better-auth

name	better-auth
description	Self-hosted auth for TypeScript/Cloudflare Workers with social auth, 2FA, passkeys, organizations, RBAC, and 15+ plugins. Requires Drizzle ORM or Kysely for D1 (no direct adapter). Self-hosted alternative to Clerk/Auth.js. Use when: self-hosting auth on D1, building OAuth provider, multi-tenant SaaS, or troubleshooting D1 adapter errors, session caching, rate limits, Expo crashes, additionalFields bugs.
user-invocable	true
allowed-tools	["Read","Write","Edit","Bash","Glob","Grep"]

better-auth - D1 Adapter & Error Prevention Guide

Package: better-auth@1.4.16 (Jan 21, 2026) Breaking Changes: ESM-only (v1.4.0), Admin impersonation prevention default (v1.4.6), Multi-team table changes (v1.3), D1 requires Drizzle/Kysely (no direct adapter)

---

⚠️ CRITICAL: D1 Adapter Requirement

better-auth DOES NOT have d1Adapter(). You MUST use:

• Drizzle ORM (recommended): drizzleAdapter(db, { provider: "sqlite" })
• Kysely: new Kysely({ dialect: new D1Dialect({ database: env.DB }) })

See Issue #1 below for details.

---

What's New in v1.4.10 (Dec 31, 2025)

Major Features:

• OAuth 2.1 Provider plugin - Build your own OAuth provider (replaces MCP plugin)
• Patreon OAuth provider - Social sign-in with Patreon
• Kick OAuth provider - With refresh token support
• Vercel OAuth provider - Sign in with Vercel
• Global backgroundTasks config - Deferred actions for better performance
• Form data support - Email authentication with fetch metadata fallback
• Stripe enhancements - Flexible subscription lifecycle, disableRedirect option

Admin Plugin Updates:

• ⚠️ Breaking: Impersonation of admins disabled by default (v1.4.6)
• Support role with permission-based user updates
• Role type inference improvements

Security Fixes:

• SAML XML parser hardening with configurable size constraints
• SAML assertion timestamp validation with per-provider clock skew
• SSO domain-verified provider trust
• Deprecated algorithm rejection
• Line nonce enforcement

📚 Docs: https://www.better-auth.com/changelogs

---

What's New in v1.4.0 (Nov 22, 2025)

Major Features:

• Stateless session management - Sessions without database storage
• ESM-only package ⚠️ Breaking: CommonJS no longer supported
• JWT key rotation - Automatic key rotation for enhanced security
• SCIM provisioning - Enterprise user provisioning protocol
• @standard-schema/spec - Replaces ZodType for validation
• CaptchaFox integration - Built-in CAPTCHA support
• Automatic server-side IP detection
• Cookie-based account data storage
• Multiple passkey origins support
• RP-Initiated Logout endpoint (OIDC)

📚 Docs: https://www.better-auth.com/changelogs

---

What's New in v1.3 (July 2025)

Major Features:

• SSO with SAML 2.0 - Enterprise single sign-on (moved to separate @better-auth/sso package)
• Multi-team support ⚠️ Breaking: teamId removed from member table, new teamMembers table required
• Additional fields - Custom fields for organization/member/invitation models
• Performance improvements and bug fixes

📚 Docs: https://www.better-auth.com/blog/1-3

---

Alternative: Kysely Adapter Pattern

If you prefer Kysely over Drizzle:

File: src/auth.ts

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
  });
}

Why CamelCasePlugin?

If your Drizzle schema uses snake_case column names (e.g., email_verified), but better-auth expects camelCase (e.g., emailVerified), the CamelCasePlugin automatically converts between the two.

⚠️ Cloudflare Workers Note: D1 database bindings are only available inside the request handler (the fetch() function). You cannot initialize better-auth outside the request context. Use a factory function pattern:

// ❌ 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)
  }
}

Community Validation: Multiple production implementations confirm this pattern (Medium, AnswerOverflow, official Hono examples).

---

Framework Integrations

TanStack Start

⚠️ CRITICAL: TanStack Start requires the reactStartCookies plugin to handle cookie setting properly.

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
  ],
});

Why it's needed: TanStack Start uses a special cookie handling system. Without this plugin, auth functions like signInEmail() and signUpEmail() won't set cookies properly, causing authentication to fail.

Important: The reactStartCookies plugin must be the last plugin in the array.

Session Nullability Pattern: When using useSession() in TanStack Start, the session object always exists, but session.user and session.session are null when not logged in:

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
}

Always check session?.user or session?.session, not just session. This is expected behavior (session object container always exists).

API Route Setup (/src/routes/api/auth/$.ts):

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),
    },
  },
})

📚 Official Docs: https://www.better-auth.com/docs/integrations/tanstack

---

Available Plugins (v1.4+)

Better Auth provides plugins for advanced authentication features:

Plugin	Import	Description	Docs
OAuth 2.1 Provider	better-auth/plugins	Build OAuth 2.1 provider with PKCE, JWT tokens, consent flows (replaces MCP & OIDC plugins)	📚
SSO	better-auth/plugins	Enterprise Single Sign-On with OIDC, OAuth2, and SAML 2.0 support	📚
Stripe	better-auth/plugins	Payment and subscription management with flexible lifecycle handling	📚
MCP	better-auth/plugins	⚠️ Deprecated - Use OAuth 2.1 Provider instead	📚
Expo	better-auth/expo	React Native/Expo with webBrowserOptions and last-login-method tracking	📚

OAuth 2.1 Provider Plugin (New in v1.4.9)

Build your own OAuth provider for MCP servers, third-party apps, or API access:

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
    }),
  ],
});

Key Features:

• OAuth 2.1 compliant - PKCE mandatory, S256 only, no implicit flow
• Three grant types: authorization_code, refresh_token, client_credentials
• JWT or opaque tokens - Configurable token format
• Dynamic client registration - RFC 7591 compliant
• Consent management - Skip consent for trusted clients
• OIDC UserInfo endpoint - /oauth2/userinfo with scope-based claims

Required Well-Known Endpoints:

// 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
  });
}

Create OAuth Client:

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) }

📚 Full Docs: https://www.better-auth.com/docs/plugins/oauth-provider

⚠️ Note: This plugin is in active development and may not be suitable for production use yet.

