interface that speaks French. Your users sign in with a password, an email or SMS code, a passkey or face recognition, or with more than 100 providers such as Google, GitHub or Microsoft, with two factor authentication as an option. It speaks every protocol: OAuth 2.0, OpenID Connect, SAML, CAS, LDAP and SCIM, so a recent app and an old enterprise tool can share the same accounts. Everything is set in the console: organisations, applications, sign in methods, email templates, logo and colours of the login page. Access rights rely on Casbin (roles and fine grained rules), and an MCP server lets Claude manage your users in plain language. Technically it is a single Go program plus a database, with no Java and no cluster. If you would rather not host it, a hosted version exists on casdoor.com, free up to 25,000 monthly active users. The point to know before installing it: Casdoor has published 18 security flaws since early 2025, 8 of them critical in 2026, the last two in mid September, all fixed since. Its open source competitors published some this year too, but an identity server gets updated every week, no exceptions. And the default administrator password, admin and 123, gets changed at the very first login.

Loucash’s verdict on Casdoor

6/10

Casdoor does what Auth0 does, for free: a login page in your colours, sign in with Google, two factor authentication, enterprise SSO, permission management. And it does it on your server, with no bill that grows with your users. What I like: everything is set in the console, in French, and the MCP server lets Claude manage accounts for me. Why 6 and not more: it is an identity server, and its security record means I have to warn you. Eight critical flaws published in 2026, the last two in mid September, all fixed since, but it means you must update it every week, no exceptions. The interface is dense, and you need to understand OpenID Connect to connect your app. If you are a beginner and stay under 25,000 monthly active users, Auth0's free plan is the safer choice for you.

Who it is for: You run several apps or have clients who want their accounts with you, you know how to update a server every week, and Auth0 is starting to cost you. If you are a beginner, or you fit in Auth0's free plan, change nothing.

See the full page →See the tool ↗

Casdoor versus Auth0: the match

  • Price

    Casdoor

    €0 on your server

    Auth0

    €30/month (Essentials)

  • Users

    Casdoor

    Unlimited

    Auth0

    500 active a month on Essentials, then more

  • Two factor authentication

    Casdoor

    Included

    Auth0

    Pro version from Essentials

Auth0 ↗

The prompt that installs Casdoor

Paste this prompt into Claude: it checks the repository, asks you its questions and installs the tool step by step.

Installe Casdoor sur mon serveur : c'est le serveur d'identité open source qui remplace Auth0 (dépôt GitHub casdoor/casdoor, site casdoor.ai). N'utilise pas l'image casdoor-all-in-one, réservée aux essais : installe l'image officielle casbin/casdoor avec une base PostgreSQL ou MySQL dans Docker Compose, en suivant la documentation du dépôt, sur la dernière version publiée, et place-le derrière mon nom de domaine en HTTPS. Dès la première connexion, remplace le mot de passe administrateur par défaut (admin / 123) par un mot de passe long et active la double authentification sur ce compte. Mets l'interface en français. Crée ensuite une organisation et une application pour mon site, active la connexion par e-mail et avec Google, et montre-moi comment brancher mon appli avec OpenID Connect. Casdoor corrige souvent des failles de sécurité : prépare une commande de mise à jour que je lancerai chaque semaine, avec une sauvegarde de la base avant chaque mise à jour, et montre-moi comment être prévenu des nouvelles versions sur GitHub. Explique chaque étape simplement, je débute.

Review the GitHub repository and check whether it is safe to install given my machine and my infrastructure. Ask me as many questions as possible, using widgets, to clarify my request and be as precise as you can.

Frequently asked questions

Is Casdoor really free?
Yes. Casdoor is open source: the code is public and installing it costs nothing. At most you pay for hosting if you put it on a server, often a few euros a month. Auth0, on the other hand, costs €30 a month.
Do I need to code to install Casdoor?
No. The level is advanced and the install takes about 40 minutes with the prompt from the page: Claude does the work, you answer its questions.
How is it different from Auth0?
Casdoor does most of what Auth0 does, without a subscription, and your data stays with you. The point by point comparison is on the page.
Do I own my data?
Yes. With an open source tool installed on your side, your files stay on your machine or your server. Nobody can close your account or change the price.

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