Next.js Adapter

Overview

The Next.js adapter enables seamless integration between Autumn and Next.js applications using the App Router. It provides a clean API for handling Autumn requests in your Next.js route handlers.

Installation

Install the Autumn JS SDK which includes the Next.js adapter:

npm install autumn-js

Quick Start

Create a catch-all route handler in your Next.js app:

app/api/autumn/[...autumn]/route.ts

import { nextAutumnHandler } from "autumn-js/adapters";
import { auth } from "@/lib/auth";

const handler = nextAutumnHandler({
  identify: async (request) => {
    // Get the authenticated user
    const session = await auth();
    
    if (!session?.user) return null;
    
    return {
      customerId: session.user.id,
      customerData: {
        name: session.user.name,
        email: session.user.email,
      },
    };
  },
  secretKey: process.env.AUTUMN_SECRET_KEY,
});

export const { GET, POST, DELETE } = handler;

Configuration

The nextAutumnHandler accepts the following options:

Options

identify

(request: Request) => AuthResult

required

Function to identify the customer from the Next.js request. Return null for unauthenticated requests.Returns: { customerId: string; customerData?: { name?: string; email?: string; ... } } or null

secretKey

string

default:"process.env.AUTUMN_SECRET_KEY"

Your Autumn API secret key. Defaults to the AUTUMN_SECRET_KEY environment variable.

autumnURL

string

default:"https://api.useautumn.com/v1"

The Autumn API base URL. Only change this if you’re self-hosting Autumn.

pathPrefix

string

default:"/api/autumn"

The path prefix for all Autumn routes. Should match your route file location.

Route Handler Structure

The adapter returns an object with HTTP method handlers that you can export:

const handler = nextAutumnHandler({ /* options */ });

// Export the methods you need
export const { GET, POST, DELETE } = handler;

Supported methods:

GET - For read operations
POST - For create/update operations
DELETE - For delete operations

Integration with Next-Auth

Using Next-Auth v5 (Auth.js)

app/api/autumn/[...autumn]/route.ts

import { nextAutumnHandler } from "autumn-js/adapters";
import { auth } from "@/auth";

const handler = nextAutumnHandler({
  identify: async (request) => {
    const session = await auth();
    
    if (!session?.user) return null;
    
    return {
      customerId: session.user.id,
      customerData: {
        name: session.user.name ?? undefined,
        email: session.user.email ?? undefined,
      },
    };
  },
});

export const { GET, POST, DELETE } = handler;

Using Next-Auth v4

app/api/autumn/[...autumn]/route.ts

import { nextAutumnHandler } from "autumn-js/adapters";
import { getServerSession } from "next-auth";
import { authOptions } from "@/lib/auth";

const handler = nextAutumnHandler({
  identify: async (request) => {
    const session = await getServerSession(authOptions);
    
    if (!session?.user) return null;
    
    return {
      customerId: session.user.id,
      customerData: {
        name: session.user.name,
        email: session.user.email,
      },
    };
  },
});

export const { GET, POST, DELETE } = handler;

Integration with Clerk

app/api/autumn/[...autumn]/route.ts

import { nextAutumnHandler } from "autumn-js/adapters";
import { auth } from "@clerk/nextjs/server";

const handler = nextAutumnHandler({
  identify: async (request) => {
    const { userId } = await auth();
    
    if (!userId) return null;
    
    return {
      customerId: userId,
    };
  },
});

export const { GET, POST, DELETE } = handler;

Integration with Custom JWT Auth

app/api/autumn/[...autumn]/route.ts

import { nextAutumnHandler } from "autumn-js/adapters";
import { verify } from "jsonwebtoken";

const handler = nextAutumnHandler({
  identify: async (request) => {
    const authHeader = request.headers.get("authorization");
    
    if (!authHeader?.startsWith("Bearer ")) return null;
    
    const token = authHeader.substring(7);
    
    try {
      const payload = verify(token, process.env.JWT_SECRET!) as {
        sub: string;
        email: string;
        name: string;
      };
      
      return {
        customerId: payload.sub,
        customerData: {
          email: payload.email,
          name: payload.name,
        },
      };
    } catch {
      return null;
    }
  },
});

export const { GET, POST, DELETE } = handler;