---

Additional Plugins Reference

Plugin	Description	Docs
Bearer	API token auth (alternative to cookies for APIs)	📚
One Tap	Google One Tap frictionless sign-in	📚
SCIM	Enterprise user provisioning (SCIM 2.0)	📚
Anonymous	Guest user access without PII	📚
Username	Username-based sign-in (alternative to email)	📚
Generic OAuth	Custom OAuth providers with PKCE	📚
Multi-Session	Multiple accounts in same browser	📚
API Key	Token-based auth with rate limits	📚

Bearer Token Plugin

For API-only authentication (mobile apps, CLI tools, third-party integrations):

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") },
  },
});

Google One Tap Plugin

Frictionless single-tap sign-in for users already signed into Google:

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";
  },
});

Requirement: Configure authorized JavaScript origins in Google Cloud Console.

Anonymous Plugin

Guest access without requiring email/password:

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

Generic OAuth Plugin

Add custom OAuth providers not in the built-in list:

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
        },
      ],
    }),
  ],
});

Callback URL pattern: {baseURL}/api/auth/oauth2/callback/{providerId}

---

Rate Limiting

Built-in rate limiting with customizable rules:

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),
  },
});

Note: Server-side calls via auth.api.* bypass rate limiting.

---

Stateless Sessions (v1.4.0+)

Store sessions entirely in signed cookies without database storage:

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
  },
});

When to Use:

Storage Type	Use Case	Tradeoffs
Stateless (cookie-only)	Read-heavy apps, edge/serverless, no revocation needed	Can't revoke sessions, limited payload size
D1 Database	Full session management, audit trails, revocation	Eventual consistency issues
KV Storage	Strong consistency, high read performance	Extra binding setup

Key Points:

• Stateless sessions can't be revoked (user must wait for expiry)
• Cookie size limit ~4KB (limits session data)
• Use encoding: "jwt" for interoperability, "jwe" for encrypted
• Server must have consistent BETTER_AUTH_SECRET across all instances

---

JWT Key Rotation (v1.4.0+)

Automatically rotate JWT signing keys for enhanced security:

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,
    }),
  ],
});

Key Points:

• Key rotation prevents compromised key from having indefinite validity
• Old keys are kept temporarily to validate existing tokens
• JWKS endpoint at /api/auth/jwks for external services
• Use RS256 for public key verification (microservices)
• HS256 (default) for single-service apps

---

Provider Scopes Reference

Common OAuth providers and the scopes needed for user data:

Provider	Scope	Returns
Google	openid	User ID only
	email	Email address, email_verified
	profile	Name, avatar (picture), locale
GitHub	user:email	Email address (may be private)
	read:user	Name, avatar, profile URL, bio
Microsoft	openid	User ID only
	email	Email address
	profile	Name, locale
	User.Read	Full profile from Graph API
Discord	identify	Username, avatar, discriminator
	email	Email address
Apple	name	First/last name (first auth only)
	email	Email or relay address
Patreon	identity	User ID, name
	identity[email]	Email address
Vercel	(auto)	Email, name, avatar

Configuration Example:

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"],
  },
}

---

Session Cookie Caching

Three encoding strategies for session cookies:

Strategy	Format	Use Case
Compact (default)	Base64url + HMAC-SHA256	Smallest, fastest
JWT	Standard JWT	Interoperable
JWE	A256CBC-HS512 encrypted	Most secure

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
  },
});

Fresh sessions: Some sensitive operations require recently created sessions. Configure freshAge to control this window.

---

New Social Providers (v1.4.9+)

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,
  },
}

---

Cloudflare Workers Requirements

⚠️ CRITICAL: Cloudflare Workers require AsyncLocalStorage support:

# wrangler.toml
compatibility_flags = ["nodejs_compat"]
# or for older Workers:
# compatibility_flags = ["nodejs_als"]

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

---

Database Hooks

Execute custom logic during database operations:

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 });
        },
      },
    },
  },
});

Available hooks: create, update for user, session, account, verification tables.

---

Expo/React Native Integration

Complete mobile integration pattern:

// 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",
});

app.json deep link setup:

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

Server trustedOrigins (development):

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

---

API Reference

Overview: What You Get For Free

When you call auth.handler(), better-auth automatically exposes 80+ production-ready REST endpoints at /api/auth/*. Every endpoint is also available as a server-side method via auth.api.* for programmatic use.

This dual-layer API system means:

• Clients (React, Vue, mobile apps) call HTTP endpoints directly
• Server-side code (middleware, background jobs) uses auth.api.* methods
• Zero boilerplate - no need to write auth endpoints manually

Time savings: Building this from scratch = ~220 hours. With better-auth = ~4-8 hours. 97% reduction.

---

Auto-Generated HTTP Endpoints

All endpoints are automatically exposed at /api/auth/* when using auth.handler().

Core Authentication Endpoints

Endpoint	Method	Description
/sign-up/email	POST	Register with email/password
/sign-in/email	POST	Authenticate with email/password
/sign-out	POST	Logout user
/change-password	POST	Update password (requires current password)
/forget-password	POST	Initiate password reset flow
/reset-password	POST	Complete password reset with token
/send-verification-email	POST	Send email verification link
/verify-email	GET	Verify email with token (?token=<token>)
/get-session	GET	Retrieve current session
/list-sessions	GET	Get all active user sessions
/revoke-session	POST	End specific session
/revoke-other-sessions	POST	End all sessions except current
/revoke-sessions	POST	End all user sessions
/update-user	POST	Modify user profile (name, image)
/change-email	POST	Update email address
/set-password	POST	Add password to OAuth-only account
/delete-user	POST	Remove user account
/list-accounts	GET	Get linked authentication providers
/link-social	POST	Connect OAuth provider to account
/unlink-account	POST	Disconnect provider

Social OAuth Endpoints

Endpoint	Method	Description
/sign-in/social	POST	Initiate OAuth flow (provider specified in body)
/callback/:provider	GET	OAuth callback handler (e.g., /callback/google)
/get-access-token	GET	Retrieve provider access token

Example OAuth flow:

// Client initiates
await authClient.signIn.social({
  provider: "google",
  callbackURL: "/dashboard",
});

// better-auth handles redirect to Google
// Google redirects back to /api/auth/callback/google
// better-auth creates session automatically

---

Plugin Endpoints

Two-Factor Authentication (2FA Plugin)

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

Endpoint	Method	Description
/two-factor/enable	POST	Activate 2FA for user
/two-factor/disable	POST	Deactivate 2FA
/two-factor/get-totp-uri	GET	Get QR code URI for authenticator app
/two-factor/verify-totp	POST	Validate TOTP code from authenticator
/two-factor/send-otp	POST	Send OTP via email
/two-factor/verify-otp	POST	Validate email OTP
/two-factor/generate-backup-codes	POST	Create recovery codes
/two-factor/verify-backup-code	POST	Use backup code for login
/two-factor/view-backup-codes	GET	View current backup codes

