better-auth-best-practices

SKILL.md

Better Auth Integration Guide

Always consult better-auth.com/docs for code examples and latest API.

Setup Workflow

Install: npm install better-auth

Set env vars: BETTER_AUTH_SECRET and BETTER_AUTH_URL

Create auth.ts with database + config

Create route handler for your framework

Run npx @better-auth/cli@latest migrate

Verify: call GET /api/auth/ok — should return { status: "ok" }

Quick Reference
Environment Variables

BETTER_AUTH_SECRET - Encryption secret (min 32 chars). Generate: openssl rand -base64 32

BETTER_AUTH_URL - Base URL (e.g., https://example.com)

Only define baseURL/secret in config if env vars are NOT set.

File Location

CLI looks for auth.ts in: ./, ./lib, ./utils, or under ./src. Use --config for custom path.

CLI Commands

npx @better-auth/cli@latest migrate - Apply schema (built-in adapter)

npx @better-auth/cli@latest generate - Generate schema for Prisma/Drizzle

npx @better-auth/cli mcp --cursor - Add MCP to AI tools

Re-run after adding/changing plugins.

Core Config Options

Option
Notes

appName
Optional display name

baseURL
Only if BETTER_AUTH_URL not set

basePath
Default /api/auth. Set / for root.

secret
Only if BETTER_AUTH_SECRET not set

database
Required for most features. See adapters docs.

secondaryStorage
Redis/KV for sessions & rate limits

emailAndPassword
{ enabled: true } to activate

socialProviders
{ google: { clientId, clientSecret }, ... }

plugins
Array of plugins

trustedOrigins
CSRF whitelist

Database

Direct connections: Pass pg.Pool, mysql2 pool, better-sqlite3, or bun:sqlite instance.

ORM adapters: Import from better-auth/adapters/drizzle, better-auth/adapters/prisma, better-auth/adapters/mongodb.

Critical: Better Auth uses adapter model names, NOT underlying table names. If Prisma model is User mapping to table users, use modelName: "user" (Prisma reference), not "users".

Session Management

Storage priority:

If secondaryStorage defined → sessions go there (not DB)

Set session.storeSessionInDatabase: true to also persist to DB

No database + cookieCache → fully stateless mode

Cookie cache strategies:

compact (default) - Base64url + HMAC. Smallest.

jwt - Standard JWT. Readable but signed.

jwe - Encrypted. Maximum security.

Key options: session.expiresIn (default 7 days), session.updateAge (refresh interval), session.cookieCache.maxAge, session.cookieCache.version (change to invalidate all sessions).

User & Account Config

User: user.modelName, user.fields (column mapping), user.additionalFields, user.changeEmail.enabled (disabled by default), user.deleteUser.enabled (disabled by default).

Account: account.modelName, account.accountLinking.enabled, account.storeAccountCookie (for stateless OAuth).

Required for registration: email and name fields.

Email Flows

emailVerification.sendVerificationEmail - Must be defined for verification to work

emailVerification.sendOnSignUp / sendOnSignIn - Auto-send triggers

emailAndPassword.sendResetPassword - Password reset email handler

Security

In advanced:

useSecureCookies - Force HTTPS cookies

disableCSRFCheck - ⚠️ Security risk

disableOriginCheck - ⚠️ Security risk

crossSubDomainCookies.enabled - Share cookies across subdomains

ipAddress.ipAddressHeaders - Custom IP headers for proxies

database.generateId - Custom ID generation or "serial"/"uuid"/false

Rate limiting: rateLimit.enabled, rateLimit.window, rateLimit.max, rateLimit.storage ("memory" | "database" | "secondary-storage").

Hooks

Endpoint hooks: hooks.before / hooks.after - Array of { matcher, handler }. Use createAuthMiddleware. Access ctx.path, ctx.context.returned (after), ctx.context.session.

Database hooks: databaseHooks.user.create.before/after, same for session, account. Useful for adding default values or post-creation actions.

Hook context (ctx.context): session, secret, authCookies, password.hash()/verify(), adapter, internalAdapter, generateId(), tables, baseURL.

Plugins

Import from dedicated paths for tree-shaking:

import { twoFactor } from "better-auth/plugins/two-factor"

NOT from "better-auth/plugins".

Popular plugins: twoFactor, organization, passkey, magicLink, emailOtp, username, phoneNumber, admin, apiKey, bearer, jwt, multiSession, sso, oauthProvider, oidcProvider, openAPI, genericOAuth.

Client plugins go in createAuthClient({ plugins: [...] }).

Client

Import from: better-auth/client (vanilla), better-auth/react, better-auth/vue, better-auth/svelte, better-auth/solid.

Key methods: signUp.email(), signIn.email(), signIn.social(), signOut(), useSession(), getSession(), revokeSession(), revokeSessions().

Type Safety

Infer types: typeof auth.$Infer.Session, typeof auth.$Infer.Session.user.

For separate client/server projects: createAuthClient<typeof auth>().

Common Gotchas

Model vs table name - Config uses ORM model name, not DB table name

Plugin schema - Re-run CLI after adding plugins

Secondary storage - Sessions go there by default, not DB

Cookie cache - Custom session fields NOT cached, always re-fetched

Stateless mode - No DB = session in cookie only, logout on cache expiry

Change email flow - Sends to current email first, then new email

Resources

Docs

Options Reference

LLMs.txt

GitHub

Init Options Source