Remix on Cloudflare

Learn how to instrument your Remix app on Cloudflare Workers and Pages and capture your first errors with Sentry.

You need:

A Sentry account and project
Your application up and running
Remix version 2.0.0+

Choose the features you want to configure, and this guide will show you how:

Want to learn more about these features?

Issues (always enabled): Sentry's core error monitoring product that automatically reports errors, uncaught exceptions, and unhandled rejections. If you have something that looks like an exception, Sentry can capture it.
Tracing: Track software performance while seeing the impact of errors across multiple systems. For example, distributed tracing allows you to follow a request from the frontend to the backend and back.
Logs: Centralize and analyze your application logs to correlate them with errors and performance issues. Search, filter, and visualize log data to understand what's happening in your applications.

Run the command for your preferred package manager to add the Sentry SDK to your application:

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npm install @sentry/remix --save

Create a client file entry.client.tsx in the app folder of your project if you don't have one already. In this file, import and initialize the Sentry SDK:

entry.client.tsx

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import { useLocation, useMatches } from "@remix-run/react";
import * as Sentry from "@sentry/remix";
import { useEffect } from "react";

Sentry.init({
  dsn: "https://examplePublicKey@o0.ingest.sentry.io/0example-org / example-project",

  // Adds request headers and IP for users, for more info visit:
  // https://docs.sentry.io/platforms/javascript/guides/remix/configuration/options/#sendDefaultPii
  sendDefaultPii: true,

  integrations: [
    //  performance
    Sentry.browserTracingIntegration({
      useEffect,
      useLocation,
      useMatches,
    }),
    //  performance
    //  session-replay
    // Replay is only available in the client
    Sentry.replayIntegration(),
    //  session-replay
    //  user-feedback
    Sentry.feedbackIntegration({
      // Additional SDK configuration goes in here, for example:
      colorScheme: "system",
    }),
    //  user-feedback
  ],
  //  performance

  // Set tracesSampleRate to 1.0 to capture 100%
  // of transactions for tracing.
  // We recommend adjusting this value in production
  // Learn more at
  // https://docs.sentry.io/platforms/javascript/configuration/options/#traces-sample-rate
  tracesSampleRate: 1.0,

  // Set `tracePropagationTargets` to control for which URLs distributed tracing should be enabled
  tracePropagationTargets: ["localhost", /^https:\/\/yourserver\.io\/api/],
  //  performance
  //  session-replay

  // Capture Replay for 10% of all sessions,
  // plus for 100% of sessions with an error
  // Learn more at
  // https://docs.sentry.io/platforms/javascript/session-replay/configuration/#general-integration-configuration
  replaysSessionSampleRate: 0.1,
  replaysOnErrorSampleRate: 1.0,
  //  session-replay
  //  logs

  // Enable logs to be sent to Sentry
  enableLogs: true,
  //  logs
});

To capture errors from your ErrorBoundary, define it in root.tsx to act as a fallback for all routes or create route-specific error boundaries in your route components.

In your ErrorBoundary component, use Sentry.captureRemixErrorBoundaryError to send the captured error to Sentry:

root.tsx

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import { captureRemixErrorBoundaryError } from "@sentry/remix";

export const ErrorBoundary = () => {
  const error = useRouteError();

  captureRemixErrorBoundaryError(error);

  return <div> ... </div>;
};

Wrap your Remix root component with withSentry to capture performance data:

root.tsx

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import {
  Links,
  LiveReload,
  Meta,
  Outlet,
  Scripts,
  ScrollRestoration,
} from "@remix-run/react";

import { withSentry } from "@sentry/remix";

function App() {
  return (
    <html>
      <head>
        <Meta />
        <Links />
      </head>
      <body>
        <Outlet />
        <ScrollRestoration />
        <Scripts />
        <LiveReload />
      </body>
    </html>
  );
}

export default withSentry(App);

Create a _middleware.js file in your functions directory if you don't have one already. In this file, import and initialize the Sentry Cloudflare SDK:

functions/_middleware.js

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import * as Sentry from "@sentry/cloudflare";

export const onRequest = [
  // Make sure Sentry is the first middleware
  Sentry.sentryPagesPlugin((context) => ({
    dsn: "https://examplePublicKey@o0.ingest.sentry.io/0example-org / example-project",

    // Adds request headers and IP for users, for more info visit: and captures action formData attributes
    // https://docs.sentry.io/platforms/javascript/guides/remix/configuration/options/#sendDefaultPii
    sendDefaultPii: true,
    //  performance

    // Set tracesSampleRate to 1.0 to capture 100%
    // of transactions for tracing.
    // We recommend adjusting this value in production
    // Learn more at
    // https://docs.sentry.io/platforms/javascript/configuration/options/#traces-sample-rate
    tracesSampleRate: 1.0,
    //  performance
    //  logs

