Fetch / Edge Runtimes Adapter

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You can create a tRPC server within any edge runtime that follow the WinterCG, specifically the Minimum Common Web Platform API specification.

Some of these runtimes includes, but not limited to:

Cloudflare Workers
Deno Deploy
Vercel Edge Runtime (& Next.js Edge Runtime)

This also makes it easy to integrate into frameworks that uses the web platform APIs to represent requests and responses, such as:

Astro (SSR mode)
Remix
SolidStart

Example apps

<table> <thead> <tr> <th>Description</th> <th>Links</th> </tr> </thead> <tbody> <tr> <td>Cloudflare Workers example</td> <td> <a href="https://github.com/trpc/trpc/tree/main/examples/cloudflare-workers"> Source </a> </td> </tr> <tr> <td>Deno Deploy example</td> <td> <a href="https://github.com/trpc/trpc/tree/main/examples/deno-deploy"> Source </a> </td> </tr> <tr> <td>Next.js Edge Runtime example</td> <td> <a href="https://github.com/trpc/trpc/tree/main/examples/next-edge-runtime"> Source </a> </td> </tr> <tr> <td>Vercel Edge Runtime example</td> <td> <a href="https://github.com/trpc/trpc/tree/main/examples/vercel-edge-runtime"> Source </a> </td> </tr> </tbody> </table>

How to use tRPC server with an edge runtime

tRPC provides a fetch adapter that uses the native Request and Response APIs as input and output. The tRPC-specific code is the same across all runtimes, the only difference being how the response is returned.

tRPC includes an adapter for the native Fetch API out of the box. This adapter lets you convert your tRPC router into a Request handler that returns Response objects.

Required Web APIs

tRPC server uses the following Fetch APIs:

Request, Response
fetch
Headers
URL

If your runtime supports these APIs, you can use tRPC server.

:::tip Fun fact: that also means you can use a tRPC server in your browser! :::

Common setup

Install dependencies

:::tip You can skip this step if you use Deno Deploy. :::

npm install @trpc/server zod

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yarn add @trpc/server zod

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pnpm add @trpc/server zod

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bun add @trpc/server zod

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Zod isn't a required dependency, but it's used in the sample router below.

Create the router

First of all you need a router to handle your queries, mutations and subscriptions.

A sample router is given below, save it in a file named router.ts.

<details> <summary>router.ts</summary>

import { initTRPC } from '@trpc/server';
import { z } from 'zod';
import { Context } from './context';

type User = {
  id: string;
  name: string;
  bio?: string;
};

const users: Record<string, User> = {};

export const t = initTRPC.context<Context>().create();

export const appRouter = t.router({
  getUserById: t.procedure.input(z.string()).query((opts) => {
    return users[opts.input]; // input type is string
  }),
  createUser: t.procedure
    // validate input with Zod
    .input(
      z.object({
        name: z.string().min(3),
        bio: z.string().max(142).optional(),
      }),
    )
    .mutation((opts) => {
      const id = Date.now().toString();
      const user: User = { id, ...opts.input };
      users[user.id] = user;
      return user;
    }),
});

// export type definition of API
export type AppRouter = typeof appRouter;

</details>

If your router file starts getting too big, split your router into several subrouters each implemented in its own file. Then merge them into a single root appRouter.

Create the context

Then you need a context that will be created for each request.

A sample context is given below, save it in a file named context.ts:

<details> <summary>context.ts</summary>

import { FetchCreateContextFnOptions } from '@trpc/server/adapters/fetch';

export function createContext({
  req,
  resHeaders,
}: FetchCreateContextFnOptions) {
  const user = { name: req.headers.get('username') ?? 'anonymous' };
  return { req, resHeaders, user };
}

export type Context = Awaited<ReturnType<typeof createContext>>;

</details>

Runtimes-specific setup

Astro

import { fetchRequestHandler } from '@trpc/server/adapters/fetch';
import type { APIRoute } from 'astro';
import { createContext } from '../../server/context';
import { appRouter } from '../../server/router';

export const all: APIRoute = (opts) => {
  return fetchRequestHandler({
    endpoint: '/trpc',
    req: opts.request,
    router: appRouter,
    createContext,
  });
};

Cloudflare Worker

:::note You need the Wrangler CLI to run Cloudflare Workers. :::

Create Cloudflare Worker

import { fetchRequestHandler } from '@trpc/server/adapters/fetch';
import { createContext } from './context';
import { appRouter } from './router';

export default {
  async fetch(request: Request): Promise<Response> {
    return fetchRequestHandler({
      endpoint: '/trpc',
      req: request,
      router: appRouter,
      createContext,
    });
  },
};

Run wrangler dev server.ts and your endpoints will be available via HTTP!