Integration with Cookies

app/api/autumn/[...autumn]/route.ts

import { nextAutumnHandler } from "autumn-js/adapters";
import { cookies } from "next/headers";
import { getUser } from "@/lib/session";

const handler = nextAutumnHandler({
  identify: async (request) => {
    const cookieStore = await cookies();
    const sessionId = cookieStore.get("session")?.value;
    
    if (!sessionId) return null;
    
    const user = await getUser(sessionId);
    
    return user
      ? {
          customerId: user.id,
          customerData: {
            name: user.name,
            email: user.email,
          },
        }
      : null;
  },
});

export const { GET, POST, DELETE } = handler;

Available Routes

Once configured with the catch-all route [...autumn], the following endpoints are automatically available:

Customer Routes

POST /api/autumn/getOrCreateCustomer - Get or create customer

Billing Routes

POST /api/autumn/attach - Attach a plan to customer
POST /api/autumn/previewAttach - Preview plan attachment
POST /api/autumn/updateSubscription - Update subscription
POST /api/autumn/previewUpdateSubscription - Preview subscription update
POST /api/autumn/openCustomerPortal - Open customer billing portal
POST /api/autumn/multiAttach - Attach multiple plans
POST /api/autumn/previewMultiAttach - Preview multiple plan attachments
POST /api/autumn/setupPayment - Setup payment method

Plan Routes

POST /api/autumn/listPlans - List available plans

Event Routes

POST /api/autumn/listEvents - List customer events
POST /api/autumn/aggregateEvents - Aggregate event data

Referral Routes

POST /api/autumn/createReferralCode - Create referral code
POST /api/autumn/redeemReferralCode - Redeem referral code

File Structure

Place your Autumn handler in a catch-all route:

app/
└── api/
    └── autumn/
        └── [...autumn]/
            └── route.ts

This structure captures all requests under /api/autumn/*.

How It Works

The adapter:

Receives requests to your catch-all route
Parses request method and body from the Next.js Request object
Calls your identify function to determine customer identity
Routes to the appropriate handler based on the URL path
Returns NextResponse with JSON body and proper status codes

TypeScript Support

The adapter is fully typed:

import type { NextAutumnHandlerOptions } from "autumn-js/adapters";

const options: NextAutumnHandlerOptions = {
  identify: async (request) => {
    // request is typed as Request
    const auth = request.headers.get("authorization");
    // ...
  },
  secretKey: process.env.AUTUMN_SECRET_KEY,
};

Error Handling

The adapter automatically handles errors:

401 Unauthorized - When identify returns null for protected routes
404 Not Found - When the route doesn’t exist
400 Bad Request - For invalid request bodies
500 Internal Server Error - For SDK errors

All errors return JSON:

{
  "code": "error_code",
  "message": "Human-readable error message"
}

Custom Path Prefix

If you place your route in a different location, update the pathPrefix:

app/api/billing/[...billing]/route.ts

const handler = nextAutumnHandler({
  identify: async (request) => {/* ... */},
  pathPrefix: "/api/billing",
});

export const { GET, POST, DELETE } = handler;

Environment Variables

Create a .env.local file:

# Required: Your Autumn secret key
AUTUMN_SECRET_KEY=sk_...

# Optional: Custom Autumn API URL (for self-hosted instances)
AUTUMN_API_URL=https://api.useautumn.com/v1

Middleware Integration

You can use Next.js middleware to protect your Autumn routes:

middleware.ts

import { NextResponse } from "next/server";
import type { NextRequest } from "next/server";

export function middleware(request: NextRequest) {
  // Your auth logic here
  const token = request.cookies.get("session")?.value;
  
  if (!token && request.nextUrl.pathname.startsWith("/api/autumn")) {
    return NextResponse.json(
      { code: "unauthorized", message: "Authentication required" },
      { status: 401 }
    );
  }
  
  return NextResponse.next();
}

export const config = {
  matcher: "/api/autumn/:path*",
};