    // Enable logs to be sent to Sentry
    enableLogs: true,
    //  logs

    // Optionally capture action formData attributes with errors.
    // This requires `sendDefaultPii` set to true as well.
    captureActionFormDataKeys: {
      key_x: true,
      key_y: true,
    },
  })),
  // Add more middlewares here
];

To automatically capture server-side errors, instrument the handleError function in your server entry point (entry.server.tsx). You can wrap your custom error handler with wrapHandleErrorWithSentry or directly use sentryHandleError:

entry.server.tsx

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import * as Sentry from "@sentry/remix";

export const handleError = Sentry.wrapHandleErrorWithSentry(
  (error, { request }) => {
    // Custom handleError implementation
  },
);

// Alternative: Use the Sentry utility function if you don't need to wrap a custom function
export const handleError = Sentry.sentryHandleError;

Tip

Sentry's Remix SDK automatically records your action and loader transactions for performance monitoring. You can also initialize Sentry's database integrations, such as Prisma, to get spans for your database calls.

Since the SDK needs access to the AsyncLocalStorage API, you need to set either the nodejs_compat or nodejs_als compatibility flags in your wrangler.(jsonc|toml) configuration file:

wrangler.jsonc

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{
  "compatibility_flags": [
    "nodejs_als",
    // "nodejs_compat"
  ],
}

Additionally, add the CF_VERSION_METADATA binding in the same file:

wrangler.jsonc

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{
  // ...
  "version_metadata": {
    "binding": "CF_VERSION_METADATA",
  },
}

To upload source maps for clear error stack traces, add your Sentry auth token, organization, and project slug in your vite.config.ts file:

Not using Vite?

Check our Source Maps documentation for alternative setup options.

vite.config.ts

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import { defineConfig } from "vite";
import { vitePlugin as remix } from "@remix-run/dev";
import { sentryVitePlugin } from "@sentry/vite-plugin";

export default defineConfig({
  plugins: [
    remix({
      // ... your Remix plugin options
    }),
    sentryVitePlugin({
      // If you use .sentryclirc or environment variables,
      // you don't need to specify these options
      org: "example-org",
      project: "example-project",
      // store your auth token in an environment variable
      authToken: process.env.SENTRY_AUTH_TOKEN,
    }),
  ],

  build: {
    sourcemap: true,
    // ... rest of your Vite build options
  },
});

To keep your auth token secure, always store it in an environment variable instead of directly in your files:

.env

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SENTRY_AUTH_TOKEN=sntrys_YOUR_TOKEN_HERE

Let's test your setup and confirm that Sentry is working correctly and sending data to your Sentry project.

To verify that Sentry captures errors and creates issues in your Sentry project, add a test button to one of your pages:

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<button
  type="button"
  onClick={() => {
    throw new Error("Sentry Example Frontend Error");
  }}
>
  <span>Throw Sample Error</span>
</button>;

To test your tracing configuration, update the previous code snippet by calling a non-existing route and starting a trace to measure the time it takes for the execution of your code:

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<button
  type="button"
  onClick={async () => {
    await Sentry.startSpan(
      {
        name: "Example Frontend Span",
        op: "test",
      },
      async () => {
        const res = await fetch("/api/sentry-example-api");
        if (!res.ok) {
          throw new Error("Sentry Example Frontend Error");
        }
      },
    );
  }}
>
  <span>Throw Sample Error</span>
</button>;

Open the page in a browser (for most Remix applications, this will be at localhost:3000) and click the button to trigger the frontend error and a trace.

Important

Errors triggered from within your browser's developer tools (like the browser console) are sandboxed, so they will not trigger Sentry's error monitoring.

Now, head over to your project on Sentry.io to view the collected data (it takes a couple of moments for the data to appear).

Need help locating the captured errors in your Sentry project?

Open the Issues page and select an error from the issues list to view the full details and context of this error. For more details, see this interactive walkthrough.
Open the Traces page and select a trace to reveal more information about each span, its duration, and any errors. For an interactive UI walkthrough, click here.
Open the Logs page and filter by service, environment, or search keywords to view log entries from your application. For an interactive UI walkthrough, click here.

At this point, you should have integrated Sentry into your Remix application and should already be sending error and performance data to your Sentry project.

Now's a good time to customize your setup and look into more advanced topics. Our next recommended steps for you are:

Learn how to manually capture errors
Continue to customize your configuration
Get familiar with Sentry's product features like tracing, insights, and alerts

Are you having problems setting up the SDK?

If you encountered issues with the manual setup, try our installation wizard
Find various support topics in Cloudflare troubleshooting and Remix troubleshooting
Get support

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