How to Track Errors in My App

Create a Sentry account

Sign up at sentry.io and create a new project for your framework (React, Next.js, Node.js, etc.). The free tier includes 5,000 errors/month, which is more than enough for an early-stage app.

Install the Sentry SDK

Install the appropriate Sentry package for your framework. For React apps, install @sentry/react. For Next.js, use @sentry/nextjs which includes both client and server error tracking.

npm install @sentry/react
# or for Next.js
npm install @sentry/nextjs

Initialize Sentry in your app

Add the Sentry initialization code to your app entry point. Replace YOUR_SENTRY_DSN with the DSN from your Sentry project settings. This captures all unhandled errors automatically.

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

Sentry.init({
  dsn: "YOUR_SENTRY_DSN",
  integrations: [
    Sentry.browserTracingIntegration(),
    Sentry.replayIntegration(),
  ],
  tracesSampleRate: 1.0,
  replaysOnErrorSampleRate: 1.0,
});

Configure alert rules

In your Sentry dashboard, go to Alerts and create a rule that emails you when a new error occurs. Set it to notify on first occurrence of a new issue, not on every error — this prevents alert fatigue while ensuring you know about new problems.

Test with a deliberate error

Add a temporary button that throws an error to verify Sentry is working. Click it, then check your Sentry dashboard. You should see the error with a full stack trace. Remove the test button after confirming.

<button onClick={() => { throw new Error("Sentry test error"); }}>
  Test Error Tracking
</button>