Better Auth vs Clerk vs NextAuth vs Supabase Auth (2026)

If you are choosing Better Auth vs Clerk vs NextAuth vs Supabase Auth for a Next.js SaaS in 2026, you are really choosing a deployment model: self-hosted library, managed product, legacy Auth.js install, or Supabase-bundled identity. This guide gives a clear verdict, verified pricing, a feature matrix, and decision rules we use when shipping auth in TurboStarter.

What is Better Auth vs Clerk vs NextAuth vs Supabase Auth?

Four names dominate Next.js auth searches. They solve the same problem with different ownership models.

Quotable definition: Better Auth and Auth.js are libraries you run. Clerk is a managed SaaS. Supabase Auth is platform auth that shines when RLS is part of your data model.

Quick comparison table

Sources: Better Auth docs, Clerk pricing, Auth.js migration guidance, Supabase Auth docs / Supabase pricing.

Pricing: what you actually pay at scale

Auth pricing arguments go stale fast. Use current published plans, not 2024 blog math.

Clerk (MRU, not classic MAU)

Clerk bills Monthly Retained Users (MRUs). A user who signs up and never returns after the first day does not count toward MRU (Clerk pricing FAQ).

Organizations: 100 MROs included; Enhanced B2B Authentication add-on is $100/mo ($85 annual) for higher org limits and advanced org features (Clerk pricing).

Better Auth and NextAuth

Both are open source. Your bill is Postgres + compute + email/SMS. At ~100k monthly active users, teams typically pay tens of dollars for a managed Postgres instance, not a four-figure auth invoice. You own ops: sessions, rate limits, migrations, monitoring.

Supabase Auth

Auth is included in the Supabase plan:

SSO MAU and advanced phone MFA are separate line items on paid plans (Supabase pricing, MAU usage docs).

Rule of thumb: Under ~50k retained users, Clerk can feel “free.” Past that, self-hosted Better Auth or Supabase’s overage rates usually win on pure cost, unless Clerk’s UI and dashboard are buying you engineering weeks every quarter.

Better Auth: self-hosted, TypeScript-first, plugin-rich

Better Auth is a framework-agnostic authentication and authorization library for TypeScript. Official docs position it as batteries-included (email/password, sessions, social sign-on, orgs, 2FA) plus a plugin ecosystem for passkeys, magic links, and more (introduction).

Why teams pick it in 2026

• User and session tables live next to orgs and billing in your schema (Drizzle/Prisma adapters)
• Organizations and access control are first-class, not a weekend side project
• No per-MAU tax as you grow
• Works across Next.js, Expo, and other runtimes: one auth package for multi-platform products
• Aligns with the Auth.js succession story after the Auth.js joins Better Auth announcement (Sep 22, 2025)

Tradeoffs

• You operate it: migrations, email delivery, rate limiting, abuse controls
• No Clerk-grade hosted dashboard out of the box
• UI is DIY or Better Auth UI / starter-kit screens

TurboStarter ships Better Auth with password, magic link, OTP, passkeys, anonymous auth, OAuth, 2FA, and organization flows already wired. See the auth overview and the Next.js Better Auth template.

Clerk: fastest path to polished auth UI

Clerk is the managed option: prebuilt sign-in/sign-up/user profile components, organizations, MFA, passkeys, enterprise connections, and an admin dashboard. For a solo founder who needs B2B-looking auth this week, Clerk still wins on time-to-production.

Why teams pick it

• Best-in-class React components and drop-in middleware patterns
• Hosted user management, device sessions, and webhooks
• Enterprise SSO connections on Pro+ with published overage pricing
• SOC 2 report available on Business plan (Clerk pricing)

Tradeoffs

• Users live in Clerk’s system (migration is a project)
• Cost scales with retained users; B2B/org add-ons stack on top
• You accept product roadmap and regional constraints of a vendor

Pick Clerk when engineering hours are scarcer than MRU fees for the next 12 months.

NextAuth / Auth.js: keep it if it works, don’t start here

NextAuth.js (Auth.js) powered a huge share of the Next.js ecosystem for years. In September 2025, Auth.js became part of Better Auth. The Auth.js site and migration guide are explicit: existing apps can stay; new projects should prefer Better Auth; Better Auth continues security patches for Auth.js (migrate to Better Auth).

