@connectrpc/connect-next

Connect is a family of libraries for building and consuming APIs on different languages and platforms, and @connectrpc/connect brings type-safe APIs with Protobuf to TypeScript.

@connectrpc/connect-next provides a plugin for Next.js, the React Framework for the Web.

nextJsApiRouter()

Provide your Connect RPCs via Next.js API routes. To enable Connect in Next.js, add two files to your project:

.
├── connect.ts
└── pages
    └── api
        └── [[...connect]].ts

Note: Your Connect API routes need to be placed in pages/, but you can use the app/ directory for the App Router at the same time.

The new file connect.ts is where you register your RPCs:

// connect.ts
import { ConnectRouter } from "@connectrpc/connect";

export default function (router: ConnectRouter) {
  // implement rpc Say(SayRequest) returns (SayResponse)
  router.rpc(ElizaService, ElizaService.methods.say, async (req) => ({
    sentence: `you said: ${req.sentence}`,
  }));
}

pages/api/[[..connect]].ts is a Next.js catch-all API route:

// pages/api/[[..connect]].ts
import { nextJsApiRouter } from "@connectrpc/connect-next";
import { createValidateInterceptor } from "@connectrpc/validate";
import routes from "../../connect";

const { handler } = nextJsApiRouter({
  interceptors: [createValidateInterceptor()],
  routes,
});
export default handler;

// Required: Connect parses request bodies itself, so the Next.js body
// parser must be disabled. Without this, RPCs will fail.
export const config = {
  api: {
    bodyParser: false,
  },
};

With that server running, you can make requests with any Connect or gRPC-Web client. Note that Next.js serves all your RPCs with the /api prefix.

curl with the Connect protocol:

curl \
    --header "Content-Type: application/json" \
    --data '{"sentence": "I feel happy."}' \
    --http2-prior-knowledge \
    http://localhost:3000/api/connectrpc.eliza.v1.ElizaService/Say

Node.js with the gRPC-web protocol (using a transport from @connectrpc/connect-node):

import { createClient } from "@connectrpc/connect";
import { createGrpcWebTransport } from "@connectrpc/connect-node";
import { ElizaService } from "./gen/eliza_connect.js";

const transport = createGrpcWebTransport({
  baseUrl: "http://localhost:3000/api",
  httpVersion: "1.1",
});

const client = createClient(ElizaService, transport);
const { sentence } = await client.say({ sentence: "I feel happy." });
console.log(sentence); // you said: I feel happy.

A client for the web browser actually looks identical to this example - it would simply use createConnectTransport from @connectrpc/connect-web instead.

Note that support for gRPC is limited, since many gRPC clients require HTTP/2, and Next.js does not support the Node.js http2 module.

Deploying to Vercel

Currently, @connectrpc/connect-next does not support the Vercel Edge runtime. It requires the Node.js server runtime, which is used by default when deploying to Vercel.

Getting started

To get started with Connect, head over to the docs for a tutorial, or take a look at our example.