Complete Example

Here’s a complete setup with Next-Auth:

app/api/autumn/[...autumn]/route.ts

import { nextAutumnHandler } from "autumn-js/adapters";
import { auth } from "@/auth";

const handler = nextAutumnHandler({
  identify: async (request) => {
    const session = await auth();
    
    if (!session?.user?.id) return null;
    
    return {
      customerId: session.user.id,
      customerData: {
        name: session.user.name ?? undefined,
        email: session.user.email ?? undefined,
      },
    };
  },
  secretKey: process.env.AUTUMN_SECRET_KEY,
  autumnURL: process.env.AUTUMN_API_URL,
});

// Export all supported methods
export const { GET, POST, DELETE } = handler;

.env.local

AUTUMN_SECRET_KEY=sk_test_...
AUTUMN_API_URL=https://api.useautumn.com/v1

Server Components

Since route handlers run on the server, you can safely use server-only code:

import { nextAutumnHandler } from "autumn-js/adapters";
import { db } from "@/lib/db";
import "server-only";

const handler = nextAutumnHandler({
  identify: async (request) => {
    // Direct database access is safe here
    const session = await db.session.findUnique({/* ... */});
    
    return session
      ? {
          customerId: session.userId,
          customerData: {
            name: session.user.name,
            email: session.user.email,
          },
        }
      : null;
  },
});

export const { GET, POST, DELETE } = handler;

Next Steps

Better Auth Integration

Use Autumn with Better Auth for authentication

React Hooks

Call Autumn endpoints from your React components

API Reference

Explore all available API endpoints

Billing Integration

Learn about attaching plans and billing

JavaScript/TypeScript

Python

Framework Adapters

Next.js Adapter

Overview

Installation

Quick Start

Configuration

Options

Route Handler Structure

Integration with Next-Auth

Using Next-Auth v5 (Auth.js)

Using Next-Auth v4

Integration with Clerk

Integration with Custom JWT Auth

Integration with Cookies

Available Routes

Customer Routes

Billing Routes

Plan Routes

Event Routes

Referral Routes

File Structure

How It Works

TypeScript Support

Error Handling

Custom Path Prefix

Environment Variables

Middleware Integration

Complete Example

Server Components

Next Steps

Better Auth Integration

React Hooks

API Reference

Billing Integration

Build docs developers (and LLMs) love

JavaScript/TypeScript

Python

Framework Adapters

​Overview

​Installation

​Quick Start

​Configuration

​Options

​Route Handler Structure

​Integration with Next-Auth

​Using Next-Auth v5 (Auth.js)

​Using Next-Auth v4

​Integration with Clerk

​Integration with Custom JWT Auth

​Integration with Cookies

​Available Routes

​Customer Routes

​Billing Routes

​Plan Routes

​Event Routes

​Referral Routes

​File Structure

​How It Works

​TypeScript Support

​Error Handling

​Custom Path Prefix

​Environment Variables

​Middleware Integration

​Complete Example

​Server Components

​Next Steps

Better Auth Integration

React Hooks

API Reference

Billing Integration

Build docs developers (and LLMs) love

Overview

Installation

Quick Start

Configuration

Options

Route Handler Structure

Integration with Next-Auth

Using Next-Auth v5 (Auth.js)

Using Next-Auth v4

Integration with Clerk

Integration with Custom JWT Auth

Integration with Cookies

Available Routes

Customer Routes

Billing Routes

Plan Routes

Event Routes

Referral Routes

File Structure

How It Works

TypeScript Support

Error Handling

Custom Path Prefix

Environment Variables

Middleware Integration

Complete Example

Server Components

Next Steps