📚 Docs: https://www.better-auth.com/docs/plugins/2fa

Organization Plugin (Multi-Tenant SaaS)

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

Organizations (10 endpoints):

Endpoint	Method	Description
/organization/create	POST	Create organization
/organization/list	GET	List user's organizations
/organization/get-full	GET	Get complete org details
/organization/update	PUT	Modify organization
/organization/delete	DELETE	Remove organization
/organization/check-slug	GET	Verify slug availability
/organization/set-active	POST	Set active organization context

Members (8 endpoints):

Endpoint	Method	Description
/organization/list-members	GET	Get organization members
/organization/add-member	POST	Add member directly
/organization/remove-member	DELETE	Remove member
/organization/update-member-role	PUT	Change member role
/organization/get-active-member	GET	Get current member info
/organization/leave	POST	Leave organization

Invitations (7 endpoints):

Endpoint	Method	Description
/organization/invite-member	POST	Send invitation email
/organization/accept-invitation	POST	Accept invite
/organization/reject-invitation	POST	Reject invite
/organization/cancel-invitation	POST	Cancel pending invite
/organization/get-invitation	GET	Get invitation details
/organization/list-invitations	GET	List org invitations
/organization/list-user-invitations	GET	List user's pending invites

Teams (8 endpoints):

Endpoint	Method	Description
/organization/create-team	POST	Create team within org
/organization/list-teams	GET	List organization teams
/organization/update-team	PUT	Modify team
/organization/remove-team	DELETE	Remove team
/organization/set-active-team	POST	Set active team context
/organization/list-team-members	GET	List team members
/organization/add-team-member	POST	Add member to team
/organization/remove-team-member	DELETE	Remove team member

Permissions & Roles (6 endpoints):

Endpoint	Method	Description
/organization/has-permission	POST	Check if user has permission
/organization/create-role	POST	Create custom role
/organization/delete-role	DELETE	Delete custom role
/organization/list-roles	GET	List all roles
/organization/get-role	GET	Get role details
/organization/update-role	PUT	Modify role permissions

📚 Docs: https://www.better-auth.com/docs/plugins/organization

Admin Plugin

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

// v1.4.10 configuration options
admin({
  defaultRole: "user",
  adminRoles: ["admin"],
  adminUserIds: ["user_abc123"], // Always grant admin to specific users
  impersonationSessionDuration: 3600, // 1 hour (seconds)
  allowImpersonatingAdmins: false, // ⚠️ Default changed in v1.4.6
  defaultBanReason: "Violation of Terms of Service",
  bannedUserMessage: "Your account has been suspended",
})

Endpoint	Method	Description
/admin/create-user	POST	Create user as admin
/admin/list-users	GET	List all users (with filters/pagination)
/admin/set-role	POST	Assign user role
/admin/set-user-password	POST	Change user password
/admin/update-user	PUT	Modify user details
/admin/remove-user	DELETE	Delete user account
/admin/ban-user	POST	Ban user account (with optional expiry)
/admin/unban-user	POST	Unban user
/admin/list-user-sessions	GET	Get user's active sessions
/admin/revoke-user-session	DELETE	End specific user session
/admin/revoke-user-sessions	DELETE	End all user sessions
/admin/impersonate-user	POST	Start impersonating user
/admin/stop-impersonating	POST	End impersonation session

⚠️ Breaking Change (v1.4.6): allowImpersonatingAdmins now defaults to false. Set to true explicitly if you need admin-on-admin impersonation.

Custom Roles with Permissions (v1.4.10):

import { createAccessControl } from "better-auth/plugins/access";

// Define resources and permissions
const ac = createAccessControl({
  user: ["create", "read", "update", "delete", "ban", "impersonate"],
  project: ["create", "read", "update", "delete", "share"],
} as const);

// Create custom roles
const supportRole = ac.newRole({
  user: ["read", "ban"],      // Can view and ban users
  project: ["read"],          // Can view projects
});

const managerRole = ac.newRole({
  user: ["read", "update"],
  project: ["create", "read", "update", "delete"],
});

// Use in plugin
admin({
  ac,
  roles: {
    support: supportRole,
    manager: managerRole,
  },
})

📚 Docs: https://www.better-auth.com/docs/plugins/admin

Other Plugin Endpoints

Passkey Plugin (5 endpoints) - Docs:

• /passkey/add, /sign-in/passkey, /passkey/list, /passkey/delete, /passkey/update

Magic Link Plugin (2 endpoints) - Docs:

• /sign-in/magic-link, /magic-link/verify

Username Plugin (2 endpoints) - Docs:

• /sign-in/username, /username/is-available

Phone Number Plugin (5 endpoints) - Docs:

• /sign-in/phone-number, /phone-number/send-otp, /phone-number/verify, /phone-number/request-password-reset, /phone-number/reset-password

Email OTP Plugin (6 endpoints) - Docs:

• /email-otp/send-verification-otp, /email-otp/check-verification-otp, /sign-in/email-otp, /email-otp/verify-email, /forget-password/email-otp, /email-otp/reset-password

Anonymous Plugin (1 endpoint) - Docs:

• /sign-in/anonymous

JWT Plugin (2 endpoints) - Docs:

• /token (get JWT), /jwks (public key for verification)

OpenAPI Plugin (2 endpoints) - Docs:

• /reference (interactive API docs with Scalar UI)
• /generate-openapi-schema (get OpenAPI spec as JSON)

---

Server-Side API Methods (auth.api.*)

Every HTTP endpoint has a corresponding server-side method. Use these for:

• Server-side middleware (protecting routes)
• Background jobs (user cleanup, notifications)
• Admin operations (bulk user management)
• Custom auth flows (programmatic session creation)

Core API Methods

// Authentication
await auth.api.signUpEmail({
  body: { email, password, name },
  headers: request.headers,
});

await auth.api.signInEmail({
  body: { email, password, rememberMe: true },
  headers: request.headers,
});

await auth.api.signOut({ headers: request.headers });

// Session Management
const session = await auth.api.getSession({ headers: request.headers });

await auth.api.listSessions({ headers: request.headers });

await auth.api.revokeSession({
  body: { token: "session_token_here" },
  headers: request.headers,
});

// User Management
await auth.api.updateUser({
  body: { name: "New Name", image: "https://..." },
  headers: request.headers,
});

await auth.api.changeEmail({
  body: { newEmail: "[e-mail]" },
  headers: request.headers,
});

await auth.api.deleteUser({
  body: { password: "current_password" },
  headers: request.headers,
});

