import { betterAuth } from "better-auth";
import { Kysely, CamelCasePlugin } from "kysely";
import { D1Dialect } from "kysely-d1";

type Env = {
  DB: D1Database;
  BETTER_AUTH_SECRET: string;
  // ... other env vars
};

export function createAuth(env: Env) {
  return betterAuth({
    secret: env.BETTER_AUTH_SECRET,

    // Kysely with D1Dialect
    database: {
      db: new Kysely({
        dialect: new D1Dialect({
          database: env.DB,
        }),
        plugins: [
          // CRITICAL: Required if using Drizzle schema with snake_case
          new CamelCasePlugin(),
        ],
      }),
      type: "sqlite",
    },

    emailAndPassword: {
      enabled: true,
    },

    // ... other config
  });
}

// ❌ WRONG - DB binding not available outside request
const db = drizzle(env.DB, { schema }) // env.DB doesn't exist here
export const auth = betterAuth({ database: drizzleAdapter(db, { provider: "sqlite" }) })

// ✅ CORRECT - Create auth instance per-request
export default {
  fetch(request, env, ctx) {
    const db = drizzle(env.DB, { schema })
    const auth = betterAuth({ database: drizzleAdapter(db, { provider: "sqlite" }) })
    return auth.handler(request)
  }
}

import { betterAuth } from "better-auth";
import { drizzleAdapter } from "better-auth/adapters/drizzle";
import { reactStartCookies } from "better-auth/react-start";

export const auth = betterAuth({
  database: drizzleAdapter(db, { provider: "sqlite" }),
  plugins: [
    twoFactor(),
    organization(),
    reactStartCookies(), // ⚠️ MUST be LAST plugin
  ],
});

const { data: session } = authClient.useSession()

// When NOT logged in:
console.log(session) // { user: null, session: null }
console.log(!!session) // true (unexpected!)

// Correct check:
if (session?.user) {
  // User is logged in
}

import { auth } from '@/lib/auth'
import { createFileRoute } from '@tanstack/react-router'

export const Route = createFileRoute('/api/auth/$')({
  server: {
    handlers: {
      GET: ({ request }) => auth.handler(request),
      POST: ({ request }) => auth.handler(request),
    },
  },
})

import { betterAuth } from "better-auth";
import { oauthProvider } from "better-auth/plugins";
import { jwt } from "better-auth/plugins";

export const auth = betterAuth({
  plugins: [
    jwt(), // Required for token signing
    oauthProvider({
      // Token expiration (seconds)
      accessTokenExpiresIn: 3600,      // 1 hour
      refreshTokenExpiresIn: 2592000,  // 30 days
      authorizationCodeExpiresIn: 600, // 10 minutes
    }),
  ],
});

// app/api/.well-known/oauth-authorization-server/route.ts
export async function GET() {
  return Response.json({
    issuer: process.env.BETTER_AUTH_URL,
    authorization_endpoint: `${process.env.BETTER_AUTH_URL}/api/auth/oauth2/authorize`,
    token_endpoint: `${process.env.BETTER_AUTH_URL}/api/auth/oauth2/token`,
    // ... other metadata
  });
}

const client = await auth.api.createOAuthClient({
  body: {
    name: "My MCP Server",
    redirectURLs: ["https://claude.ai/callback"],
    type: "public", // or "confidential"
  },
});
// Returns: { clientId, clientSecret (if confidential) }

import { bearer } from "better-auth/plugins";
import { bearerClient } from "better-auth/client/plugins";

// Server
export const auth = betterAuth({
  plugins: [bearer()],
});

// Client - Store token after sign-in
const { token } = await authClient.signIn.email({ email, password });
localStorage.setItem("auth_token", token);

// Client - Configure fetch to include token
const authClient = createAuthClient({
  plugins: [bearerClient()],
  fetchOptions: {
    auth: { type: "Bearer", token: () => localStorage.getItem("auth_token") },
  },
});

import { oneTap } from "better-auth/plugins";
import { oneTapClient } from "better-auth/client/plugins";

// Server
export const auth = betterAuth({
  plugins: [oneTap()],
});

// Client
authClient.oneTap({
  onSuccess: (session) => {
    window.location.href = "/dashboard";
  },
});

import { anonymous } from "better-auth/plugins";

// Server
export const auth = betterAuth({
  plugins: [
    anonymous({
      emailDomainName: "anon.example.com", // temp@{id}.anon.example.com
      onLinkAccount: async ({ anonymousUser, newUser }) => {
        // Migrate anonymous user data to linked account
        await migrateUserData(anonymousUser.id, newUser.id);
      },
    }),
  ],
});

// Client
await authClient.signIn.anonymous();
// Later: user can link to real account via signIn.social/email

import { genericOAuth } from "better-auth/plugins";

export const auth = betterAuth({
  plugins: [
    genericOAuth({
      config: [
        {
          providerId: "linear",
          clientId: env.LINEAR_CLIENT_ID,
          clientSecret: env.LINEAR_CLIENT_SECRET,
          discoveryUrl: "https://linear.app/.well-known/openid-configuration",
          scopes: ["openid", "email", "profile"],
          pkce: true, // Recommended
        },
      ],
    }),
  ],
});

export const auth = betterAuth({
  rateLimit: {
    window: 60,  // seconds (default: 60)
    max: 100,    // requests per window (default: 100)

