Better Auth vs NextAuth in 2026: when to migrate

For years, NextAuth (now Auth.js) was the default answer when someone asked "what should I use for auth in Next.js?". In 2026 that answer is no longer automatic. Better Auth has matured enough to be the reasonable default in new projects, and the decision to migrate from Auth.js is worth thinking through.

This guide compares both without marketing. When Better Auth wins, when NextAuth/Auth.js still makes sense, and how to decide whether to migrate.

What they have in common

• Work with Next.js (App Router and Pages)
• OAuth (Google, GitHub, Discord, etc.)
• Email + password
• httpOnly cookie sessions
• Multiple adapter support (Prisma, Drizzle, etc.)

At the "basic auth" level, either works. The difference shows up when you push the product past demo stage.

Where Better Auth clearly wins

1. Official plugins that cover real SaaS features:

• twoFactor() — TOTP + backup codes in 30 minutes
• organization() — multi-tenancy with roles and invitations
• magicLink() — passwordless login
• passkey() — native WebAuthn / Passkeys
• admin() — impersonate, ban, session reads

In NextAuth you build all of these by hand or rely on third-party packages that may break in the next version.

2. End-to-end type safety:

import { auth } from '@/lib/auth/server';
const session = await auth.api.getSession({ headers: await headers() });
// session.user.id is string, not any
// session.activeOrganizationId is typed if the organization plugin is on

NextAuth v4 was halfway typed. v5/Auth.js improves it but still requires type augmentations in multiple places. Better Auth infers them from the active plugins.

3. Readable errors:

When something fails, Better Auth returns a concrete message: "Email not verified", "Invalid 2FA code". NextAuth/Auth.js still throws generic errors in some paths that you debug with the docs open.

4. Real edge runtime:

Better Auth works on edge without a special DB adapter. Auth.js works on edge only if your adapter supports it, and sometimes you end up configuring two clients.

Where NextAuth/Auth.js wins

1. Community and documentation:

NextAuth has been around for years. Search for "next.js + auth + anything" and you'll find a tutorial. Better Auth has been stable for a little over a year; tutorials are fewer and you sometimes need to read the official docs.

2. Maturity of exotic providers:

If you need to integrate with a niche OAuth provider (Twitch, Spotify, some corporate one), NextAuth has more provider configs out of the box.

3. If it's already working and you don't migrate soon:

Migrating Auth.js → Better Auth in an app with thousands of users costs time. If Auth.js covers your needs today, it's not urgent.

When to migrate

Migrate if:

• You're starting a new project (the decision is trivial)
• Your app needs 2FA, multi-tenancy, or admin features you currently build by hand
• You've lost more than 4 hours debugging Auth.js in the last 3 months
• Your team spends time maintaining auth integrations that aren't your product anymore

Don't migrate if:

• Auth.js covers 100% of what you need and the app is mature
• You have < 2 weeks of runway before an important release (not the time to touch auth)
• The migration cost (tests, existing-session edge cases) outweighs the pain you'd avoid

What a migration looks like

If you decide to migrate, the sane path:

1. Keep Auth.js running while you test Better Auth on a new endpoint.
2. Data: users, sessions, accounts tables. Better Auth can use the same Prisma adapter; model names get mapped via config.
3. Session migration: existing Auth.js sessions don't carry over. Communicate that users need to log back in (one email is enough).
4. Per-feature rollout: new signup → Better Auth, old login → Auth.js for a week, then flip completely.

In an app of 5-10k users, it's ~2-3 days of work if your auth was already well encapsulated. More if auth is sprinkled throughout the code.

Common migration mistakes

1. Not communicating the "please log in again": users discover the next day that their session doesn't work and open a ticket. Email them 48h ahead.

2. Migrating without tests for the new flow: signup, login, reset password, OAuth — the 4 minimum flows must be tested before the flip.

3. Switching from Prisma to another adapter at the same time: if you piggyback ORM changes on the auth migration, you double the risk. Do them in separate steps.

Bottom line

In 2026, Better Auth is the reasonable default for new projects. NextAuth/Auth.js is still valid for mature apps where it works; migrating for fashion adds nothing.

The right question isn't "is Better Auth better?". It's "how many hours per month am I spending fighting auth, and how much of that ROI comes from the product itself?". If the second number is < 80% of the first, it's time to migrate.