Capture real requests
Record only API traffic from the active tab.
fetch/XHRAPI capture
3 modesStatic / Merge / Dynamic
scenariosgrouped states
Scenario testing
Test every API state from the browser.
Capture real fetch/XHR requests, turn them into mocks, then switch success, empty, slow, and error states locally.
Create from one hit
Turn a captured request into a rule with URL, method, headers, and body filled in.
Choose response mode
Use Static, Merge, or Dynamic responses for different testing needs.
Switch scenarios fast
Group rules into states like empty cart, payment failed, or slow inventory.
Product screens
Cyberpunk pixel UI, built for real debugging.
Capture requests, edit mock rules, and confirm active mocks directly on the page.
Captured APIs
Capture panel
Response modes
Rule editor
Mock feedback
Page badge
FAQ
Fast answers before you install.
The short version: it runs locally, focuses on API traffic, and keeps mock states easy to switch.
How do I install the Chrome extension?
Download the latest release zip, unzip it, open chrome://extensions, enable Developer mode, and load the unzipped folder.
How do I add a mock rule?
Paste a cURL command into the Add flow, or capture a real fetch/XHR request and turn it into a rule with Mock this.
What response modes are supported?
Use Static for fixed responses, Merge to patch real API data, or Dynamic to compute a response from the request and real response.
Can I move rules between projects or teammates?
Yes. Export rules as JSON, import them later, or keep scenario groups for repeatable local testing.
JSON rules in, JSON rules out
Mock the edge case. Ship the interface.
Import and export rule sets, group scenarios, and keep your frontend work moving even when the API is not ready to cooperate.
Runs locally in Chrome. No proxy server required.