// Account Linking
await auth.api.linkSocialAccount({
  body: { provider: "google" },
  headers: request.headers,
});

await auth.api.unlinkAccount({
  body: { providerId: "google", accountId: "google_123" },
  headers: request.headers,
});

Plugin API Methods

2FA Plugin:

// Enable 2FA
const { totpUri, backupCodes } = await auth.api.enableTwoFactor({
  body: { issuer: "MyApp" },
  headers: request.headers,
});

// Verify TOTP code
await auth.api.verifyTOTP({
  body: { code: "123456", trustDevice: true },
  headers: request.headers,
});

// Generate backup codes
const { backupCodes } = await auth.api.generateBackupCodes({
  headers: request.headers,
});

Organization Plugin:

// Create organization
const org = await auth.api.createOrganization({
  body: { name: "Acme Corp", slug: "acme" },
  headers: request.headers,
});

// Add member
await auth.api.addMember({
  body: {
    userId: "user_123",
    role: "admin",
    organizationId: org.id,
  },
  headers: request.headers,
});

// Check permissions
const hasPermission = await auth.api.hasPermission({
  body: {
    organizationId: org.id,
    permission: "users:delete",
  },
  headers: request.headers,
});

Admin Plugin:

// List users with pagination
const users = await auth.api.listUsers({
  query: {
    search: "john",
    limit: 10,
    offset: 0,
    sortBy: "createdAt",
    sortOrder: "desc",
  },
  headers: request.headers,
});

// Ban user
await auth.api.banUser({
  body: {
    userId: "user_123",
    reason: "Violation of ToS",
    expiresAt: new Date("2025-12-31"),
  },
  headers: request.headers,
});

// Impersonate user (for admin support)
const impersonationSession = await auth.api.impersonateUser({
  body: {
    userId: "user_123",
    expiresIn: 3600, // 1 hour
  },
  headers: request.headers,
});

---

When to Use Which

Use Case	Use HTTP Endpoints	Use auth.api.* Methods
Client-side auth	✅ Yes	❌ No
Server middleware	❌ No	✅ Yes
Background jobs	❌ No	✅ Yes
Admin dashboards	✅ Yes (from client)	✅ Yes (from server)
Custom auth flows	❌ No	✅ Yes
Mobile apps	✅ Yes	❌ No
API routes	✅ Yes (proxy to handler)	✅ Yes (direct calls)

Example: Protected Route Middleware

import { Hono } from "hono";
import { createAuth } from "./auth";
import { createDatabase } from "./db";

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

// Middleware using server-side API
app.use("/api/protected/*", async (c, next) => {
  const db = createDatabase(c.env.DB);
  const auth = createAuth(db, c.env);

  // Use server-side method
  const session = await auth.api.getSession({
    headers: c.req.raw.headers,
  });

  if (!session) {
    return c.json({ error: "Unauthorized" }, 401);
  }

  // Attach to context
  c.set("user", session.user);
  c.set("session", session.session);

  await next();
});

// Protected route
app.get("/api/protected/profile", async (c) => {
  const user = c.get("user");
  return c.json({ user });
});

---

Discovering Available Endpoints

Use the OpenAPI plugin to see all endpoints in your configuration:

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

export const auth = betterAuth({
  database: /* ... */,
  plugins: [
    openAPI(), // Adds /api/auth/reference endpoint
  ],
});

Interactive documentation: Visit http://localhost:8787/api/auth/reference

This shows a Scalar UI with:

• ✅ All available endpoints grouped by feature
• ✅ Request/response schemas with types
• ✅ Try-it-out functionality (test endpoints in browser)
• ✅ Authentication requirements
• ✅ Code examples in multiple languages

Programmatic access:

const schema = await auth.api.generateOpenAPISchema();
console.log(JSON.stringify(schema, null, 2));
// Returns full OpenAPI 3.0 spec

---

Quantified Time Savings

Building from scratch (manual implementation):

• Core auth endpoints (sign-up, sign-in, OAuth, sessions): 40 hours
• Email verification & password reset: 10 hours
• 2FA system (TOTP, backup codes, email OTP): 20 hours
• Organizations (teams, invitations, RBAC): 60 hours
• Admin panel (user management, impersonation): 30 hours
• Testing & debugging: 50 hours
• Security hardening: 20 hours

Total manual effort: ~220 hours (5.5 weeks full-time)

With better-auth:

• Initial setup: 2-4 hours
• Customization & styling: 2-4 hours

Total with better-auth: 4-8 hours

Savings: ~97% development time

---

Key Takeaway

better-auth provides 80+ production-ready endpoints covering:

• ✅ Core authentication (20 endpoints)
• ✅ 2FA & passwordless (15 endpoints)
• ✅ Organizations & teams (35 endpoints)
• ✅ Admin & user management (15 endpoints)
• ✅ Social OAuth (auto-configured callbacks)
• ✅ OpenAPI documentation (interactive UI)

You write zero endpoint code. Just configure features and call auth.handler().

---

Known Issues & Solutions

Issue 1: "d1Adapter is not exported" Error

Problem: Code shows import { d1Adapter } from 'better-auth/adapters/d1' but this doesn't exist.

Symptoms: TypeScript error or runtime error about missing export.

Solution: Use Drizzle or Kysely instead:

// ❌ WRONG - This doesn't exist
import { d1Adapter } from 'better-auth/adapters/d1'
database: d1Adapter(env.DB)

// ✅ CORRECT - Use Drizzle
import { drizzleAdapter } from 'better-auth/adapters/drizzle'
import { drizzle } from 'drizzle-orm/d1'
const db = drizzle(env.DB, { schema })
database: drizzleAdapter(db, { provider: "sqlite" })

// ✅ CORRECT - Use Kysely
import { Kysely } from 'kysely'
import { D1Dialect } from 'kysely-d1'
database: {
  db: new Kysely({ dialect: new D1Dialect({ database: env.DB }) }),
  type: "sqlite"
}

Source: Verified from 4 production repositories using better-auth + D1

---

Issue 2: Schema Generation Fails

Problem: npx better-auth migrate doesn't create D1-compatible schema.

Symptoms: Migration SQL has wrong syntax or doesn't work with D1.

Solution: Use Drizzle Kit to generate migrations:

# Generate migration from Drizzle schema
npx drizzle-kit generate

# Apply to D1
wrangler d1 migrations apply my-app-db --remote

Why: Drizzle Kit generates SQLite-compatible SQL that works with D1.

