Explore interactive demos showing how TrackJS helps you diagnose and fix JavaScript errors faster. Watch short videos highlighting our Telemetry Timeline, powerful filtering tools, and ignore rules that …

TrackJS seamlessly integrates with your website code to track production errors from real users.

TrackJS tracks JavaScript errors from your frontend web applications with all the context you need to understand the impact and fix bugs fast.

TrackJS is the easiest way to Monitor and Report JavaScript Errors from your Web Application. Get started tracking JavaScript exceptions and fix bugs in minutes.

Jan 28, 2026 · The JSON variant shows as Unexpected end of JSON input and occurs when JSON.parse() (or response.json()) receives an empty string, truncated data, or non-JSON content. …

Sep 17, 2025 · This SyntaxError happens when code tries to parse HTML as JSON. Usually your API returned an HTML error page (like a 503 gateway error) instead of the JSON data you ...

Dec 10, 2025 · Understanding the Root Cause “Invalid or unexpected token” can stem from several sources, with invisible characters being the most common and frustrating: 1. Smart Quotes from …

Compare the strengths and weaknesses for Frontend Error Monitoring tools. We'll look at the focus, features, and pricing of the top contenders so you can pick the ...

4 days ago · Safari throws this when JavaScript tries to call the WKWebView native bridge, but the page is running in a normal browser context where `window.webkit.messageHandlers` doesn't exist. Fix it …

Jun 24, 2025 · // Scenario that might trigger loop limit exceeded const observer = new ResizeObserver((entries) => { entries.forEach(entry => { // Complex calculations that take ...