> All Skills > SDK Setup > TanStack Start React SDK

Sentry TanStack Start React SDK

Opinionated wizard that scans your TanStack Start React project and guides you through complete Sentry setup for browser and server runtimes.

Invoke This Skill When

• User asks to "add Sentry to TanStack Start" or "set up Sentry" in a TanStack Start React app
• User wants to install or configure @sentry/tanstackstart-react
• User wants error monitoring, tracing, session replay, logs, or user feedback for TanStack Start React
• User asks about sentryTanstackStart, wrapFetchWithSentry, instrument.server.mjs, or TanStack Start middleware instrumentation

> Note: This SDK is currently alpha and documented as compatible with TanStack Start 1.0 RC. > Always verify against docs.sentry.io/platforms/javascript/guides/tanstackstart-react/ before implementing.

Phase 1: Detect

Run these commands to understand the project before making any recommendations:

bash
# Detect TanStack Start / Router and existing Sentry
cat package.json | grep -E '"@tanstack/react-start"|"@tanstack/react-router"|"@sentry/tanstackstart-react"'

# Check if Sentry is already present
cat package.json | grep '"@sentry/'

# Detect key files used by the TanStack Start setup
ls src/router.tsx src/start.ts src/server.ts instrument.server.mjs vite.config.ts vite.config.js 2>/dev/null

# Check whether source map upload credentials are configured
cat .env .env.local .env.sentry-build-plugin 2>/dev/null | grep "SENTRY_AUTH_TOKEN"

# Detect deployment hints in scripts
cat package.json | grep -E '"dev"|"build"|"start"|NODE_OPTIONS|--import'

# Detect logging libraries
cat package.json | grep -E '"pino"|"winston"|"loglevel"'

# Detect companion backend directories
ls ../backend ../server ../api 2>/dev/null
cat ../go.mod ../requirements.txt ../Gemfile ../pom.xml 2>/dev/null | head -3

What to determine:

| Question | Impact | |----------|--------| | @tanstack/react-start present? | Confirms this skill is the right setup path | | @sentry/tanstackstart-react already installed? | Skip install and go to feature tuning | | src/router.tsx exists? | Client-side Sentry.init placement | | src/start.ts exists? | Global middleware setup for server-side errors | | src/server.ts exists? | Server entry instrumentation placement | | instrument.server.mjs exists? | Runtime startup instrumentation path | | vite.config.ts exists? | Add sentryTanstackStart plugin and source maps | | SENTRY_AUTH_TOKEN configured? | Source map upload readiness | | Backend directory found? | Trigger Phase 4 cross-link suggestion |

Phase 2: Recommend

Present a concrete recommendation based on what you found. Do not ask open-ended questions — lead with a proposal:

Recommended (core coverage):

• ✅ Error Monitoring — always; captures unhandled client and server errors
• ✅ Tracing — high-value for request and route timing across browser and server
• ✅ Session Replay — recommended for user-facing apps

Optional (enhanced observability):

• ⚡ Logs — recommend when structured log search and log-to-trace correlation are needed
• ⚡ User Feedback — recommend when product teams want in-app issue reports

Recommendation logic:

| Feature | Recommend when... | |---------|------------------| | Error Monitoring | Always — non-negotiable baseline | | Tracing | Usually yes for TanStack Start; route + fetch instrumentation gives immediate value | | Session Replay | User-facing app, login flows, checkout flows, or hard-to-reproduce UX bugs | | Logs | Existing logging strategy, support workflow, or trace/log correlation needs | | User Feedback | Team wants direct user reports without leaving the app |

Propose: "I recommend Error Monitoring + Tracing + Session Replay. Want me to also enable Logs and User Feedback?"

Phase 3: Guide

Install

bash
npm install @sentry/tanstackstart-react --save

Configure Client-Side Sentry in src/router.tsx

Initialize Sentry inside the router factory and gate it to the browser:

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: "___PUBLIC_DSN___",
      sendDefaultPii: true,

      integrations: [
        Sentry.tanstackRouterBrowserTracingIntegration(router),
        Sentry.replayIntegration(),
        Sentry.feedbackIntegration({
          colorScheme: "system",
        }),
      ],

      enableLogs: true,
      tracesSampleRate: 1.0,
      replaysSessionSampleRate: 0.1,
      replaysOnErrorSampleRate: 1.0,
    });
  }

  return router;
};

Configure Server-Side Sentry in instrument.server.mjs

Create instrument.server.mjs in project root:

javascript
import * as Sentry from "@sentry/tanstackstart-react";

Sentry.init({
  dsn: "___PUBLIC_DSN___",
  sendDefaultPii: true,
  enableLogs: true,
  tracesSampleRate: 1.0,
});

Configure Vite Plugin in vite.config.ts

sentryTanstackStart should be the last plugin:

typescript
import { defineConfig } from "vite";
import { sentryTanstackStart } from "@sentry/tanstackstart-react/vite";
import { tanstackStart } from "@tanstack/react-start/plugin/vite";

export default defineConfig({
  plugins: [
    tanstackStart(),
    sentryTanstackStart({
      org: "___ORG_SLUG___",
      project: "___PROJECT_SLUG___",
      authToken: process.env.SENTRY_AUTH_TOKEN,
    }),
  ],
});

If the token is stored in .env, load it with loadEnv in the Vite config before passing it to the plugin.

