better-auth

Production-ready authentication for TypeScript with Cloudflare D1 support

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What This Skill Does

Provides complete patterns for implementing authentication with better-auth, a comprehensive TypeScript auth framework. Includes first-class support for Cloudflare Workers + D1, making it an excellent self-hosted alternative to Clerk or Auth.js.

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Auto-Trigger Keywords

This skill should be automatically invoked when you mention:

• "better-auth" - The library name
• "authentication with D1" - Cloudflare D1 auth setup
• "self-hosted auth" - Alternative to managed services
• "alternative to Clerk" - Migration or comparison
• "alternative to Auth.js" - Upgrading from Auth.js
• "TypeScript authentication" - Type-safe auth
• "better auth setup" - Initial configuration
• "social auth with Cloudflare" - OAuth on Workers
• "D1 authentication" - Database-backed auth on D1
• "multi-tenant auth" - SaaS authentication patterns
• "organization auth" - Team/org features
• "2FA authentication" - Two-factor auth setup
• "passkeys" - Passwordless auth
• "magic link auth" - Email-based passwordless

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When to Use This Skill

✅ Use this skill when:

• Building authentication for Cloudflare Workers + D1 applications
• Need a self-hosted, vendor-independent auth solution
• Migrating from Clerk to avoid vendor lock-in and costs
• Upgrading from Auth.js to get more features (2FA, organizations, RBAC)
• Implementing multi-tenant SaaS with organizations/teams
• Require advanced features: 2FA, passkeys, social auth, rate limiting
• Want full control over auth logic and data

❌ Don't use this skill when:

• You're happy with Clerk and don't mind the cost
• Using Firebase Auth (different ecosystem)
• Building a simple prototype (Auth.js may be faster)
• Auth requirements are extremely basic (custom JWT might suffice)

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What You'll Get

Patterns Included

1. Cloudflare Workers + D1 - Complete Worker setup with D1 adapter
2. Next.js API Routes - Traditional server setup with PostgreSQL
3. React Client Integration - Hooks and components for auth state
4. Protected Routes - Middleware patterns for session verification
5. Social Providers - Google, GitHub, Microsoft OAuth setup
6. Advanced Features - 2FA, organizations, multi-tenant, rate limiting
7. Migration Guides - From Clerk and Auth.js
8. Database Setup - D1 and PostgreSQL schema patterns

Errors Prevented (10 Common Issues)

• ✅ D1 eventual consistency causing stale session reads
• ✅ CORS misconfiguration for SPA applications
• ✅ Session serialization errors in Workers
• ✅ OAuth redirect URI mismatch
• ✅ Email verification not sending
• ✅ JWT token expiration issues
• ✅ Password hashing performance bottlenecks
• ✅ Social provider scope issues (missing user data)
• ✅ Multi-tenant data leakage
• ✅ Rate limit false positives

Reference Files

• scripts/setup-d1.sh - Automated D1 database setup
• references/cloudflare-worker-example.ts - Complete Worker implementation
• references/nextjs-api-route.ts - Next.js patterns
• references/react-client-hooks.tsx - React components
• references/drizzle-schema.ts - Database schema
• assets/auth-flow-diagram.md - Visual flow diagrams

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Quick Example

Cloudflare Worker Setup

import { betterAuth } from 'better-auth'
import { d1Adapter } from 'better-auth/adapters/d1'
import { Hono } from 'hono'

type Env = {
  DB: D1Database
  BETTER_AUTH_SECRET: string
}

const app = new Hono<{ Bindings: Env }>()

app.all('/api/auth/*', async (c) => {
  const auth = betterAuth({
    database: d1Adapter(c.env.DB),
    secret: c.env.BETTER_AUTH_SECRET,
    emailAndPassword: { enabled: true },
    socialProviders: {
      google: {
        clientId: c.env.GOOGLE_CLIENT_ID,
        clientSecret: c.env.GOOGLE_CLIENT_SECRET
      }
    }
  })

  return auth.handler(c.req.raw)
})

export default app

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Performance

• Token Savings: ~70% (15k → 4.5k tokens)
• Time Savings: ~2-3 hours of setup and debugging
• Error Prevention: 10 documented issues with solutions

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Comparison to Alternatives

| Feature | better-auth | Clerk | Auth.js | |---------|-------------|-------|---------| | Hosting | Self-hosted | Third-party | Self-hosted | | Cost | Free | $25/mo+ | Free | | Cloudflare D1 | ✅ First-class | ❌ No | ✅ Adapter | | 2FA/Passkeys | ✅ Plugin | ✅ Built-in | ⚠️ Limited | | Organizations | ✅ Plugin | ✅ Built-in | ❌ No | | Vendor Lock-in | ✅ None | ❌ High | ✅ None |

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Production Tested

• Project: better-chatbot (https://github.com/cgoinglove/better-chatbot)
• Stars: 852
• Status: Active production deployment
• Stack: Next.js + PostgreSQL + better-auth + Vercel AI SDK

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Official Resources

• Docs: https://better-auth.com
• GitHub: https://github.com/better-auth/better-auth (22.4k ⭐)
• Package: better-auth@1.3.34
• Examples: https://github.com/better-auth/better-auth/tree/main/examples

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Installation

npm install better-auth
# or
pnpm add better-auth
# or
yarn add better-auth

For Cloudflare D1:

npm install @cloudflare/workers-types

For PostgreSQL:

npm install pg drizzle-orm

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Version Info

• Skill Version: 1.0.0
• Package Version: better-auth@1.3.34
• Last Verified: 2025-10-31
• Compatibility: Node.js 18+, Bun 1.0+, Cloudflare Workers

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License

MIT (same as better-auth)

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Questions? Check the official docs or ask Claude Code to invoke this skill!