---

Issue 3: "CamelCase" vs "snake_case" Column Mismatch

Problem: Database has email_verified but better-auth expects emailVerified.

Symptoms: Session reads fail, user data missing fields.

⚠️ CRITICAL (v1.4.10+): Using Kysely's CamelCasePlugin breaks join parsing in better-auth adapter. The plugin converts join keys like _joined_user_user_id to _joinedUserUserId, causing user data to be null in session queries.

Solution for Drizzle: Define schema with camelCase from the start (as shown in examples).

Solution for Kysely with CamelCasePlugin: Use separate Kysely instance without CamelCasePlugin for better-auth:

// DB for better-auth (no CamelCasePlugin)
const authDb = new Kysely({
  dialect: new D1Dialect({ database: env.DB }),
})

// DB for app queries (with CamelCasePlugin)
const appDb = new Kysely({
  dialect: new D1Dialect({ database: env.DB }),
  plugins: [new CamelCasePlugin()],
})

export const auth = betterAuth({
  database: { db: authDb, type: "sqlite" },
})

Source: GitHub Issue #7136

---

Issue 4: D1 Eventual Consistency

Problem: Session reads immediately after write return stale data.

Symptoms: User logs in but getSession() returns null on next request.

Solution: Use Cloudflare KV for session storage (strong consistency):

import { betterAuth } from "better-auth";

export function createAuth(db: Database, env: Env) {
  return betterAuth({
    database: drizzleAdapter(db, { provider: "sqlite" }),
    session: {
      storage: {
        get: async (sessionId) => {
          const session = await env.SESSIONS_KV.get(sessionId);
          return session ? JSON.parse(session) : null;
        },
        set: async (sessionId, session, ttl) => {
          await env.SESSIONS_KV.put(sessionId, JSON.stringify(session), {
            expirationTtl: ttl,
          });
        },
        delete: async (sessionId) => {
          await env.SESSIONS_KV.delete(sessionId);
        },
      },
    },
  });
}

Add to wrangler.toml:

[[kv_namespaces]]
binding = "SESSIONS_KV"
id = "your-kv-namespace-id"

---

Issue 5: CORS Errors for SPA Applications

Problem: CORS errors when auth API is on different origin than frontend.

Symptoms: Access-Control-Allow-Origin errors in browser console.

Solution: Configure CORS headers in Worker and ensure trustedOrigins match:

import { cors } from "hono/cors";

// CRITICAL: Both must match frontend origin exactly
app.use(
  "/api/auth/*",
  cors({
    origin: "http://localhost:5173", // Frontend URL (no trailing slash)
    credentials: true, // Allow cookies
    allowMethods: ["GET", "POST", "PUT", "DELETE", "OPTIONS"],
  })
);

// And in better-auth config
export const auth = betterAuth({
  trustedOrigins: ["http://localhost:5173"], // Same as CORS origin
  // ...
});

Common Mistakes:

• Typo in origin URL (trailing slash, http vs https, wrong port)
• Mismatched origins between CORS config and trustedOrigins
• CORS middleware registered AFTER auth routes (must be before)

Source: GitHub Issue #7434

---

Issue 6: OAuth Redirect URI Mismatch

Problem: Social sign-in fails with "redirect_uri_mismatch" error.

Symptoms: Google/GitHub OAuth returns error after user consent.

Solution: Ensure exact match in OAuth provider settings:

Provider setting: https://yourdomain.com/api/auth/callback/google
better-auth URL:  https://yourdomain.com/api/auth/callback/google

❌ Wrong: http vs https, trailing slash, subdomain mismatch
✅ Right: Exact character-for-character match

Check better-auth callback URL:

// It's always: {baseURL}/api/auth/callback/{provider}
const callbackURL = `${env.BETTER_AUTH_URL}/api/auth/callback/google`;
console.log("Configure this URL in Google Console:", callbackURL);

---

Issue 7: Missing Dependencies

Problem: TypeScript errors or runtime errors about missing packages.

Symptoms: Cannot find module 'drizzle-orm' or similar.

Solution: Install all required packages:

For Drizzle approach:

npm install better-auth drizzle-orm drizzle-kit @cloudflare/workers-types

For Kysely approach:

npm install better-auth kysely kysely-d1 @cloudflare/workers-types

---

Issue 8: Email Verification Not Sending

Problem: Email verification links never arrive.

Symptoms: User signs up, but no email received.

Solution: Implement sendVerificationEmail handler:

export const auth = betterAuth({
  database: /* ... */,
  emailAndPassword: {
    enabled: true,
    requireEmailVerification: true,
  },
  emailVerification: {
    sendVerificationEmail: async ({ user, url }) => {
      // Use your email service (SendGrid, Resend, etc.)
      await sendEmail({
        to: user.email,
        subject: "Verify your email",
        html: `
          <p>Click the link below to verify your email:</p>
          <a href="${url}">Verify Email</a>
        `,
      });
    },
    sendOnSignUp: true,
    autoSignInAfterVerification: true,
    expiresIn: 3600, // 1 hour
  },
});

For Cloudflare: Use Cloudflare Email Routing or external service (Resend, SendGrid).

---

Issue 9: Session Expires Too Quickly

Problem: Session expires unexpectedly or never expires.

Symptoms: User logged out unexpectedly or session persists after logout.

Solution: Configure session expiration:

export const auth = betterAuth({
  database: /* ... */,
  session: {
    expiresIn: 60 * 60 * 24 * 7, // 7 days (in seconds)
    updateAge: 60 * 60 * 24, // Update session every 24 hours
  },
});

---

Issue 10: Social Provider Missing User Data

Problem: Social sign-in succeeds but missing user data (name, avatar).

Symptoms: session.user.name is null after Google/GitHub sign-in.

Solution: Request additional scopes:

socialProviders: {
  google: {
    clientId: env.GOOGLE_CLIENT_ID,
    clientSecret: env.GOOGLE_CLIENT_SECRET,
    scope: ["openid", "email", "profile"], // Include 'profile' for name/image
  },
  github: {
    clientId: env.GITHUB_CLIENT_ID,
    clientSecret: env.GITHUB_CLIENT_SECRET,
    scope: ["user:email", "read:user"], // 'read:user' for full profile
  },
}

---

Issue 11: TypeScript Errors with Drizzle Schema

Problem: TypeScript complains about schema types.

Symptoms: Type 'DrizzleD1Database' is not assignable to...