Why it still appears in comparisons

• Massive installed base and OAuth provider breadth
• Familiar patterns in older boilerplates and tutorials
• Zero license cost, self-hosted

Why greenfield teams move on

• MFA, passkeys, magic links, and organizations usually mean custom work
• Direction and DX energy shifted to Better Auth’s plugin model
• Dual maintenance (Auth.js + Better Auth) is unnecessary for new apps

If you are on Auth.js and stable, do not rewrite for fashion. If you are starting today, skip straight to Better Auth.

Supabase Auth: right answer when Supabase is the platform

Supabase Auth issues JWTs and stores users in your project’s Postgres. Its killer feature is Row Level Security: policies can reference the authenticated user directly, and client requests carry the auth token into PostgREST (Supabase Auth docs).

Why teams pick it

• Zero extra auth vendor if you already use Supabase DB, Storage, or Realtime
• Generous free MAU quota; cheap overages on Pro
• Social providers, MFA, magic links, and paid SSO in one console

Tradeoffs

• Organizations / multi-tenancy are mostly your schema and policies
• UI is functional, not Clerk-polished
• Choosing Supabase “just for auth” while running a separate Postgres elsewhere adds accidental complexity

TurboStarter can connect to Supabase as a database host without making Supabase Auth the identity layer. See connect TurboStarter to Supabase. Auth stays Better Auth + your tables unless you intentionally adopt the Supabase auth stack.

Feature depth: MFA, orgs, UI, and multi-platform

Multi-factor and passkeys

Organizations and B2B

Better Auth and Clerk treat orgs as product primitives. Auth.js and Supabase leave tenancy to your app (or a kit). Clerk’s free org tier caps members/MROs; heavier B2B needs the Enhanced add-on. Better Auth’s organization plugin keeps membership in your DB, the model TurboStarter uses for invites, roles, and seats (organizations docs).

UI and DX

Clerk wins raw component polish. Better Auth + Better Auth UI (shadcn registry) closes much of the gap while keeping owned source. Auth.js and Supabase expect more custom forms.

Web, mobile, extension

If you need one auth story across Next.js, Expo, and a browser extension, a self-hosted library in a shared package beats bolting Clerk or Supabase Auth onto three clients separately. That multi-platform path is why TurboStarter standardizes on Better Auth in a Turborepo (best SaaS stack 2026, cross-platform SaaS).

Decision framework: which auth should you pick?

Use this in order. Stop at the first hard yes.

Situation → pick cheat sheet

Common mistakes when comparing these four

1. Using outdated Clerk free-tier numbers: Hobby/Pro include 50k MRUs, not the old 10k MAU talking point.
2. Treating Auth.js as abandoned: it is maintained for security; it is simply not the feature roadmap for new apps.
3. Picking Supabase Auth without Supabase: you inherit platform coupling without the RLS payoff.
4. Ignoring UI cost on Better Auth: budget a day for Better Auth UI or a starter; do not compare “Clerk in 15 minutes” to “raw Better Auth with zero screens.”
5. Forgetting email/SMS: magic links and OTP fail in production without a real provider (Resend, etc.), regardless of library.
6. Optimizing only for setup time: auth migrations after launch are painful; price lock-in and data ownership on day one.

Frequently asked questions

Final verdict: Better Auth vs Clerk vs NextAuth vs Supabase Auth

Better Auth vs Clerk vs NextAuth vs Supabase Auth is a ownership-and-platform decision, not a popularity contest.

• Choose Better Auth for greenfield TypeScript SaaS where the user table should live beside your product data (the default we ship in TurboStarter).
• Choose Clerk when managed UI and dashboard speed justify MRU pricing and lock-in.
• Choose Supabase Auth when Supabase + RLS is already your backend story.
• Keep NextAuth / Auth.js when migration cost exceeds plugin gains; start new work on Better Auth.

If auth is only one blocker next to billing, orgs, and admin, skip assembling four vendors yourself: skim the best SaaS stack for 2026, the Better Auth UI guide, the Next.js security guide, or open TurboStarter and ship with production auth already configured.