The Authentication Showdown

You're building your MVP. Users need to sign in. You could spend three weeks building auth from scratch... or you could use one of these tools and ship today.

This week, we're comparing three authentication heavyweights: Auth0, Clerk, and Supabase Auth. Let's break down which one makes sense for your startup.

Auth0: The Enterprise Favorite

Best for: Teams who need enterprise features from day one

Pros:

Cons:

Pricing:

Clerk: The Developer Experience Champion

Best for: Startups shipping fast who want auth that just works

Pros:

Cons:

Pricing:

Supabase Auth: The Open Source Option

Best for: Teams already using Supabase or who want ownership

Pros:

Cons:

Pricing:

The Decision Matrix

Choose Auth0 if:

Choose Clerk if:

Choose Supabase Auth if:

Real-World Recommendation

For most early-stage startups, we'd pick Clerk. Here's why:

1. •You ship faster (pre-built components)
2. •It scales with you (generous free tier, predictable pricing)
3. •Your users get a better experience (polished UI)
4. •You can always migrate later if you hit enterprise needs

That said, if you're already deep in the Supabase ecosystem, stick with Supabase Auth. The integration is seamless and the pricing is unbeatable.

Quick Start Guide

Clerk (Next.js):

npm install @clerk/nextjs
# Add API keys to .env.local
# Wrap app in <ClerkProvider>
# Done.

Supabase (Next.js):

npm install @supabase/supabase-js
# Initialize client
# Build your own sign-in form
# Use supabase.auth.signIn()

Auth0 (Next.js):

npm install @auth0/nextjs-auth0
# Configure Auth0 dashboard
# Set up callbacks
# Add API routes
# More configuration...

The speed difference is real.

Next Week: Startup metrics that actually matter. We're cutting through the vanity metrics to show you what early-stage investors actually care about.

Stay sharp, The Startup Starter Kit Team

P.S. Using a different auth provider? Reply and tell us about your experience - we'd love to feature it.