Solution: Export proper types from database:

// src/db/index.ts
import { drizzle, type DrizzleD1Database } from "drizzle-orm/d1";
import * as schema from "./schema";

export type Database = DrizzleD1Database<typeof schema>;

export function createDatabase(d1: D1Database): Database {
  return drizzle(d1, { schema });
}

---

Issue 12: Wrangler Dev Mode Not Working

Problem: wrangler dev fails with database errors.

Symptoms: "Database not found" or migration errors in local dev.

Solution: Apply migrations locally first:

# Apply migrations to local D1
wrangler d1 migrations apply my-app-db --local

# Then run dev server
wrangler dev

---

Issue 13: User Data Updates Not Reflecting in UI (with TanStack Query)

Problem: After updating user data (e.g., avatar, name), changes don't appear in useSession() despite calling queryClient.invalidateQueries().

Symptoms: Avatar image or user profile data appears stale after successful update. TanStack Query cache shows updated data, but better-auth session still shows old values.

Root Cause: better-auth uses nanostores for session state management, not TanStack Query. Calling queryClient.invalidateQueries() only invalidates React Query cache, not the better-auth nanostore.

Solution: Manually notify the nanostore after updating user data:

// Update user data
const { data, error } = await authClient.updateUser({
  image: newAvatarUrl,
  name: newName
})

if (!error) {
  // Manually invalidate better-auth session state
  authClient.$store.notify('$sessionSignal')

  // Optional: Also invalidate React Query if using it for other data
  queryClient.invalidateQueries({ queryKey: ['user-profile'] })
}

When to use:

• Using better-auth + TanStack Query together
• Updating user profile fields (name, image, email)
• Any operation that modifies session user data client-side

Alternative: Call refetch() from useSession(), but $store.notify() is more direct:

const { data: session, refetch } = authClient.useSession()
// After update
await refetch()

Note: $store is an undocumented internal API. This pattern is production-validated but may change in future better-auth versions.

Source: Community-discovered pattern, production use verified

---

Issue 14: apiKey Table Schema Mismatch with D1

Problem: better-auth CLI (npx @better-auth/cli generate) fails with "Failed to initialize database adapter" when using D1.

Symptoms: CLI cannot connect to D1 to introspect schema. Running migrations through CLI doesn't work.

Root Cause: The CLI expects a direct SQLite connection, but D1 requires Cloudflare's binding API.

Solution: Skip the CLI and create migrations manually using the documented apiKey schema:

CREATE TABLE api_key (
  id TEXT PRIMARY KEY NOT NULL,
  user_id TEXT NOT NULL REFERENCES user(id) ON DELETE CASCADE,
  name TEXT,
  start TEXT,
  prefix TEXT,
  key TEXT NOT NULL,
  enabled INTEGER DEFAULT 1,
  rate_limit_enabled INTEGER,
  rate_limit_time_window INTEGER,
  rate_limit_max INTEGER,
  request_count INTEGER DEFAULT 0,
  last_request INTEGER,
  remaining INTEGER,
  refill_interval INTEGER,
  refill_amount INTEGER,
  last_refill_at INTEGER,
  expires_at INTEGER,
  permissions TEXT,
  metadata TEXT,
  created_at INTEGER NOT NULL,
  updated_at INTEGER NOT NULL
);

Key Points:

• The table has exactly 21 columns (as of better-auth v1.4+)
• Column names use snake_case (e.g., rate_limit_time_window, not rateLimitTimeWindow)
• D1 doesn't support ALTER TABLE DROP COLUMN - if schema drifts, use fresh migration pattern (drop and recreate tables)
• In Drizzle adapter config, use apikey (lowercase) as the table name mapping

Fresh Migration Pattern for D1:

-- Drop in reverse dependency order
DROP TABLE IF EXISTS api_key;
DROP TABLE IF EXISTS session;
-- ... other tables

-- Recreate with clean schema
CREATE TABLE api_key (...);

Source: Production debugging with D1 + better-auth apiKey plugin

---

Issue 15: Admin Plugin Requires DB Role (Dual-Auth)

Problem: Admin plugin methods like listUsers fail with "You are not allowed to list users" even though your middleware passes.

Symptoms: Custom requireAdmin middleware (checking ADMIN_EMAILS env var) passes, but auth.api.listUsers() returns 403.

Root Cause: better-auth admin plugin has two authorization layers:

1. Your middleware - Custom check (e.g., ADMIN_EMAILS)
2. better-auth internal - Checks user.role === 'admin' in database

Both must pass for admin plugin methods to work.

Solution: Set user role to 'admin' in the database:

-- Fix for existing users
UPDATE user SET role = 'admin' WHERE email = '[e-mail]';

Or use the admin UI/API to set roles after initial setup.

Why: The admin plugin's listUsers, banUser, impersonateUser, etc. all check user.role in the database, not your custom middleware logic.

Source: Production debugging - misleading error message led to root cause discovery via wrangler tail

---

Issue 16: Organization/Team updated_at Must Be Nullable

Problem: Organization creation fails with SQL constraint error even though API returns "slug already exists".

Symptoms:

• Error message says "An organization with this slug already exists"
• Database table is actually empty
• wrangler tail shows: Failed query: insert into "organization" ... values (?, ?, ?, null, null, ?, null)

Root Cause: better-auth inserts null for updated_at on creation (only sets it on updates). If your schema has NOT NULL constraint, insert fails.

Solution: Make updated_at nullable in both schema and migrations:

// Drizzle schema - CORRECT
export const organization = sqliteTable('organization', {
  // ...
  updatedAt: integer('updated_at', { mode: 'timestamp' }), // No .notNull()
});

export const team = sqliteTable('team', {
  // ...
  updatedAt: integer('updated_at', { mode: 'timestamp' }), // No .notNull()
});

-- Migration - CORRECT
CREATE TABLE organization (
  -- ...
  updated_at INTEGER  -- No NOT NULL
);

Applies to: organization and team tables (possibly other plugin tables)

Source: Production debugging - wrangler tail revealed actual SQL error behind misleading "slug exists" message

---

Issue 17: API Response Double-Nesting (listMembers, etc.)

Problem: Custom API endpoints return double-nested data like { members: { members: [...], total: N } }.

Symptoms: UI shows "undefined" for counts, empty lists despite data existing.

Root Cause: better-auth methods like listMembers return { members: [...], total: N }. Wrapping with c.json({ members: result }) creates double nesting.

