Overfetch

Analyzes runtime API payload usage — tracks which response fields the UI actually uses.

Overfetch is a Chrome DevTools extension for frontend developers who want to understand how efficiently their app uses API responses.. It captures runtime API traffic, tracks which JSON response fields are actually read by the UI, and highlights unused data, duplicate requests, large payloads, and endpoint-level optimization opportunities. Use Overfetch to: Detect unused fields in API responses See payload waste by endpoint Compare used data vs unused data Find duplicate API calls Measure request size, response time, and efficiency Inspect payload structure directly in DevTools Identify backend or frontend optimization opportunities Overfetch works with common frontend API patterns including fetch, XHR, and JSON responses. Open Chrome DevTools, go to the Overfetch panel, interact with your app, and review the captured API usage report. It is useful for debugging SaaS apps, dashboards, ecommerce sites, internal tools, and any frontend application that consumes JSON APIs. Overfetch is built for local developer analysis and does not require backend changes.