MockFlow
Mock any API response in 3 clicks, right inside Chrome DevTools.
Return any status code, headers, body or delay for the page's own fetch and XHR calls.
No proxy, no mock server, no code changes. Your mock rules and intercepted traffic stay on your device.
Built for front-end developers
Build and test the UI before the backend is ready, and reproduce the edge cases that are hard to trigger for real.
Mock in 3 clicks
Pick a URL pattern (wildcard or regex), set the response, done. Matching requests never touch the network.
Errors & slow networks
One-click 400, 401, 404 and 500 responses, delays up to seconds, and fully offline requests.
Profiles per project
Group rules into profiles and switch between them. See every intercepted request live in the panel.
Local & private
Your mock rules and intercepted traffic stay on your device. No analytics or tracking. Paid plans only check your license key with Lemon Squeezy.
Simple pricing
Start free. Upgrade when you need more.
Free
$0
- ✓ 3 active mock rules
- ✓ 1 profile
- ✓ Any status code, body and delay
- ✓ Live request log
Pro
$8 / month
- ✓ Unlimited active rules
- ✓ Unlimited profiles
- ✓ Custom response headers
- ✓ Export & import rules
- ✓ Offline request simulation
- Cancel anytime
Founder Pass
$29 one-time
- ✓ All current Pro features, for life
- ✓ Free updates and improvements to those features
- ✓ No subscription for these features
- ✓ Use on up to 3 browsers
- Limited to the first 100 buyers
Future server-based features, such as team sharing and sync, are not included and may be offered separately.
Coming soonPrices in USD. Payments, taxes and receipts are handled by Lemon Squeezy, our Merchant of Record. Paid plans are delivered as a license key you paste into the extension.