Decoy

Decoy — Chrome DevTools Network Sampler & API Mocker Decoy is a Chrome DevTools panel that lets you capture, save, and replay real API responses — without touching your backend or writing any mock servers. What it does Open the Decoy panel in DevTools, click Live, and it silently intercepts every fetch and XHR request your page makes. Pick any captured request, save it as a preset, then toggle it on to have Decoy serve that exact response the next time the same endpoint is called — complete with original headers, status codes, and response body. Key features Zero-config capture — no proxy, no browser flags, no code changes. Works on any page, any framework. Preset library — save responses by endpoint and method. Edit the status code, latency, headers, or body inline before replaying. Persistent mocks — active mocks survive DevTools panel close and reopen, so your session isn't disrupted. Latency simulation — set artificial delays to test loading states and timeout handling. Live mode — bulk-activate all presets at once to mock an entire API surface during development or demos. Snapshot import/export — share captured sessions as JSON files with teammates. Works with MV3 — built on Manifest V3, no deprecated background pages, no persistent background processes. Who it's for Frontend developers who need to test edge cases (errors, empty states, slow responses) without coordinating with a backend team, and QA engineers who want to reproduce exact API conditions reliably across machines.