Better Auth Core (TypeScript)

Goals

• Set up a Better Auth instance with environment variables and data layer wiring.
• Wire server handlers and a client instance.
• Use sessions and server-side API methods safely.
• Keep data-layer choices pluggable (drivers or adapters).

Quick start

1. Install

   better-auth

   .
2. Set

   BETTER_AUTH_SECRET

   (32+ chars) and

   BETTER_AUTH_URL

   .
3. Create

   auth.ts

   and export

   auth

   .
4. Provide

   database

   (driver or adapter) or omit for stateless sessions.
5. Mount a handler (

   auth.handler

   or a framework helper).
6. Create a client with

   createAuthClient

   .

import { betterAuth } from "better-auth";

export const auth = betterAuth({
  database: myDatabaseOrAdapter, // driver or adapter; omit for stateless mode
  emailAndPassword: { enabled: true },
  socialProviders: {
    github: {
      clientId: process.env.GITHUB_CLIENT_ID as string,
      clientSecret: process.env.GITHUB_CLIENT_SECRET as string,
    },
  },
});

Core setup checklist

• Export the instance as

  auth

  (or default export) so helpers find it.
• Keep

  BETTER_AUTH_URL

  in sync with the public base URL.
• Pass the full base URL to the client if you change the

  /api/auth

  base path.
• Add database migrations before enabling plugins that require tables.

Server API usage

• Call server endpoints via

  auth.api.*

  with

  { body, headers, query }

  .
• Use

  asResponse: true

  if you need a

  Response

  object.
• Use

  returnHeaders: true

  to access

  Set-Cookie

  headers.

import { auth } from "./auth";

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

const response = await auth.api.signInEmail({
  body: { email, password },
  asResponse: true,
});

Session access

• Client:

  authClient.useSession()

  or

  authClient.getSession()

  .
• Server:

  auth.api.getSession({ headers })

  .

TypeScript tips

• Infer types with

  auth.$Infer

  and

  authClient.$Infer

  .
• Use

  inferAdditionalFields

  on the client when you extend the user schema.

References

• toolchains/platforms/auth/better-auth/better-auth-core/references/setup-database.md

• toolchains/platforms/auth/better-auth/better-auth-core/references/client-server.md

• toolchains/platforms/auth/better-auth/better-auth-core/references/typescript.md