---
title: "TanStack Start on Cloudflare"
description: "Learn how to instrument your TanStack Start app on Cloudflare Workers and capture your first errors with Sentry."
url: https://docs.sentry.io/platforms/javascript/guides/cloudflare/frameworks/tanstack-start/
---

# TanStack Start on Cloudflare | Sentry for Cloudflare

This guide is for TanStack Start deployed to **Cloudflare Workers** using the `@cloudflare/vite-plugin`. For Node.js-based deployments, see our [TanStack Start guide](https://docs.sentry.io/platforms/javascript/guides/tanstackstart-react.md).

## [Install](https://docs.sentry.io/platforms/javascript/guides/cloudflare/frameworks/tanstack-start.md#install)

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

Error Monitoring\[ ]Tracing\[ ]Session Replay\[ ]User Feedback

Want to learn more about these features?

* [**Issues**](https://docs.sentry.io/product/issues.md) (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**](https://docs.sentry.io/product/tracing.md): 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.
* [**Session Replay**](https://docs.sentry.io/product/session-replay/web.md): Get to the root cause of an issue faster by viewing a video-like reproduction of what was happening in the user's browser before, during, and after the problem.
* [**Logs**](https://docs.sentry.io/product/logs.md): 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.
* [**User Feedback**](https://docs.sentry.io/product/user-feedback.md): Collect feedback directly from users when they encounter errors, allowing them to describe what happened and provide context that helps you understand and resolve issues faster.
* [**Application Metrics**](https://docs.sentry.io/product/metrics.md) (always enabled): Track and analyze custom application metrics, such as response times and database query durations, to understand trends and patterns in your application's performance and behavior over time.

### [Install the Sentry SDK](https://docs.sentry.io/platforms/javascript/guides/cloudflare/frameworks/tanstack-start.md#install-the-sentry-sdk)

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

```bash
npm install @sentry/cloudflare --save
```

*Other available variations of the above snippet: yarn, pnpm*

## [Configure](https://docs.sentry.io/platforms/javascript/guides/cloudflare/frameworks/tanstack-start.md#configure)

When deploying TanStack Start to Cloudflare Workers, you need to wrap the server entry point with `Sentry.withSentry` from `@sentry/cloudflare`. TanStack Start allows you to create a custom server entry file for this purpose.

### [Wrangler Configuration](https://docs.sentry.io/platforms/javascript/guides/cloudflare/frameworks/tanstack-start.md#wrangler-configuration)

### [Create a Custom Server Entry](https://docs.sentry.io/platforms/javascript/guides/cloudflare/frameworks/tanstack-start.md#create-a-custom-server-entry)

Create a `src/server.ts` file that wraps the TanStack Start handler with Sentry.

Use `wrapFetchWithSentry` from `@sentry/tanstackstart-react` to instrument TanStack Start server functions with tracing.

Due to type differences between TanStack Start and Cloudflare Workers, you'll need to add a `// @ts-expect-error` comment as shown in the example. This is expected and doesn't affect functionality.

```typescript
import * as Sentry from "@sentry/cloudflare";
import { wrapFetchWithSentry } from "@sentry/tanstackstart-react";
import handler from "@tanstack/react-start/server-entry";

export default Sentry.withSentry(
  () => ({
    dsn: "https://<key>@o<orgId>.ingest.sentry.io/<projectId>",

    // ___PRODUCT_OPTION_START___ performance

    // Set tracesSampleRate to 1.0 to capture 100% of spans for tracing.
    tracesSampleRate: 1.0,
    // ___PRODUCT_OPTION_END___ performance
  }),
  // @ts-expect-error - handler is not typed as a Cloudflare handler
  wrapFetchWithSentry(handler),
);
```

### [Update Wrangler Configuration](https://docs.sentry.io/platforms/javascript/guides/cloudflare/frameworks/tanstack-start.md#update-wrangler-configuration)

