I built Mockphine to stop frontend teams from waiting on unstable APIs

I kept running into the same problem across projects: frontend and QA work gets blocked because backend endpoints are incomplete, unstable, or constantly changing in shared staging.

Most teams do one of two things:

over-mock everything and lose confidence in real behavior, or
wait for backend/staging and lose delivery speed.

So I built Mockphine: a local mock API server that lets you mix both approaches route-by-route.

What it does:

Set each endpoint to Mock, Passthrough, or Disabled
Choose unmatched-route behavior: strict 404 or passthrough
See every request in Live View with served-by source, status, duration, headers, and body
Simulate delay/failure to test real UI edge cases

Who it’s for:

Frontend engineers
QA engineers
Small teams shipping API-heavy apps quickly

Business model:

7-day full trial
One-time license (pay once, no subscription)

I’m building this in public and looking for blunt feedback from teams doing real integration work.

Two questions:

What is the most painful part of your current mock + staging workflow?
If you tried a tool like this, what would make you trust it in your release process?

If you want to check it out: https://mockphine.com/

If you want, I can also write a second Indie Hackers version that is more “story/personal journey” and less feature-focused (usually better for comments).