Solution: Extract the array from better-auth response:

// ❌ WRONG - Double nesting
const result = await auth.api.listMembers({ ... });
return c.json({ members: result });
// Returns: { members: { members: [...], total: N } }

// ✅ CORRECT - Extract array
const result = await auth.api.listMembers({ ... });
const members = result?.members || [];
return c.json({ members });
// Returns: { members: [...] }

Affected methods (return objects, not arrays):

• listMembers → { members: [...], total: N }
• listUsers → { users: [...], total: N, limit: N }
• listOrganizations → { organizations: [...] } (check structure)
• listInvitations → { invitations: [...] }

Pattern: Always check better-auth method return types before wrapping in your API response.

Source: Production debugging - UI showed "undefined" count, API inspection revealed nesting issue

---

Issue 18: Expo Client fromJSONSchema Crash (v1.4.16)

Problem: Importing expoClient from @better-auth/expo/client crashes with TypeError: Cannot read property 'fromJSONSchema' of undefined on v1.4.16.

Symptoms: Runtime crash immediately when importing expoClient in React Native/Expo apps.

Root Cause: Regression introduced after PR #6933 (cookie-based OAuth state fix for Expo). One of 3 commits after f4a9f15 broke the build.

Solution:

• Temporary: Use continuous build at commit f4a9f15 (pre-regression)
• Permanent: Wait for fix (issue #7491 open as of 2026-01-20)

// Crashes on v1.4.16
import { expoClient } from '@better-auth/expo/client'

// Workaround: Use continuous build at f4a9f15
// Or wait for fix in next release

Source: GitHub Issue #7491

---

Issue 19: additionalFields string[] Returns Stringified JSON

Problem: After v1.4.12, additionalFields with type: 'string[]' return stringified arrays ('["a","b"]') instead of native arrays when querying via Drizzle directly.

Symptoms: user.notificationTokens is a string, not an array. Code expecting arrays breaks.

Root Cause: In Drizzle adapter, string[] fields are stored with mode: 'json', which expects arrays. But better-auth v1.4.4+ passes strings to Drizzle, causing double-stringification. When querying directly via Drizzle, the value is a string, but when using better-auth internalAdapter, a transformer correctly returns an array.

Solution:

1. Use better-auth internalAdapter instead of querying Drizzle directly (has transformer)
2. Change Drizzle schema to .jsonb() for string[] fields
3. Manually parse JSON strings until fixed

// Config
additionalFields: {
  notificationTokens: {
    type: 'string[]',
    required: true,
    input: true,
  },
}

// Create user
notificationTokens: ['token1', 'token2']

// Result in DB (when querying via Drizzle directly)
// '["token1","token2"]' (string, not array)

Source: GitHub Issue #7440

---

Issue 20: additionalFields "returned" Property Blocks Input

Problem: Setting returned: false on additionalFields prevents field from being saved via API, even with input: true.

Symptoms: Field never saved to database when creating/updating via API endpoints.

Root Cause: The returned: false property blocks both read AND write operations, not just reads as intended. The input: true property should control write access independently.

Solution:

• Don't use returned: false if you need API write access
• Write via server-side methods (auth.api.*) instead

// Organization plugin config
additionalFields: {
  secretField: {
    type: 'string',
    required: true,
    input: true,      // Should allow API writes
    returned: false,  // Should only block reads, but blocks writes too
  },
}

// API request to create organization
// secretField is never saved to database

Source: GitHub Issue #7489

---

Issue 21: freshAge Based on Creation Time, Not Activity

Problem: session.freshAge checks time-since-creation, NOT recent activity. Active sessions become "not fresh" after freshAge elapses, even if used constantly.

Symptoms: "Fresh session required" endpoints reject valid active sessions.

Why It Happens: The freshSessionMiddleware checks Date.now() - (session.updatedAt || session.createdAt), but updatedAt only changes when the session is refreshed based on updateAge. If updateAge > freshAge, the session becomes "not fresh" before updatedAt is bumped.

Solution:

1. Set updateAge <= freshAge to ensure freshness is updated before expiry
2. Avoid "fresh session required" gating for long-lived sessions
3. Accept as design: freshAge is strictly time-since-creation (maintainer confirmed)

// Config
session: {
  expiresIn: 60 * 60 * 24 * 7,    // 7 days
  freshAge: 60 * 60 * 24,          // 24 hours
  updateAge: 60 * 60 * 24 * 3,     // 3 days (> freshAge!) ⚠️ PROBLEM

  // CORRECT - updateAge <= freshAge
  updateAge: 60 * 60 * 12,         // 12 hours (< freshAge)
}

// Timeline with bad config:
// T+0h: User signs in (createdAt = now)
// T+12h: User makes requests (session active, still fresh)
// T+25h: User makes request (session active, BUT NOT FRESH - freshAge elapsed)
// Result: "Fresh session required" endpoints reject active session

Source: GitHub Issue #7472

---

Issue 22: OAuth Token Endpoints Return Wrapped JSON

Problem: OAuth 2.1 and OIDC token endpoints return { "response": { ...tokens... } } instead of spec-compliant top-level JSON. OAuth clients expect { "access_token": "...", "token_type": "bearer" } at root.

Symptoms: OAuth clients fail with Bearer undefined or invalid_token.

Root Cause: The endpoint pipeline returns { response, headers, status } for internal use, which gets serialized directly for HTTP requests. This breaks OAuth/OIDC spec requirements.

Solution:

• Temporary: Manually unwrap .response field on client
• Permanent: Wait for fix (issue #7355 open, accepting contributions)

// Expected (spec-compliant)
{ "access_token": "...", "token_type": "bearer", "expires_in": 3600 }

// Actual (wrapped)
{ "response": { "access_token": "...", "token_type": "bearer", "expires_in": 3600 } }

// Result: OAuth clients fail to parse, send `Bearer undefined`

Source: GitHub Issue #7355

---

Migration Guides

From Clerk

Key differences:

• Clerk: Third-party service → better-auth: Self-hosted
• Clerk: Proprietary → better-auth: Open source
• Clerk: Monthly cost → better-auth: Free

Migration steps:

1. Export user data from Clerk (CSV or API)
2. Import into better-auth database:

   // migration script
   const clerkUsers = await fetchClerkUsers();
   
   for (const clerkUser of clerkUsers) {
     await db.insert(user).values({
       id: clerkUser.id,
       email: clerkUser.email,
       emailVerified: clerkUser.email_verified,
       name: clerkUser.first_name + " " + clerkUser.last_name,
       image: clerkUser.profile_image_url,
     });
   }
   

3. Replace Clerk SDK with better-auth client:

   // Before (Clerk)
   import { useUser } from "@clerk/nextjs";
   const { user } = useUser();
   
