MockMate

APIs go down. You keep going.

MockMate is a Chrome extension for developers and QA who need reliable API behavior without running a full backend every time. Switch between Real, Record, and Replay so the same app can talk to live services or to saved responses you control. What you can do Real mode — Normal browsing; no interception for mocks (when you want the live API). Record mode — Capture responses as you use the site, per endpoint, so you build a faithful snapshot of real traffic. Replay mode — Serve your saved responses instead of the network, with per-endpoint toggles so you can mix real and mocked calls. Edit mocks — Adjust status codes, headers, and body to reproduce errors, edge cases, or contract changes before the server exists. Sessions — Organize work with drafts and named sessions so scenarios stay repeatable across tabs and days. Replay delay — Add a global delay (up to 60 seconds) to simulate slow networks or timeouts. Quick setup — Add endpoints from captured traffic or paste a cURL command when you already know the request. Who it’s for Frontend engineers testing against APIs that are unstable, rate-limited, or not ready yet. Teams that want deterministic demos and regression checks without standing up mock servers. Anyone who prefers local, browser-side workflow over shared mock infrastructure. Privacy MockMate stores configuration and captured mock data locally in your browser (chrome.storage.local). It does not send your API traffic to MockMate servers for processing—your data stays on your machine. See the extension’s privacy policy for details. Get started Install MockMate, open your app, choose Record, use the site, then switch to Replay and refine responses as needed. Turn the extension off anytime with the global toggle.