Better Auth vs NextAuth vs Clerk for a B2B SaaS: An Honest Comparison

For a new B2B SaaS, pick Better Auth if you want authentication in your own database with organizations and SAML built in, Clerk if you want hosted sign-in running in a day and its per-user pricing fits, and NextAuth (Auth.js) only if your app already runs on it. Since Auth.js joined Better Auth, the team recommends Better Auth for new projects and keeps NextAuth on security and urgent fixes.

This comparison is written from the official documentation and pricing pages, checked in September 2026, and from running one of them in production: the RAITHub website uses NextAuth v4. It is engineering guidance for B2B products on Next.js, where the questions that matter are organizations (a customer company with many users), roles, enterprise single sign-on, and where user data lives. For the permissions model that sits on top of any of these, see SaaS authorization and RBAC design.

What changed with NextAuth and Better Auth?

In September 2025 the Auth.js project, which publishes NextAuth, became part of Better Auth. The Better Auth announcement says existing users "can continue doing so without disruption", that the team will "keep addressing security patches and urgent issues", and that new projects should start on Better Auth unless they need something it lacks, such as stateless sessions without a database. The Auth.js documentation now carries the banner "The Auth.js project is now part of Better Auth", and its current docs still cover next-auth@5.0.0-beta.

So NextAuth is not abandoned, but it is in maintenance. That is fine for an app already running on it. It is a weak reason to start a new product on it.

How do Better Auth, NextAuth and Clerk compare for a B2B SaaS?

Question	Better Auth	NextAuth / Auth.js	Clerk
What it is	Open-source TypeScript library (MIT)	Open-source library, now maintained by the Better Auth team	Hosted authentication service with UI components
Where user data lives	Your database	Your database, or only in a signed cookie (JWT sessions)	Clerk's infrastructure
Organizations and members	Organization plugin: members, invitations, roles, teams	Not built in; you model it yourself	Built in; 20 members per organization before the B2B add-on
Enterprise SSO (SAML)	SSO plugin: OIDC, OAuth2 and SAML 2.0	OAuth and OIDC providers; SAML needs a separate service	1 enterprise connection on Pro, then $75/month each
Passkeys and 2FA	Plugins	WebAuthn sign-in is listed; 2FA is yours to build	Built in
Cost	Free; you pay for your own hosting and database	Free; same	Free to 50,000 monthly retained users; Pro from $25/month
Maintenance status (Sept 2026)	Active	Security patches and urgent issues	Active commercial product
Time to working sign-in	Hours to a day	Hours to a day	Under an hour with prebuilt components

Sources: Better Auth introduction, organization plugin, SSO plugin, the Better Auth repository for the MIT licence, the Auth.js docs, and Clerk pricing. The time-to-sign-in row is RAITHub's engineering estimate, not a vendor claim.

When is Better Auth the right choice?

When you want to own the user table and need B2B features without building them. Better Auth describes itself as "a framework-agnostic, universal authentication and authorization framework for TypeScript". For a B2B product, two plugins do most of the work:

• Organization plugin. Organizations, members, invitations with expiry, the default owner, admin and member roles, custom roles, optional teams, and access control that maps actions to resources.
• SSO plugin. The docs say it "supports OpenID Connect (OIDC), OAuth2 providers, and SAML 2.0", with domain verification and organization provisioning, so a customer's staff can sign in through their company identity provider and land in the right organization.

A minimal setup against your own PostgreSQL database looks like this:

// lib/auth.ts
import { betterAuth } from 'better-auth'
import { organization } from 'better-auth/plugins'
import { Pool } from 'pg'

export const auth = betterAuth({
  database: new Pool({ connectionString: process.env.DATABASE_URL }),
  emailAndPassword: { enabled: true },
  plugins: [organization()],
})

The trade-off is that you run it. Password hashing, rate limiting on sign-in, session storage, email delivery for invitations and resets, and the security of your database are your responsibility. That is normal for a SaaS team, but it is work a hosted service would do for you.

When is Clerk the right choice?

When speed to a polished sign-in matters more than owning the auth layer, and the pricing works at your expected scale. Clerk hosts the user store and gives you prebuilt sign-in, user profile and organization-switcher components.

From Clerk's pricing page in September 2026:

• Hobby: free, 50,000 monthly retained users per app, 100 monthly retained organizations, up to 20 members per organization.
• Pro: $25/month ($20 billed annually), 50,000 users included, then $0.02 per user per month from 50,001 to 100,000. One enterprise connection (SAML, OIDC) included, additional ones $75/month each.
• Business: $300/month ($250 billed annually).
• B2B add-on: $100/month ($85 annually) for unlimited members per organization and custom roles.

For a B2B product, the enterprise connection line is the one to model. If you expect ten enterprise customers who each want SAML, that is nine extra connections at $75, or $675/month on top of the plan, before user overage. That can be entirely reasonable; just price it in before you choose.

