better-auth-core_skill

Overview

This skill provides a core setup for Better Auth in TypeScript applications. It guides creating and exporting a configured Better Auth instance, wiring database drivers or adapters, and creating client and server integrations. The goal is to make sessions, server-side auth APIs, and provider wiring safe and pluggable.

How this skill works

You create and export a configured auth instance (commonly named auth) with options for database, email/password, and social providers. The skill shows how to mount the server handler, call server APIs via auth.api.*, and create client instances with createAuthClient. It also explains session access patterns for client and server, and TypeScript helpers for inferring schemas and additional fields.

When to use it

• Setting up authentication for a new TypeScript web app.
• Wiring database drivers or adapters for stateful sessions.
• Mounting auth handlers in server frameworks or custom routes.
• Calling server-side auth APIs (sign-in, sign-out, getSession) from server code.
• Creating a client-side auth instance and accessing sessions from the UI.

Best practices

• Export the auth instance as auth (or default) so helpers and framework adapters can discover it.
• Keep BETTER_AUTH_URL set to the public base URL and match any deployed base path changes.
• Use a 32+ character BETTER_AUTH_SECRET and manage it via environment variables.
• Provide database migrations before enabling plugins that require tables; leave database undefined for stateless sessions.
• Use auth.api.* with asResponse or returnHeaders when you need Response objects or Set-Cookie headers.

Example use cases

• Create auth.ts exporting auth configured with email/password and GitHub social provider.
• Mount auth.handler (or framework helper) at /api/auth to serve all auth endpoints.
• Server-side session retrieval: const session = await auth.api.getSession({ headers }).
• Client-side flow: createAuthClient({ url: process.env.BETTER_AUTH_URL }) and call authClient.useSession().
• Call auth.api.signInEmail with { body, asResponse:true } to return the framework Response object for direct proxying.