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:

# 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

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:

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:

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:

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:

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:

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:

{
  "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):

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)

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

Tracing Test (Frontend + API Route)

<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

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:

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