Endpoint	HTTP URI
`getUser`	`GET http://localhost:8787/trpc/getUserById?input=INPUT`

where INPUT is a URI-encoded JSON string. | | createUser | POST http://localhost:8787/trpc/createUser

with req.body of type User |

Deno Oak

:::note This assumes you have Deno installed and setup. Refer to their getting started guide for more information. :::

Update the imports in `router.ts`

import { initTRPC } from 'npm:@trpc/server';
import { z } from 'npm:zod';
import { Context } from './context.ts';

Update the imports in `context.ts`

import { FetchCreateContextFnOptions } from 'npm:@trpc/server/adapters/fetch';

Use `fetchRequestHandler` with Oak in `app.ts`

import { Application, Router } from 'https://deno.land/x/oak/mod.ts';
import { fetchRequestHandler } from 'npm:@trpc/server/adapters/fetch';
import { createContext } from './context.ts';
import { appRouter } from './router.ts';

const app = new Application();
const router = new Router();

router.all('/trpc/(.*)', async (ctx) => {
  const res = await fetchRequestHandler({
    endpoint: '/trpc',
    req: new Request(ctx.request.url, {
      headers: ctx.request.headers,
      body:
        ctx.request.method !== 'GET' && ctx.request.method !== 'HEAD'
          ? ctx.request.body({ type: 'stream' }).value
          : void 0,
      method: ctx.request.method,
    }),
    router: appRouter,
    createContext,
  });

  ctx.response.status = res.status;
  ctx.response.headers = res.headers;
  ctx.response.body = res.body;
});

app.use(router.routes());
app.use(router.allowedMethods());

await app.listen({ port: 3000 });

Deno Deploy

:::note This assumes you have Deno installed and setup. Refer to their getting started guide for more information. :::

:::tip See our example Deno Deploy app for a working example. :::

Update the imports in `router.ts`

import { initTRPC } from 'npm:@trpc/server';
import { z } from 'npm:zod';
import { Context } from './context.ts';

Update the imports in `context.ts`

import { FetchCreateContextFnOptions } from 'npm:@trpc/server/adapters/fetch';

Create Deno Deploy Function

import { fetchRequestHandler } from 'npm:@trpc/server/adapters/fetch';
import { createContext } from './context.ts';
import { appRouter } from './router.ts';

function handler(request) {
  return fetchRequestHandler({
    endpoint: '/trpc',
    req: request,
    router: appRouter,
    createContext,
  });
}

Deno.serve(handler);

Run deno run --allow-net=:8000 --allow-env ./server.ts and your endpoints will be available via HTTP!

Endpoint	HTTP URI
`getUser`	`GET http://localhost:8000/trpc/getUserById?input=INPUT`

where INPUT is a URI-encoded JSON string. | | createUser | POST http://localhost:8000/trpc/createUser

with req.body of type User |

Next.js Edge Runtime

See a full example here.

Remix

import type { ActionArgs, LoaderArgs } from '@remix-run/node';
import { fetchRequestHandler } from '@trpc/server/adapters/fetch';
import { createContext } from '~/server/context';
import { appRouter } from '~/server/router';

export const loader = async (args: LoaderArgs) => {
  return handleRequest(args);
};
export const action = async (args: ActionArgs) => {
  return handleRequest(args);
};
function handleRequest(args: LoaderArgs | ActionArgs) {
  return fetchRequestHandler({
    endpoint: '/trpc',
    req: args.request,
    router: appRouter,
    createContext,
  });
}

SolidStart

import { fetchRequestHandler } from '@trpc/server/adapters/fetch';
import type { APIEvent } from 'solid-start';
import { createContext } from '../../server/context';
import { appRouter } from '../../server/router';

const handler = (event: APIEvent) =>
  fetchRequestHandler({
    endpoint: '/api/trpc',
    req: event.request,
    router: appRouter,
    createContext,
  });
export { handler as GET, handler as POST };

Vercel Edge Runtime

:::note See the official Vercel Edge Runtime documentation for more information. :::

:::tip See our example Vercel Edge Runtime app for a working example. :::

Install dependencies

npm install -g edge-runtime

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yarn global add edge-runtime

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pnpm add -g edge-runtime

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bun add -g edge-runtime

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Create Edge Runtime Function

import { fetchRequestHandler } from '@trpc/server/adapters/fetch';
import { createContext } from './context';
import { appRouter } from './router';

addEventListener('fetch', (event) => {
  return event.respondWith(
    fetchRequestHandler({
      endpoint: '/trpc',
      req: event.request,
      router: appRouter,
      createContext,
    }),
  );
});

Run edge-runtime --listen server.ts --port 3000 and your endpoints will be available via HTTP!

Endpoint	HTTP URI
`getUser`	`GET http://localhost:3000/trpc/getUserById?input=INPUT`

where INPUT is a URI-encoded JSON string. | | createUser | POST http://localhost:3000/trpc/createUser

with req.body of type User |

Example apps

How to use tRPC server with an edge runtime

Required Web APIs

Common setup

Install dependencies

Create the router

Create the context

Runtimes-specific setup

Astro

Cloudflare Worker

Create Cloudflare Worker

Deno Oak

Update the imports in router.ts

Update the imports in context.ts

Use fetchRequestHandler with Oak in app.ts

Deno Deploy

Update the imports in router.ts

Update the imports in context.ts

Create Deno Deploy Function

Next.js Edge Runtime

Remix

SolidStart

Vercel Edge Runtime

Install dependencies

Create Edge Runtime Function

Update the imports in `router.ts`

Update the imports in `context.ts`

Use `fetchRequestHandler` with Oak in `app.ts`

Update the imports in `router.ts`

Update the imports in `context.ts`