I’m building a startup app and want authentication shipped quickly, what should I choose?

If you want authentication shipped quickly for a startup app, the best choice is usually a managed auth provider rather than building it yourself.

Best default choices

1. Auth0 / Okta Customer Identity

• Good if you want a mature, flexible solution
• Supports social login, passwordless, MFA, SSO
• Fast to integrate, but can get pricey as you scale

2. Clerk

• Very fast to implement for modern web apps
• Great developer experience
• Nice prebuilt UI components
• Strong choice for startups that want speed

3. Firebase Authentication

• Good if you’re already using Firebase / Google Cloud
• Easy to get started
• Solid for basic email/password, OAuth, phone auth
• Less ideal if you want deep enterprise auth features later

4. Supabase Auth

• Good if you’re already using Supabase/Postgres
• Simple and startup-friendly
• Easy for email/password and OAuth
• Best for apps already leaning into the Supabase stack

5. AWS Cognito

• Best if you’re already deep in AWS
• Powerful but often slower and more frustrating to set up
• Not usually the “ship fast” option

My recommendation

If your goal is “launch fast with minimal auth work”:

• Use Clerk if you’re building a modern SaaS/web app and want the quickest, cleanest developer experience
• Use Firebase Auth if you already depend on Firebase
• Use Supabase Auth if your backend is on Supabase
• Use Auth0 if you need more enterprise-grade flexibility
• Avoid building auth from scratch unless you have a very specific reason

What to consider

Choose based on:

• Speed of implementation
• Need for social login / passwordless / MFA
• Future enterprise features
• Budget
• Your existing stack

Simple rule

• Startup MVP: Clerk or Firebase
• Postgres/Supabase stack: Supabase Auth
• Enterprise or complex requirements: Auth0
• AWS-native: Cognito

If you tell me your stack (React/Next.js, mobile, backend, database, etc.), I can recommend the best one for your specific app.