Compare JSON - Diff API Responses

Capture JSON API responses on any page and compare two of them on comparejson.com.

Compare JSON captures JSON API responses as you browse and lets you diff any two of them side by side on comparejson.com — no copy-pasting, no manual file juggling. DEBUG API CHANGES IN SECONDS When a frontend bug appears, the first question is always "what changed in the response?". Instead of digging through DevTools network panels and pasting payloads into a diff tool, just: 1. Press Start in the extension popup 2. Reproduce the two scenarios (or browse two pages / two environments) 3. Pick a Base and a Contrast from the captured list 4. Click Compare — a visual diff opens instantly KEY FEATURES • Automatic capture — hooks into fetch/XHR and records every JSON response, including direct navigation to .json URLs • You control when — Start/Pause toggle, nothing is recorded while paused • Works across tabs — captures from all open tabs merge into one list, perfect for comparing staging vs. production • Full privacy control — capturing is off by default; one click clears everything • Toolbar badge — see the captured count at a glance • Powered by comparejson.com — structural JSON diff with smart array comparison (byIndex / LCS / unordered modes), syntax highlighting and collapsible tree view WHO IS IT FOR • Frontend developers debugging API contract changes • QA engineers verifying backend deployments • Anyone who needs to answer "what's different between these two JSON payloads?" PRIVACY Captured data never leaves your browser. It is stored locally in session storage, is cleared when you close the browser, and can be wiped at any time with the Clear button. No analytics, no tracking, no accounts.