Instrument Server Entry Point in src/server.ts

Wrap the fetch handler with wrapFetchWithSentry:

typescript
import { wrapFetchWithSentry } from "@sentry/tanstackstart-react";
import handler, { createServerEntry } from "@tanstack/react-start/server-entry";

export default createServerEntry(
  wrapFetchWithSentry({
    fetch(request: Request) {
      return handler.fetch(request);
    },
  }),
);

Add Global Server Middleware in src/start.ts

These middleware capture server-side request and function errors:

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

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

Sentry middleware should be first in each array.

Runtime Startup Patterns

Choose one runtime method:

| Runtime pattern | Use when... | Notes | |---|---|---| | --import flag | You can control Node startup flags | Preferred for production monitoring | | Direct import in src/server.ts | Host restricts startup flags (for example serverless hosts) | Limits instrumentation to native Node APIs |

--import examples:

json
{
  "scripts": {
    "dev": "NODE_OPTIONS='--import ./instrument.server.mjs' vite dev --port 3000",
    "build": "vite build && cp instrument.server.mjs .output/server",
    "start": "node --import ./.output/server/instrument.server.mjs .output/server/index.mjs"
  }
}

Direct import fallback (top of src/server.ts):

typescript
import "../instrument.server.mjs";

For Each Agreed Feature

Walk through features one at a time. Load the reference file, follow steps exactly, and verify before moving on:

| Feature | Reference | Load when... | |---------|-----------|-------------| | Error Monitoring | ${SKILL_ROOT}/references/error-monitoring.md | Always | | Tracing | ${SKILL_ROOT}/references/tracing.md | Route/API performance visibility needed | | Session Replay | ${SKILL_ROOT}/references/session-replay.md | User-facing app | | Logs | ${SKILL_ROOT}/references/logging.md | Structured logs and correlation needed | | User Feedback | ${SKILL_ROOT}/references/user-feedback.md | In-app feedback collection needed | | TanStack Start Features | ${SKILL_ROOT}/references/tanstackstart-features.md | Server entry, Vite plugin, source maps, runtime startup |

For each feature: Read ${SKILL_ROOT}/references/<feature>.md, follow steps exactly, verify it works.

Configuration Reference

Key Sentry.init() Options

| Option | Type | Default | Notes | |--------|------|---------|-------| | dsn | string | — | Required; SDK is disabled when empty | | sendDefaultPii | boolean | false | Sends request headers and IP-derived user context | | integrations | Integration[] | SDK defaults | Include TanStack Router tracing, replay, feedback as needed | | enableLogs | boolean | false | Enables Sentry.logger.* APIs | | tracesSampleRate | number | — | 1.0 in development, lower in production | | replaysSessionSampleRate | number | — | Fraction of all sessions recorded | | replaysOnErrorSampleRate | number | — | Fraction of error sessions recorded | | tunnel | string | — | Optional ad-blocker bypass endpoint | | debug | boolean | false | SDK diagnostic logging |

TanStack Start-Specific APIs

| API | Purpose | |-----|---------| | tanstackRouterBrowserTracingIntegration(router) | Browser navigation tracing | | wrapFetchWithSentry(...) | Server request tracing + error capture on fetch handler | | sentryGlobalRequestMiddleware | Captures request-level server errors | | sentryGlobalFunctionMiddleware | Captures server function errors | | sentryTanstackStart({...}) | Vite plugin for source maps and middleware instrumentation |

Verification

Trigger test events to confirm Sentry receives data.

Issues Test (Frontend)

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

Tracing Test (Frontend + API Route)

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

Logs Test

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" });

Confirm in Sentry:

• Issues: frontend/server errors appear
• Traces: browser and server spans appear
• Replays: session replay appears when enabled
• Logs: log lines appear when enableLogs: true
• User Feedback: submissions appear when feedback integration is enabled

Phase 4: Cross-Link

After completing TanStack Start setup, check whether a companion backend exists without Sentry:

bash
ls ../backend ../server ../api ../go ../python 2>/dev/null
cat ../go.mod ../requirements.txt ../pyproject.toml ../Gemfile ../pom.xml 2>/dev/null | head -5

If a backend exists without Sentry configured, suggest the matching skill:

| Backend detected | Suggest skill | |------------------|--------------| | Go (go.mod) | sentry-go-sdk | | Python (requirements.txt, pyproject.toml) | sentry-python-sdk | | Ruby (Gemfile) | sentry-ruby-sdk | | Java (pom.xml, build.gradle) | Use @sentry/java docs | | Node.js backend services | sentry-node-sdk |

Troubleshooting

| Issue | Solution | |-------|----------| | Events not appearing | Set debug: true, verify DSN, and ensure client/server init files both run | | No server traces | Confirm src/server.ts uses wrapFetchWithSentry and runtime loads instrument.server.mjs | | Server errors missing from route handlers | Ensure sentryGlobalRequestMiddleware and sentryGlobalFunctionMiddleware are first in arrays | | Source maps not resolving | Verify SENTRY_AUTH_TOKEN, org, and project in sentryTanstackStart config | | SENTRY_AUTH_TOKEN undefined in Vite config | Use loadEnv(mode, process.cwd(), "") or .env.sentry-build-plugin | | Replay not recording | Ensure replayIntegration() is in integrations and sample rates are non-zero | | Feedback widget not visible | Confirm feedbackIntegration() is configured and check CSS z-index conflicts | | Logs missing in Sentry | Set enableLogs: true and use Sentry.logger.* APIs | | Direct-import setup misses library spans | Prefer --import startup when possible; direct import supports native Node instrumentation only | | SSR rendering exceptions not auto-captured | Capture manually with Sentry.captureException in error boundaries / fallback handlers |