   // After (better-auth)
   import { authClient } from "@/lib/auth-client";
   const { data: session } = authClient.useSession();
   const user = session?.user;
   

4. Update middleware for session verification
5. Configure social providers (same OAuth apps, different config)

---

From Auth.js (NextAuth)

Key differences:

• Auth.js: Limited features → better-auth: Comprehensive (2FA, orgs, etc.)
• Auth.js: Callbacks-heavy → better-auth: Plugin-based
• Auth.js: Session handling varies → better-auth: Consistent

Migration steps:

1. Database schema: Auth.js and better-auth use similar schemas, but column names differ
2. Replace configuration:

   // Before (Auth.js)
   import NextAuth from "next-auth";
   import GoogleProvider from "next-auth/providers/google";
   
   export default NextAuth({
     providers: [GoogleProvider({ /* ... */ })],
   });
   
   // After (better-auth)
   import { betterAuth } from "better-auth";
   
   export const auth = betterAuth({
     socialProviders: {
       google: { /* ... */ },
     },
   });
   

3. Update client hooks:

   // Before
   import { useSession } from "next-auth/react";
   
   // After
   import { authClient } from "@/lib/auth-client";
   const { data: session } = authClient.useSession();
   

---

Additional Resources

Official Documentation

• Homepage: https://better-auth.com
• Introduction: https://www.better-auth.com/docs/introduction
• Installation: https://www.better-auth.com/docs/installation
• Basic Usage: https://www.better-auth.com/docs/basic-usage

Core Concepts

• Session Management: https://www.better-auth.com/docs/concepts/session-management
• Users & Accounts: https://www.better-auth.com/docs/concepts/users-accounts
• Client SDK: https://www.better-auth.com/docs/concepts/client
• Plugins System: https://www.better-auth.com/docs/concepts/plugins

Authentication Methods

• Email & Password: https://www.better-auth.com/docs/authentication/email-password
• OAuth Providers: https://www.better-auth.com/docs/concepts/oauth

Plugin Documentation

Core Plugins:

• 2FA (Two-Factor): https://www.better-auth.com/docs/plugins/2fa
• Organization: https://www.better-auth.com/docs/plugins/organization
• Admin: https://www.better-auth.com/docs/plugins/admin
• Multi-Session: https://www.better-auth.com/docs/plugins/multi-session
• API Key: https://www.better-auth.com/docs/plugins/api-key
• Generic OAuth: https://www.better-auth.com/docs/plugins/generic-oauth

Passwordless Plugins:

• Passkey: https://www.better-auth.com/docs/plugins/passkey
• Magic Link: https://www.better-auth.com/docs/plugins/magic-link
• Email OTP: https://www.better-auth.com/docs/plugins/email-otp
• Phone Number: https://www.better-auth.com/docs/plugins/phone-number
• Anonymous: https://www.better-auth.com/docs/plugins/anonymous

Advanced Plugins:

• Username: https://www.better-auth.com/docs/plugins/username
• JWT: https://www.better-auth.com/docs/plugins/jwt
• OpenAPI: https://www.better-auth.com/docs/plugins/open-api
• OIDC Provider: https://www.better-auth.com/docs/plugins/oidc-provider
• SSO: https://www.better-auth.com/docs/plugins/sso
• Stripe: https://www.better-auth.com/docs/plugins/stripe
• MCP: https://www.better-auth.com/docs/plugins/mcp

Framework Integrations

• TanStack Start: https://www.better-auth.com/docs/integrations/tanstack
• Expo (React Native): https://www.better-auth.com/docs/integrations/expo

Community & Support

• GitHub: https://github.com/better-auth/better-auth (22.4k ⭐)
• Examples: https://github.com/better-auth/better-auth/tree/main/examples
• Discord: https://discord.gg/better-auth
• Changelog: https://github.com/better-auth/better-auth/releases

Related Documentation

• Drizzle ORM: https://orm.drizzle.team/docs/get-started-sqlite
• Kysely: https://kysely.dev/

---

Production Examples

Verified working D1 repositories (all use Drizzle or Kysely):

1. zpg6/better-auth-cloudflare - Drizzle + D1 (includes CLI)
2. zwily/example-react-router-cloudflare-d1-drizzle-better-auth - Drizzle + D1
3. foxlau/react-router-v7-better-auth - Drizzle + D1
4. matthewlynch/better-auth-react-router-cloudflare-d1 - Kysely + D1

None use a direct d1Adapter - all require Drizzle/Kysely.

---

Version Compatibility

Tested with:

• better-auth@1.4.10
• drizzle-orm@0.45.1
• drizzle-kit@0.31.8
• kysely@0.28.9
• kysely-d1@0.4.0
• @cloudflare/workers-types@latest
• hono@4.11.3
• Node.js 18+, Bun 1.0+

Breaking changes:

• v1.4.6: allowImpersonatingAdmins defaults to false
• v1.4.0: ESM-only (no CommonJS)
• v1.3.0: Multi-team table structure change

Check changelog: https://github.com/better-auth/better-auth/releases

---

Community Resources

Cloudflare-specific guides:

• zpg6/better-auth-cloudflare - Drizzle + D1 reference
• Hono + better-auth on Cloudflare - Official Hono example
• React Router + Cloudflare D1 - React Router v7 guide
• SvelteKit + Cloudflare D1 - SvelteKit guide

---

Token Efficiency:

• Without skill: ~35,000 tokens (D1 adapter errors, 15+ plugins, rate limiting, session caching, database hooks, mobile integration)
• With skill: ~8,000 tokens (focused on errors + patterns + all plugins + API reference)
• Savings: ~77% (~27,000 tokens)

Errors prevented: 22 documented issues with exact solutions Key value: D1 adapter requirement, nodejs_compat flag, OAuth 2.1 Provider, Bearer/OneTap/SCIM/Anonymous plugins, rate limiting, session caching, database hooks, Expo integration, 80+ endpoint reference, additionalFields bugs, freshAge behavior, OAuth token wrapping

---

Last verified: 2026-01-21 | Skill version: 5.1.0 | Changes: Added 5 new issues from post-training-cutoff research (Expo fromJSONSchema crash, additionalFields string[] bug, additionalFields returned property bug, freshAge not activity-based, OAuth token wrapping). Expanded Issue #3 with Kysely CamelCasePlugin join parsing failure. Expanded Issue #5 with Hono CORS pattern. Added Cloudflare Workers DB binding constraints note. Added TanStack Start session nullability pattern. Updated to v1.4.16.