    // Custom rules for sensitive endpoints
    customRules: {
      "/sign-in/email": { window: 10, max: 3 },
      "/two-factor/*": { window: 10, max: 3 },
      "/forget-password": { window: 60, max: 5 },
    },

    // Use Redis/KV for distributed systems
    storage: "secondary-storage", // or "database"
  },

  // Secondary storage for rate limiting
  secondaryStorage: {
    get: async (key) => env.KV.get(key),
    set: async (key, value, ttl) => env.KV.put(key, value, { expirationTtl: ttl }),
    delete: async (key) => env.KV.delete(key),
  },
});

export const auth = betterAuth({
  session: {
    // Stateless: No database storage, session lives in cookie only
    storage: undefined, // or omit entirely

    // Cookie configuration
    cookieCache: {
      enabled: true,
      maxAge: 60 * 60 * 24 * 7, // 7 days
      encoding: "jwt", // Use JWT for stateless (not "compact")
    },

    // Session expiration
    expiresIn: 60 * 60 * 24 * 7, // 7 days
  },
});

import { jwt } from "better-auth/plugins";

export const auth = betterAuth({
  plugins: [
    jwt({
      // Key rotation (optional, enterprise security)
      keyRotation: {
        enabled: true,
        rotationInterval: 60 * 60 * 24 * 30, // Rotate every 30 days
        keepPreviousKeys: 3, // Keep 3 old keys for validation
      },

      // Custom signing algorithm (default: HS256)
      algorithm: "RS256", // Requires asymmetric keys

      // JWKS endpoint (auto-generated at /api/auth/jwks)
      exposeJWKS: true,
    }),
  ],
});

socialProviders: {
  google: {
    clientId: env.GOOGLE_CLIENT_ID,
    clientSecret: env.GOOGLE_CLIENT_SECRET,
    scope: ["openid", "email", "profile"], // All user data
  },
  github: {
    clientId: env.GITHUB_CLIENT_ID,
    clientSecret: env.GITHUB_CLIENT_SECRET,
    scope: ["user:email", "read:user"], // Email + full profile
  },
  microsoft: {
    clientId: env.MS_CLIENT_ID,
    clientSecret: env.MS_CLIENT_SECRET,
    scope: ["openid", "email", "profile", "User.Read"],
  },
}

export const auth = betterAuth({
  session: {
    cookieCache: {
      enabled: true,
      maxAge: 300, // 5 minutes
      encoding: "compact", // or "jwt" or "jwe"
    },
    freshAge: 60 * 60 * 24, // 1 day - operations requiring fresh session
  },
});

socialProviders: {
  // Patreon - Creator economy
  patreon: {
    clientId: env.PATREON_CLIENT_ID,
    clientSecret: env.PATREON_CLIENT_SECRET,
    scope: ["identity", "identity[email]"],
  },

  // Kick - Streaming platform (with refresh tokens)
  kick: {
    clientId: env.KICK_CLIENT_ID,
    clientSecret: env.KICK_CLIENT_SECRET,
  },

  // Vercel - Developer platform
  vercel: {
    clientId: env.VERCEL_CLIENT_ID,
    clientSecret: env.VERCEL_CLIENT_SECRET,
  },
}

undefined

Without this flag, better-auth will fail with context-related errors.

---

export const auth = betterAuth({
  databaseHooks: {
    user: {
      create: {
        before: async (user, ctx) => {
          // Validate or modify before creation
          if (user.email?.endsWith("@blocked.com")) {
            throw new APIError("BAD_REQUEST", { message: "Email domain not allowed" });
          }
          return { data: { ...user, role: "member" } };
        },
        after: async (user, ctx) => {
          // Send welcome email, create related records, etc.
          await sendWelcomeEmail(user.email);
          await createDefaultWorkspace(user.id);
        },
      },
    },
    session: {
      create: {
        after: async (session, ctx) => {
          // Audit logging
          await auditLog.create({ action: "session_created", userId: session.userId });
        },
      },
    },
  },
});

// Client setup with secure storage
import { expoClient } from "@better-auth/expo";
import * as SecureStore from "expo-secure-store";

const authClient = createAuthClient({
  baseURL: "https://api.example.com",
  plugins: [expoClient({ storage: SecureStore })],
});

// OAuth with deep linking
await authClient.signIn.social({
  provider: "google",
  callbackURL: "myapp://auth/callback", // Deep link
});

// Or use ID token verification (no redirect)
await authClient.signIn.social({
  provider: "google",
  idToken: {
    token: googleIdToken,
    nonce: generatedNonce,
  },
});

// Authenticated requests
const cookie = await authClient.getCookie();
await fetch("https://api.example.com/data", {
  headers: { Cookie: cookie },
  credentials: "omit",
});

{
  "expo": {
    "scheme": "myapp"
  }
}

trustedOrigins: ["exp://**", "myapp://"]