Update your `wrangler.jsonc` (or `wrangler.toml`) to use your custom server entry:

```json
 {
   "name": "my-tanstack-app",
+     "main": "src/server.ts",
   // ... rest of config
 }
```

### [Configure Client-Side Sentry](https://docs.sentry.io/platforms/javascript/guides/cloudflare/frameworks/tanstack-start.md#configure-client-side-sentry)

Initialize Sentry in your `src/router.tsx` file for client-side error tracking:

```tsx
+import * as Sentry from "@sentry/tanstackstart-react";
 import { createRouter } from '@tanstack/react-router'

export const getRouter = () => {
  const router = createRouter();

+ if (!router.isServer) {
+   Sentry.init({
+     dsn: "https://<key>@o<orgId>.ingest.sentry.io/<projectId>",
+
+     integrations: [
+       // ___PRODUCT_OPTION_START___ performance
+       Sentry.tanstackRouterBrowserTracingIntegration(router),
+       // ___PRODUCT_OPTION_END___ performance
+       // ___PRODUCT_OPTION_START___ session-replay
+       Sentry.replayIntegration(),
+       // ___PRODUCT_OPTION_END___ session-replay
+       // ___PRODUCT_OPTION_START___ user-feedback
+       Sentry.feedbackIntegration({
+         // Additional SDK configuration goes in here, for example:
+         colorScheme: "system",
+       }),
+       // ___PRODUCT_OPTION_END___ user-feedback
+     ],
+     // ___PRODUCT_OPTION_START___ performance
+
+     // Set tracesSampleRate to 1.0 to capture 100% of spans for tracing.
+     tracesSampleRate: 1.0,
+     // ___PRODUCT_OPTION_END___ performance
+     // ___PRODUCT_OPTION_START___ session-replay
+
+     // Capture Replay for 10% of all sessions,
+     // plus for 100% of sessions with an error.
+     replaysSessionSampleRate: 0.1,
+     replaysOnErrorSampleRate: 1.0,
+     // ___PRODUCT_OPTION_END___ session-replay
+   });
+ }

  return router;
}
```

### [Capture Server-Side Errors](https://docs.sentry.io/platforms/javascript/guides/cloudflare/frameworks/tanstack-start.md#capture-server-side-errors)

To capture server-side errors from HTTP requests and server function calls, add Sentry's global middlewares to `createStart()` in your `src/start.ts` file.

The Sentry middleware should be the first middleware in the arrays to ensure all errors are captured.

SSR rendering exceptions are not captured by the middleware. Use `captureException` to manually capture those errors.

```tsx
import {
  sentryGlobalFunctionMiddleware,
  sentryGlobalRequestMiddleware,
} from "@sentry/tanstackstart-react";
import { createStart } from "@tanstack/react-start";

export const startInstance = createStart(() => {
  return {
    requestMiddleware: [sentryGlobalRequestMiddleware],
    functionMiddleware: [sentryGlobalFunctionMiddleware],
  };
});
```

### [Add Readable Stack Traces With Source Maps (Optional)](https://docs.sentry.io/platforms/javascript/guides/cloudflare/frameworks/tanstack-start.md#add-readable-stack-traces-with-source-maps-optional)

### [Control the Data You Send to Sentry (Optional)](https://docs.sentry.io/platforms/javascript/guides/cloudflare/frameworks/tanstack-start.md#control-the-data-you-send-to-sentry-optional)

By default, the SDK sends user identity data (IP address, ID, and similar) and other data like HTTP bodies and URL query parameters. This will give you rich debugging context.

The SDK always filters sensitive values whose keys match a built-in denylist, such as `auth` or `password`, and sends `[Filtered]` instead.

