OpenAPI Integration

Better Auth includes a built-in OpenAPI plugin that generates documentation for all auth endpoints. This guide shows how to set it up and combine it with your Glasswork API documentation.

Setup

1. Install the OpenAPI Plugin

The OpenAPI plugin is included with Better Auth:

// src/auth/auth.config.ts
import { betterAuth } from 'better-auth';
import { openAPI } from 'better-auth/plugins';
import { prismaAdapter } from 'better-auth/adapters/prisma';

export const auth = betterAuth({
  database: prismaAdapter(prisma, { provider: 'postgresql' }),
  emailAndPassword: { enabled: true },
  plugins: [
    openAPI(), // Add the OpenAPI plugin
  ],
});

2. Access the Reference

Once configured, Better Auth exposes:

Endpoint	Description
/api/auth/reference	Interactive API reference (Scalar)
/api/auth/open-api/generate-schema	Raw OpenAPI JSON schema

Navigate to http://localhost:3000/api/auth/reference to see the interactive documentation.

Endpoints Documentation

The OpenAPI plugin automatically documents:

• Core Authentication: Sign up, sign in, sign out, session management
• Email/Password: Password reset, email verification
• Social OAuth: Provider-specific endpoints
• Plugin Endpoints: 2FA, magic links, passkeys, organizations, etc.

Endpoints are grouped by plugin name, with core endpoints under "Default" and model schemas under "Models".

Getting the Schema Programmatically

Generate the OpenAPI schema in code:

import { auth } from './auth.config';

const openAPISchema = await auth.api.generateOpenAPISchema();
console.log(JSON.stringify(openAPISchema, null, 2));

This returns a complete OpenAPI 3.0 specification object.

Combining with Glasswork Routes

To show both your API routes and auth routes in a single documentation UI, use Scalar's multiple sources feature:

import { Scalar } from '@scalar/hono-api-reference';
import { bootstrap } from 'glasswork/core';

const { app } = await bootstrap(AppModule, {
  openapi: {
    enabled: true,
    serveSpecs: true,    // Serves at /api/openapi.json
    serveUI: false,      // We'll use custom Scalar instead
  },
});

// Mount auth routes
app.route('/api/auth', authRoutes);

// Custom Scalar with multiple sources
app.get('/docs', Scalar({
  pageTitle: 'API Documentation',
  sources: [
    {
      url: '/api/openapi.json',
      title: 'API'
    },
    {
      url: '/api/auth/open-api/generate-schema',
      title: 'Auth'
    },
  ],
}));

Now /docs shows a tabbed interface with both API and Auth documentation.

Configuration Options

The OpenAPI plugin accepts configuration:

import { openAPI } from 'better-auth/plugins';

plugins: [
  openAPI({
    // Customize the reference page title
    // pageTitle: 'Auth API Reference',
  }),
],

Security Schemes

Better Auth's OpenAPI spec includes security scheme definitions. When combining with Glasswork routes, ensure your security schemes are consistent:

// In Glasswork bootstrap options
openapi: {
  documentation: {
    components: {
      securitySchemes: {
        cookieAuth: {
          type: 'apiKey',
          in: 'cookie',
          name: 'session',
          description: 'Session cookie from Better Auth',
        },
        bearerAuth: {
          type: 'http',
          scheme: 'bearer',
          description: 'JWT token from Better Auth',
        },
      },
    },
  },
},

Writing Schema to File

For CI/CD or client generation, write the combined schema:

// scripts/generate-openapi.ts
import { auth } from '../src/auth/auth.config';
import fs from 'fs';

async function generateSchemas() {
  // Auth schema
  const authSchema = await auth.api.generateOpenAPISchema();
  fs.writeFileSync(
    'openapi-auth.json',
    JSON.stringify(authSchema, null, 2)
  );

  console.log('Generated openapi-auth.json');
}

generateSchemas();

Add to your build scripts:

{
  "scripts": {
    "build:openapi": "tsx scripts/generate-openapi.ts",
    "build": "pnpm build:openapi && tsc"
  }
}

Route Security in Glasswork

Mark routes as public or protected for correct OpenAPI security documentation:

// Public route - no security requirements in OpenAPI
router.post('/auth/callback', ...route({
  public: true,
  handler: async ({ body }) => {
    // OAuth callback handling
  },
}));

// Protected route - includes security schemes in OpenAPI
router.get('/profile', ...route({
  // public: false (default)
  authorize: { action: 'read', subject: 'User' },
  handler: async ({ user }) => {
    return user;
  },
}));

Best Practices

Consistent Base Paths

Mount auth routes under a consistent path:

// All auth routes under /api/auth
app.route('/api/auth', authRoutes);

// Your API routes under /api
app.route('/api/projects', projectRoutes);
app.route('/api/users', userRoutes);

Environment-Specific Docs

Disable docs in production:

import { isProduction } from 'glasswork/core';

if (!isProduction()) {
  app.get('/docs', Scalar({
    sources: [
      { url: '/api/openapi.json', title: 'API' },
      { url: '/api/auth/open-api/generate-schema', title: 'Auth' },
    ],
  }));
}

Tag Organization

Use consistent tags across your API and auth routes. Better Auth groups by plugin name; organize your routes similarly:

router.get('/users', ...route({
  tags: ['Users'],  // Matches organizational style
  // ...
}));

Next Steps

• Testing - Test auth flows and integration
• OpenAPI Routes - Glasswork's OpenAPI configuration