MockFill: API Mocking

Intercept and mock HTTP APIs directly in your browser for frontend testing.

As of June 2026, MockFill: API Mocking has 26 users and a 5.00/5 rating from 1 reviews in the Developer Tools category.

Usersup 188.9 percent+188.9%
26
26
Ratingno change0%
5.00
1 reviews
Reviewsno change0%
1
Version
2.3.1
Manifest V3

History

7 snapshots

Tracking since Apr 8, 2026.

27.3617.57.640000000000001Apr 8, 2026Jun 4, 2026
View as table
DateUsersRatingReviewsVersion
Apr 8, 202695.0012.3.1
Apr 19, 2026115.0012.3.1
Apr 25, 2026185.0012.3.1
May 9, 2026205.0012.3.1
May 19, 2026215.0012.3.1
May 25, 2026225.0012.3.1
Jun 4, 2026255.0012.3.1
Now265.0012.3.1

Permissions & access

Permissions
storage
Host access
http://*/*, https://*/*

Screenshots

MockFill: API Mocking screenshot 1

About

Mock and intercept fetch/XHR APIs in your browser with rule-based responses, delays, headers, presets, and quick toggles.

MockFill: API Mocking is a developer-focused Chrome extension for mocking HTTP APIs directly in the browser.

Test frontend flows without touching backend code:
- Simulate success, empty, and error responses
- Test loading states with response delays
- Validate UI behavior for edge cases
- Work faster on localhost, staging, or any web app

What you can do:
- Intercept both `fetch` and `XMLHttpRequest` calls
- Match requests by URL pattern (string or regex) and HTTP method
- Configure custom response status, body, headers, and delay
- Enable/disable mocking globally or per rule
- Reorder rules to control matching priority
- Track hit counts for each mock rule
- Import/export mock rules as JSON
- Import from cURL to create rules quickly
- Save presets for different testing scenarios and switch instantly

Built for:
- Frontend developers
- QA engineers
- Teams testing API-dependent UI states

Why MockFill: API Mocking
- No backend changes required
- No external proxy setup
- Fast, repeatable API testing workflow inside Chrome

Privacy:
- Rules and settings are stored locally in your browser.
- No API payloads are sent to external servers by the extension.

Technical

Version
2.3.1
Manifest
V3
Size
1.81MiB
Min Chrome
90
Languages
1
Featured
No

Metadata

ID
ibdcndlmccmofmdkhflechalamaeobhh
Developer ID
u127dda5168caf73b1a8e0824e6754443
Developer Email
[email protected]
Created
Feb 22, 2026
Last Updated (Store)
Feb 23, 2026
Last Scraped
Jun 4, 2026
Website
mockfill.com

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Data sourced from the Chrome Web Store · last verified Jun 4, 2026.