SKILL.md

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

/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: "newemail@example.com" },

  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:

Your middleware - Custom check (e.g., ADMIN_EMAILS)

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 = 'admin@example.com';

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:

**Use better-auth internalAdapter** instead of querying Drizzle directly (has transformer)

Change Drizzle schema to .jsonb() for string[] fields

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:

**Set updateAge <= freshAge** to ensure freshness is updated before expiry

Avoid "fresh session required" gating for long-lived sessions

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:

Export user data from Clerk (CSV or API)

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,

  });

}

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;

Update middleware for session verification

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:

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

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: { /* ... */ },

  },

});

Update client hooks:

// Before

import { useSession } from "next-auth/react";

// After

import { authClient } from "@/lib/auth-client";

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

Additional Resources

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

Production Examples

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

zpg6/better-auth-cloudflare - Drizzle + D1 (includes CLI)

zwily/example-react-router-cloudflare-d1-drizzle-better-auth - Drizzle + D1

foxlau/react-router-v7-better-auth - Drizzle + D1

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.

better-auth

SKILL.md

better-auth - D1 Adapter &#x26; Error Prevention Guide

⚠️ CRITICAL: D1 Adapter Requirement

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

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

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

Alternative: Kysely Adapter Pattern

Framework Integrations

TanStack Start

Available Plugins (v1.4+)

OAuth 2.1 Provider Plugin (New in v1.4.9)

Additional Plugins Reference

Rate Limiting

Stateless Sessions (v1.4.0+)

JWT Key Rotation (v1.4.0+)

Provider Scopes Reference

Session Cookie Caching

New Social Providers (v1.4.9+)

Cloudflare Workers Requirements

Database Hooks

Expo/React Native Integration

API Reference

Overview: What You Get For Free

Auto-Generated HTTP Endpoints

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

When to Use Which

Discovering Available Endpoints

Quantified Time Savings

Key Takeaway

Known Issues &#x26; Solutions

Issue 1: "d1Adapter is not exported" Error

Issue 2: Schema Generation Fails

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

Issue 4: D1 Eventual Consistency

Issue 5: CORS Errors for SPA Applications

Issue 6: OAuth Redirect URI Mismatch

Issue 7: Missing Dependencies

Issue 8: Email Verification Not Sending

Issue 9: Session Expires Too Quickly

Issue 10: Social Provider Missing User Data

Issue 11: TypeScript Errors with Drizzle Schema

Issue 12: Wrangler Dev Mode Not Working

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

Issue 14: apiKey Table Schema Mismatch with D1

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

Issue 16: Organization/Team updated_at Must Be Nullable

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

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

Issue 19: additionalFields string[] Returns Stringified JSON

Issue 20: additionalFields "returned" Property Blocks Input

Issue 21: freshAge Based on Creation Time, Not Activity

Issue 22: OAuth Token Endpoints Return Wrapped JSON

Migration Guides

From Clerk

From Auth.js (NextAuth)

Additional Resources

Official Documentation

Core Concepts

Authentication Methods

Plugin Documentation

Framework Integrations

Community &#x26; Support

Related Documentation

Production Examples

Version Compatibility

Community Resources

Let your agent run on any real-world website

Related skills

Stop writing automation&scrapers

better-auth - D1 Adapter & Error Prevention Guide

Known Issues & Solutions

Community & Support