better-auth

# better-auth

**Status**: Production Ready
**Last Updated**: 2025-12-26
**Package**: `better-auth@1.4.9` (ESM-only)
**Dependencies**: Drizzle ORM or Kysely (required for D1)

---

## Quick Start (5 Minutes)

### Installation

**Option 1: Drizzle ORM (Recommended)**
```bash
bun add better-auth drizzle-orm drizzle-kit
```

**Option 2: Kysely**
```bash
bun add better-auth kysely @noxharmonium/kysely-d1
```

### ⚠️ v1.4.0+ Requirements

better-auth v1.4.0+ is **ESM-only**. Ensure:

**package.json**:
```json
{
  "type": "module"
}
```

**Upgrading from v1.3.x?** Load `references/migration-guide-1.4.0.md`

### ⚠️ CRITICAL: D1 Adapter Requirements

better-auth **DOES NOT** have a direct `d1Adapter()`. You **MUST** use either:
1. **Drizzle ORM** (recommended) - `drizzleAdapter()`
2. **Kysely** (alternative) - Kysely instance with D1Dialect

```typescript
// ❌ WRONG - This doesn't exist
import { d1Adapter } from 'better-auth/adapters/d1'

// ✅ CORRECT - Use Drizzle
import { drizzleAdapter } from 'better-auth/adapters/drizzle'
import { drizzle } from 'drizzle-orm/d1'
```

### Minimal Setup (Cloudflare Workers + Drizzle)

**1. Create D1 Database:**
```bash
wrangler d1 create my-app-db
```

**2. Define Schema** (`src/db/schema.ts`):
```typescript
import { integer, sqliteTable, text } from "drizzle-orm/sqlite-core";

export const user = sqliteTable("user", {
  id: text().primaryKey(),
  name: text().notNull(),
  email: text().notNull().unique(),
  emailVerified: integer({ mode: "boolean" }).notNull().default(false),
  image: text(),
});

export const session = sqliteTable("session", {
  id: text().primaryKey(),
  userId: text().notNull().references(() => user.id, { onDelete: "cascade" }),
  token: text().notNull(),
  expiresAt: integer({ mode: "timestamp" }).notNull(),
});

// See references/database-schema.ts for complete schema
```

**3. Initialize Auth** (`src/auth.ts`):
```typescript
import { betterAuth } from "better-auth";
import { drizzleAdapter } from "better-auth/adapt