better-auth-tenancy

Multi-tenant authentication plugin for Better Auth.

Add tenant-scoped users, per-tenant OAuth, and management APIs to your Better Auth setup.

Features

• Tenant-scoped users — the same email can exist under different tenants as separate users
• Per-tenant OAuth — store OAuth client credentials per tenant, with fallback to global providers
• Management APIs — create, update, list, and delete tenants and OAuth configs
• Better Auth native — extends schema, endpoints, and the client plugin alongside Better Auth adapters and sessions

Requirements

• Node.js 20+
• Better Auth ^1.6.16
• A supported database adapter (Drizzle, Prisma, etc.)

Installation

pnpm add better-auth-tenancy better-auth

Peer dependencies (@better-auth/core, better-call) are typically installed automatically with better-auth.

Usage

Server

import { tenantAuth } from "better-auth-tenancy";
import { betterAuth } from "better-auth";

export const auth = betterAuth({
  database: /* your adapter */,
  secret: process.env.BETTER_AUTH_SECRET,
  emailAndPassword: { enabled: true },
  plugins: [tenantAuth()],
});

Client

import { tenantAuthClient } from "better-auth-tenancy/client";
import { createAuthClient } from "better-auth/react";

export const authClient = createAuthClient({
  baseURL: process.env.NEXT_PUBLIC_APP_URL,
  plugins: [tenantAuthClient()],
});

Database schema

The plugin adds:

• tenant — tenant records
• tenantOauthConfig — per-tenant OAuth credentials
• tenantId on user, session, account, and verification

Generate and apply the schema with the Better Auth CLI:

npx @better-auth/cli generate
# then push or migrate with your ORM

By default, the global unique constraint on user.email is removed so the same address can exist under different tenants. Set keepEmailGloballyUnique: true on the plugin if you want one email to map to a single tenant globally.

Quick example

// Create a tenant
await auth.api.createTenant({
  body: { name: "Acme", slug: "acme" },
});

// Sign up under that tenant
await authClient.signUpEmailTenant({
  tenantId: tenant.id,
  email: "[email protected]",
  password: "secure-password",
  name: "Jane Doe",
});

Documentation

Full guides and API reference live in the repo under docs/. A complete Next.js example with PostgreSQL and Drizzle is in examples/nextjs-demo/.

License

MIT