Docs Navigation

Server Adapters

Idiomatic Remix apps can generally be deployed anywhere because Remix adapt's the server's request/response to the Web Fetch API. It does this through adapters. We maintain a few adapters:

  • @remix-run/express
  • @remix-run/architect
  • @remix-run/vercel
  • @remix-run/netlify
  • @remix-run/cloudflare-workers

These adapters are imported into your server's entry and is not used inside of your Remix app itself.

If you initialized your app with npx create-remix@latest with something other than the built-in Remix App Server, you will note a server/index.js file that imports and uses one of these adapters.

If you're using the built-in Remix App Server, you don't interact with this API

Each adapter has the same API. In the future we may have helpers specific to the platform you're deploying to.

createRequestHandler

Creates a request handler for your server to serve the app. This is the ultimate entry point of your Remix application.

const {
  createRequestHandler
} = require("@remix-run/{adapter}");
createRequestHandler({ build, getLoadContext });

Here's a full example with express:

const express = require("express");
const {
  createRequestHandler
} = require("@remix-run/express");

const app = express();

// needs to handle all verbs (GET, POST, etc.)
app.all(
  "*",
  createRequestHandler({
    // `remix build` and `remix dev` output files to a build directory, you need
    // to pass that build to the request handler
    build: require("./build"),

    // return anything you want here to be available as `context` in your
    // loaders and actions. This is where you can bridge the gap between Remix
    // and your server
    getLoadContext(req, res) {
      return {};
    }
  })
);

Here's an example with Architect (AWS):

const {
  createRequestHandler
} = require("@remix-run/architect");
exports.handler = createRequestHandler({
  build: require("./build")
});

Here's an example with Vercel:

const {
  createRequestHandler
} = require("@remix-run/vercel");
module.exports = createRequestHandler({
  build: require("./build")
});

Here's an example with Netlify:

const path = require("path");
const {
  createRequestHandler
} = require("@remix-run/netlify");

const BUILD_DIR = path.join(process.cwd(), "netlify");

function purgeRequireCache() {
  // purge require cache on requests for "server side HMR" this won't let
  // you have in-memory objects between requests in development,
  // netlify typically does this for you, but we've found it to be hit or
  // miss and some times requires you to refresh the page after it auto reloads
  // or even have to restart your server
  for (const key in require.cache) {
    if (key.startsWith(BUILD_DIR)) {
      delete require.cache[key];
    }
  }
}

exports.handler =
  process.env.NODE_ENV === "production"
    ? createRequestHandler({ build: require("./build") })
    : (event, context) => {
        purgeRequireCache();
        return createRequestHandler({
          build: require("./build")
        })(event, context);
      };

Here's an example with the simplified Cloudflare Workers API:

import { createEventHandler } from "@remix-run/cloudflare-workers";

import * as build from "../build";

addEventListener("fetch", createEventHandler({ build }));

Here's an example with the lower level Cloudflare Workers API:

import {
  createRequestHandler,
  handleAsset
} from "@remix-run/cloudflare-workers";

import * as build from "../build";

const handleRequest = createRequestHandler({ build });

const handleEvent = async (event: FetchEvent) => {
  const response = await handleAsset(event, build);

  if (!response) {
    response = await handleRequest(event);
  }

  return response;
};

addEventListener("fetch", event => {
  try {
    event.respondWith(handleEvent(event));
  } catch (e: any) {
    if (process.env.NODE_ENV === "development") {
      event.respondWith(
        new Response(e.message || e.toString(), {
          status: 500
        })
      );
    }

    event.respondWith(
      new Response("Internal Error", { status: 500 })
    );
  }
});