To send less data, turn off the categories you don't need in the `dataCollection` option. For the full list of categories and their defaults, [see the `dataCollection` options](https://docs.sentry.io/platforms/javascript/guides/cloudflare/configuration/options.md#dataCollection).

```javascript
Sentry.init({
  dsn: "https://<key>@o<orgId>.ingest.sentry.io/<projectId>",
  dataCollection: {
    userInfo: false,
    // other categories
  },
});
```

## [Verify Your Setup](https://docs.sentry.io/platforms/javascript/guides/cloudflare/frameworks/tanstack-start.md#verify-your-setup)

To verify Sentry is capturing errors, add a test button to one of your pages:

```tsx
<button
  type="button"
  onClick={() => {
    throw new Error("Sentry Test Error");
  }}
>
  Break the world
</button>;
```

Run your app with `wrangler dev` (or through your Vite build with Cloudflare plugin), click the button, and check your Sentry project for the error.

### [Logs](https://docs.sentry.io/platforms/javascript/guides/cloudflare/frameworks/tanstack-start.md#logs)

To verify that Sentry catches your logs, add some log statements to your application:

```javascript
Sentry.logger.info("User example action completed");

Sentry.logger.warn("Slow operation detected", {
  operation: "data_fetch",
  duration: 3500,
});

Sentry.logger.error("Validation failed", {
  field: "email",
  reason: "Invalid email",
});
```

### [Application Metrics NEW](https://docs.sentry.io/platforms/javascript/guides/cloudflare/frameworks/tanstack-start.md#application-metrics-)

[Application Metrics](https://docs.sentry.io/platforms/javascript/guides/cloudflare/metrics.md) are enabled by default.

Send test metrics from your app to verify that metrics are arriving in Sentry:

```javascript
Sentry.metrics.count("checkout.failed", 1);
Sentry.metrics.gauge("queue.depth", 42);
Sentry.metrics.distribution("api_latency", 187, {
  unit: "millisecond",
});
```

### [View Captured Data in Sentry](https://docs.sentry.io/platforms/javascript/guides/cloudflare/frameworks/tanstack-start.md#view-captured-data-in-sentry)

Now, head over to your project on [Sentry.io](https://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**](https://sentry.io/orgredirect/organizations/:orgslug/issues/) page and select an error from the issues list to view the full details and context of this error. For more details, see the [Issue Details documentation](https://docs.sentry.io/product/issues/issue-details.md).
* Open the [**Traces**](https://sentry.io/orgredirect/organizations/:orgslug/explore/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](https://docs.sentry.io/product/sentry-basics/getting-started-tutorial/generate-first-error.md#ui-walkthrough).
* Open the [**Logs**](https://sentry.io/orgredirect/organizations/:orgslug/explore/logs/) page and filter by service, environment, or search keywords to view log entries from your application. For an interactive UI walkthrough, click [here](https://docs.sentry.io/product/logs.md#overview).
* Open the [**Application Metrics**](https://sentry.io/orgredirect/organizations/:orgslug/explore/metrics) page to view and analyze your metrics. For more details, see this [interactive walkthrough](https://docs.sentry.io/product/metrics.md#overview).

## [Next Steps](https://docs.sentry.io/platforms/javascript/guides/cloudflare/frameworks/tanstack-start.md#next-steps)

At this point, you should have integrated Sentry and should already be sending 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:

* Explore [practical guides](https://docs.sentry.io/get-started/guides.md) on what to monitor, log, track, and investigate after setup
* Learn how to [manually capture errors](https://docs.sentry.io/platforms/javascript/guides/cloudflare/usage.md)
* Continue to [customize your configuration](https://docs.sentry.io/platforms/javascript/guides/cloudflare/configuration.md)
* Make use of [Cloudflare-specific features](https://docs.sentry.io/platforms/javascript/guides/cloudflare/features.md)
* Get familiar with [Sentry's product features](https://docs.sentry.io/product.md) like tracing, insights, and alerts

Are you having problems setting up the SDK?

* Check out setup instructions for other popular [frameworks on Cloudflare](https://docs.sentry.io/platforms/javascript/guides/cloudflare/frameworks.md)
* Find various support topics in [troubleshooting](https://docs.sentry.io/platforms/javascript/guides/cloudflare/troubleshooting.md)
* [Get support](https://www.sentry.help/en/)