In the app, Clerk gives you the user and the active organization on the server:

import { auth } from '@clerk/nextjs/server'

export async function GET() {
  const { userId, orgId } = await auth()
  if (!userId || !orgId) return new Response('Unauthorized', { status: 401 })
  // Scope every query by orgId, the customer company.
}

The trade-off is dependency. Your users live in someone else's system, and moving off later means a user export and a password-hash migration plan.

When is NextAuth still the right choice?

When the app already runs on it and works. The RAITHub website is a good example. Its admin area uses NextAuth v4 (4.24) with a credentials provider, JWT sessions that expire after 8 hours, bcrypt password hashes, a dummy-hash comparison so an unknown email costs the same time as a wrong password, and three rate-limit buckets on login (per email and IP, per IP, per account). That is a small, stable surface with one kind of user. Migrating it would add risk and no feature the site needs.

NextAuth has also cost this site real time. Its v4 peer dependency on nodemailer caused the npm ERESOLVE conflict documented on this blog, and checking its token in Next.js 16's new proxy file has its own pitfalls, covered in proxy.ts not running.

For a new B2B SaaS, NextAuth's gaps are the ones B2B needs most: no organizations, no roles, no SAML. You would build those yourself, on a library whose maintainers recommend something else for new work.

Does the choice affect tenant isolation?

Less than people think. All three tell you who the user is and, for Better Auth and Clerk, which organization is active. None of them stops your queries from reading another tenant's rows. That still has to happen in your code and database: resolve the tenant from the verified session, scope every query by it, and back it with row-level security. The PostgreSQL row-level security guide covers the database side, and users can see another tenant's data covers what goes wrong when it is missing.

One practical difference: with Better Auth, organizations are rows in your own database, so your tenant foreign keys can point at them directly. With Clerk, you store Clerk's organization ID in your tables and keep your records in sync through its webhooks.

Which should you pick? A decision table

Your situation	Pick	Why
New B2B SaaS, want user data in your own Postgres	Better Auth	Organizations and SAML as plugins; no per-user fee
New product, small team, launch in weeks, expected users well under 50,000	Clerk	Hosted UI and organizations; free or $25/month at that scale
Many enterprise customers each needing SAML	Better Auth, or Clerk with the connection cost modelled	Clerk charges $75/month per extra connection
Existing app on NextAuth, working, one user type	Stay on NextAuth	Still receives security patches; migration adds risk
Existing app on NextAuth, now selling to companies	Plan a move to Better Auth	You need organizations and SSO, and Better Auth has published a migration guide
Data residency or a customer contract requires user data in your infrastructure	Better Auth	Nothing leaves your database

Why RAITHub for authentication work?

Because RAITHub has run auth in production and has built the permission layer that sits on top of it.

• Auth in production. This site's NextAuth setup: equal-time failed logins, three-bucket rate limiting without Redis, and 400+ automated tests.
• Permissions at scale. Sundor Skin, a B2B wholesale platform RAITHub built, has 88 permission codes and 12 staff roles, with row-level security on 146 PostgreSQL tables.
• No lock-in advice. RAITHub recommends whichever option fits your users and contracts, and the code is yours either way. See the SaaS development service or the Next.js development service.

When you don't need us

• You are adding sign-in to a prototype. Follow Clerk's or Better Auth's quick start; either gets you there in an afternoon.
• Your NextAuth app works and nothing is changing. Keep it, keep it patched, and revisit when you start selling to companies.

Choosing auth for a B2B product, or moving an existing app off NextAuth? Tell RAITHub about your users and customers and book the free 15-minute technical audit.

Last reviewed: 29 September 2026. Pricing and features from the vendors' official pages on that date; check them again before you commit.

Frequently asked questions

Is NextAuth deprecated?

Not deprecated, but in maintenance. Auth.js, which publishes NextAuth, became part of Better Auth in September 2025. The team says it will keep shipping security patches and urgent fixes, and recommends Better Auth for new projects.

Is Better Auth free?

Yes. It is an open-source TypeScript library under the MIT licence. You pay only for what you run it on: your hosting, database and email provider.

How much does Clerk cost for a B2B SaaS?

Per Clerk's pricing page in September 2026: free up to 50,000 monthly retained users, Pro at $25/month, one enterprise SSO connection included on Pro and $75/month for each additional one, and a $100/month B2B add-on for unlimited members per organization.

Which one supports SAML single sign-on?

Better Auth, through its SSO plugin, which supports OIDC, OAuth2 and SAML 2.0. Clerk, as enterprise connections on paid plans. NextAuth supports OAuth and OIDC providers, but SAML needs a separate service.

Should I migrate from NextAuth to Better Auth?

Only if you need something NextAuth lacks, such as organizations, roles or SAML, or you are about to rebuild auth anyway. A working NextAuth app with one user type can stay put while it receives security patches.

Does my auth library handle tenant isolation?

No. It tells you who the user is and which organization is active. Scoping every query by tenant, and enforcing it with row-level security, is still your application's and database's job.