Nestjs Better Auth Module

A better-auth Nestjs module that supports Fastify and Express v5 http-adapters out of the box.

Getting Started

Installing the library

pnpm i nestjs-better-auth

HTTP Adapters Support

This module supports two HTTP adapters out of the box:

• Express v5

  • Better Auth Integration guide for Express
  • Default adapter for NestJS applications

• Fastify

  • Better Auth Integration guide for Fastify
  • Higher performance alternative

Please refer to the respective integration guides for detailed setup instructions.

Consuming BetterAuthModule

Simply register the module in your AppModule (or your feature)

import { Module } from '@nestjs/common';
import { BetterAuthModule } from 'nestjs-better-auth';

@Module({
  imports: [
    BetterAuthModule.forRoot({
      betterAuthConfig: {
        emailAndPassword: {
          enabled: true,
        },
      },
    }),
  ],
})
class AppModule {}

You can also leverage forRootAsync if you need to inject any configuration/third-party value to build your config.

Authentication Guard / Protecting your routes

This library exposes a BetterAuthGuard to protect authenticated routes. To use it globally for all routes, register it as follows:

import { Module } from '@nestjs/common';
import { BetterAuthModule, BetterAuthGuard } from 'nestjs-better-auth';

@Module({
  imports: [
    BetterAuthModule.forRoot({
      betterAuthConfig: {
        emailAndPassword: {
          enabled: true,
        },
        // ...your configuration
      },
    }),
  ],
  providers: [
    {
      provide: 'APP_GUARD',
      useClass: BetterAuthGuard,
    },
  ],
})
class AppModule {}

Some routes should be publicly accessible without session validation. You can provide a decorator token to the module to specify which routes should skip authentication. Alternatively, you can create your own Auth guard or apply the existing one manually to specific controllers or routes.

Example:

import { Controller, Get, SetMetadata, Module } from '@nestjs/common';

const PublicRouteToken = Symbol('publicRoute');
const IsPublic = () => SetMetadata(PublicRouteToken, true);

@Controller()
class MyController {
  @IsPublic()
  @Get()
  publicRoute() {}

  @Get()
  authenticatedRoute() {}
}

@Module({
  imports: [
    BetterAuthModule.forRoot({
      skipAuthDecoratorMetadataKey: PublicRouteToken,
      betterAuthConfig: {
        emailAndPassword: {
          enabled: true,
        },
      },
    }),
  ],
  providers: [
    {
      provide: 'APP_GUARD',
      useClass: BetterAuthGuard,
    },
  ],
})
class AppModule {}

Why not full ESM?

We're maintaining CommonJS compatibility as many existing applications still use CJS. While we plan to transition to ESM in the future, this approach ensures broader compatibility for now.

HOOKS

WIP

Read authenticated user

You can read the authenticated/current user session using @CurrentUserSession decorator. By default, it will return the user and session but it accepts a parameter user or session, examples below

import { CurrentUserSession, BetterAuthUserSession } from 'nestjs-better-auth';
import { Controller } from '@nestjs/common';

class Controller {
  @Get('me')
  getMe(
    @CurrentUserSession() userAndSession: BetterAuthUserSession,
    @CurrentUserSession('user') user: BetterAuthUserSession['user'],
    @CurrentUserSession('session') session: BetterAuthUserSession['session'],
  ) {
    // your logic
  }
}

Contributing

We welcome contributions to improve nestjs-better-auth! Here's how you can help:

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

Please ensure you follow our coding standards and include appropriate tests for new features.