Better Auth Integrations

Better Auth Integrations

Goals

• Mount the Better Auth handler at /api/auth/* (or a custom base path).
• Use framework helpers where available.
• Ensure cookies and headers flow correctly in SSR and server actions.

Quick start

1. Create an auth instance (see better-auth-core). 2. Add a catch-all route for /api/auth/*. 3. Use a framework helper (or auth.handler) to return a Response.

Next.js App Router

import { auth } from "@/lib/auth";
import { toNextJsHandler } from "better-auth/next-js";

export const { GET, POST } = toNextJsHandler(auth);

Next.js Pages Router

import { auth } from "@/lib/auth";
import { toNodeHandler } from "better-auth/node";

export const config = { api: { bodyParser: false } };
export default toNodeHandler(auth.handler);

Cookie handling in Next.js server actions

Use the nextCookies plugin so server actions set cookies correctly.

import { betterAuth } from "better-auth";
import { nextCookies } from "better-auth/next-js";

export const auth = betterAuth({
  // ...config
  plugins: [nextCookies()],
});

Guardrails

• Keep the base path consistent between server and client.
• Prefer framework helpers when available.
• Avoid running custom body parsers before the auth handler.

References

• toolchains/platforms/auth/better-auth/better-auth-integrations/references/nextjs.md
• toolchains/platforms/auth/better-auth/better-auth-integrations/references/frameworks.md

Framework handler recipes

SvelteKit

import { auth } from "$lib/auth";
import { svelteKitHandler } from "better-auth/svelte-kit";
import { building } from "$app/environment";

export async function handle({ event, resolve }) {
  return svelteKitHandler({ event, resolve, auth, building });
}

Remix

import { auth } from "~/lib/auth.server";
import type { LoaderFunctionArgs, ActionFunctionArgs } from "@remix-run/node";

export async function loader({ request }: LoaderFunctionArgs) {
  return auth.handler(request);
}

export async function action({ request }: ActionFunctionArgs) {
  return auth.handler(request);
}

Express

import express from "express";
import { toNodeHandler } from "better-auth/node";
import { auth } from "./auth";

const app = express();
app.all("/api/auth/*", toNodeHandler(auth));
app.use(express.json());

Hono

import { Hono } from "hono";
import { auth } from "./auth";

const app = new Hono();
app.on(["POST", "GET"], "/api/auth/*", (c) => auth.handler(c.req.raw));

Cloudflare Workers

import { auth } from "./auth";

export default {
  async fetch(request: Request) {
    const url = new URL(request.url);
    if (url.pathname.startsWith("/api/auth")) {
      return auth.handler(request);
    }
    return new Response("Not found", { status: 404 });
  },
};

Next.js integration details

API route handler

App Router:

import { auth } from "@/lib/auth";
import { toNextJsHandler } from "better-auth/next-js";

export const { GET, POST } = toNextJsHandler(auth);

Pages Router:

import { auth } from "@/lib/auth";
import { toNodeHandler } from "better-auth/node";

export const config = { api: { bodyParser: false } };
export default toNodeHandler(auth.handler);

Server actions and RSC

Use auth.api with headers() to access the session.

import { auth } from "@/lib/auth";
import { headers } from "next/headers";

export async function ServerComponent() {
  const session = await auth.api.getSession({
    headers: await headers(),
  });

  if (!session) return <div>Not authenticated</div>;
  return <div>Welcome {session.user.name}</div>;
}

Cookie handling in server actions

Add nextCookies as the last plugin so server actions set cookies:

import { betterAuth } from "better-auth";
import { nextCookies } from "better-auth/next-js";

export const auth = betterAuth({
  plugins: [nextCookies()],
});

Middleware / proxy

For Next.js 16+ proxy, avoid full DB checks in edge paths unless you opt into Node runtime.

Cookie-only check:

import { NextResponse } from "next/server";
import { getSessionCookie } from "better-auth/cookies";

export async function proxy(request: Request) {
  const sessionCookie = getSessionCookie(request);
  if (!sessionCookie) {
    return NextResponse.redirect(new URL("/", request.url));
  }
  return NextResponse.next();
}