Supabase Auth vs Keycloak for Solo Developers

Authentication is one of those things you never want to build from scratch. One bad decision and you are dealing with security vulnerabilities, token headaches, and angry users locked out of their accounts. For solo developers, the choice often comes down to a managed service versus a self-hosted solution. Supabase Auth and Keycloak represent two very different philosophies for solving the same problem.

Supabase Auth Overview

Supabase Auth is the authentication layer built into Supabase, the open-source Firebase alternative. It handles email/password login, magic links, OAuth providers (Google, GitHub, Discord, and more), phone auth, and row-level security policies that tie directly into your Postgres database.

The biggest draw for solo developers is how tightly it integrates with the rest of the Supabase ecosystem. Your auth users live in the same Postgres database as your app data. Row-level security means you can write policies like "users can only read their own data" without any middleware. The free tier gives you 50,000 monthly active users, which is more than enough for most indie projects.

Setup takes minutes. You enable providers in the dashboard, drop in the Supabase client library, and call supabase.auth.signInWithOAuth(). No server configuration, no Docker containers, no certificate management.

Keycloak Overview

Keycloak is an open-source identity and access management solution backed by Red Hat. It supports OAuth 2.0, OpenID Connect, SAML 2.0, LDAP, Active Directory, and fine-grained role-based access control. Enterprise teams use it to manage authentication across dozens of internal services.

Keycloak runs as a standalone Java application. You deploy it yourself (typically via Docker), configure realms, clients, and roles through its admin console, and connect your applications using standard OIDC flows. It is incredibly powerful and handles complex scenarios like multi-tenancy, custom authentication flows, identity brokering, and user federation.

The tradeoff is complexity. Keycloak has a steep learning curve. Configuration involves realms, clients, scopes, mappers, and flows. The admin console has hundreds of settings. Running it in production means managing a Java process, a database (usually Postgres), TLS certificates, and keeping it updated for security patches.

Comparison Table

When to Pick Supabase Auth

Choose Supabase Auth if you are already using Supabase for your database, or if you want the fastest path to working authentication. It is the better choice when:

• You are building a single web or mobile application.
• You want email/password, magic links, or social OAuth without configuration headaches.
• Row-level security in Postgres appeals to you as an authorization model.
• You do not need SAML, LDAP, or complex multi-tenant setups.
• You value zero maintenance and want to focus on building features.

For a typical SaaS or side project, Supabase Auth gets you from zero to "users can sign in" in under 30 minutes, including social providers.

When to Pick Keycloak

Choose Keycloak if you need enterprise-grade identity management or your project has specific requirements that Supabase Auth cannot handle:

• You are building a platform with multiple services that all need centralized authentication.
• You need SAML 2.0 for enterprise SSO integrations.
• Your app requires custom authentication flows (step-up auth, conditional MFA, custom token claims).
• You want full control over your user data and authentication infrastructure.
• Multi-tenancy with isolated realms is a requirement.

Be honest about whether you actually need these features. Most solo developers do not, and the operational overhead of running Keycloak is significant. You are committing to managing a Java application in production, keeping it patched, and debugging OIDC configuration issues.

Verdict

For the vast majority of solo developers, Supabase Auth is the clear winner. It removes the operational burden entirely, integrates beautifully with Postgres, and covers every authentication pattern a typical web or mobile app needs. The free tier is generous, and upgrading is straightforward.

Keycloak is the right tool when you genuinely need its enterprise capabilities. If you are building something that requires SAML, complex RBAC across multiple services, or custom authentication flows, it is unmatched. But if you are a solo developer asking "which auth should I use for my SaaS?" the answer is almost certainly not Keycloak. Save yourself the infrastructure headache and ship faster with Supabase Auth.