Clerk vs Auth0 vs Supabase Auth: Which Should Handle Your Logins?
Three popular ways to add authentication to an app. How Clerk (drop-in UI, great DX), Auth0 (enterprise features) and Supabase Auth (bundled with your database) compare on setup, features, pricing model, data ownership and lock-in — plus when an open-source library like Better Auth fits.
Building login yourself means handling password hashing, sessions, email verification, password resets, social login, 2FA, rate limiting and more — and getting every one right. Most apps are better off using an auth provider. (Add login to an AI-built app)
Three of the most popular are Clerk, Auth0 and Supabase Auth.
Free tiers and prices change; check each provider's pricing page. Details here are as of October 2026.
The short version
- Clerk — the fastest to add to a React/Next.js app, with polished pre-built sign-in components and user management.
- Auth0 (by Okta) — the most enterprise features: SSO, compliance, fine-grained customisation.
- Supabase Auth — part of Supabase, tightly connected to your Postgres database and its row-level security.
Side by side
| Clerk | Auth0 | Supabase Auth | |
|---|---|---|---|
| Best for | React/Next.js apps, fast setup | B2B, enterprise needs | Apps already on Supabase |
| Pre-built UI | Excellent components | Hosted login page | Basic UI helpers |
| Social login, magic links, passkeys | Yes | Yes | Yes |
| Organisations / teams | Built in | Built in | Build yourself |
| Enterprise SSO (SAML) | Paid plans | Strong | Paid plans |
| Where users are stored | Clerk | Auth0 | Your Supabase Postgres (auth schema) |
| Pricing model | Free tier, then per active user | Free tier, then per active user; enterprise is expensive | Included in Supabase plans (50,000 MAU free) |
Clerk
Add a provider and a couple of components, and you have sign-up, sign-in, user profile, organisations and session management:
import { SignedIn, SignedOut, SignInButton, UserButton } from '@clerk/nextjs'
<SignedOut><SignInButton /></SignedOut>
<SignedIn><UserButton /></SignedIn>
Strengths: developer experience, beautiful defaults, organisations for B2B, good Next.js integration. Watch for: per-user pricing beyond the free tier; user data lives with Clerk, so you'll sync what you need into your own database (usually via webhooks). (Handling webhooks reliably)
Auth0
A mature identity platform used by large companies: rules and actions to customise flows, enterprise SSO, multi-factor, compliance certifications, extensive APIs.
Strengths: the most complete feature set, especially for selling to enterprises who require SAML SSO. Watch for: complexity and cost — prices rise steeply with users and enterprise features. Often more than a small app needs.
Supabase Auth
If your app uses Supabase, auth is already there. Users live in your own Postgres database, and their identity flows straight into row-level security policies (auth.uid()), so database access rules and login are one system. (What is Supabase?, Supabase RLS explained)
Strengths: no extra service, generous free tier, your users in your database. Watch for: less polished UI components and fewer B2B features out of the box; tied to Supabase.
The open-source option
Libraries like Better Auth and Auth.js run inside your own app and store users in your own database. No per-user fees and no external dependency — but you're responsible for configuration, email delivery and keeping the library updated. A good fit for developers who want control. (Session cookies vs JWTs)
Questions to decide
- What's your stack? Supabase → Supabase Auth. Next.js without Supabase → Clerk or Better Auth.
- Selling to enterprises? SAML SSO requirements point to Auth0 or Clerk/Supabase paid tiers.
- How many users at what price? Per-active-user pricing is cheap at 1,000 users and significant at 100,000. Model it.
- Where should user data live? In your database (Supabase, open-source libraries) or with a vendor (Clerk, Auth0)?
- How painful would switching be? Migrating users between providers — especially password hashes — is possible but fiddly. Choose for the next few years.
Whatever you choose, still check
- Authorisation in your code: logging users in doesn't stop them reading each other's data. (Authentication vs authorization, IDOR explained)
- Allowed redirect URLs configured tightly. (Open redirects)
- Email deliverability for verification and resets. (Send email from your app)
EasySpawn runs your app and its Postgres database on your own server, so you can use any of these providers — or keep users in your own database with an open-source library — and Claude Code can wire it up. See how it works or join the waitlist.
Related: Add Login to an AI-Built App · Supabase vs Firebase · Session Cookies vs JWTs · What Are Passkeys?
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