Case study

StubLab

Product mentor

Intelligent API stubbing for faster delivery

2025 · MentorBridge · APIs · Developer Tools

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Screenshots

StubLab in the wild

StubLab landing — create and test APIs without a backend
Create and test APIs with StubLab

The choice

Wait for the backend — or fake the API and keep building?

Frontend and QA often sit idle until the real API is ready. I had to decide whether we would wait, or work against a shared fake API.

The easy option

Wait until databases and services are stable
Write one-off mocks that stop matching the real API
Find integration bugs at the end of the sprint

What I chose

A shared stub server so UI and QA can work while the backend is unfinished
Fake responses that look like the real API the team will ship
Analysts, frontend, backend, and UX all test against the same stubs

In short

If everyone agrees what the API will look like, do not wait for the database to start the next build.

What I checked first

Do the fakes match the real API?
Stubs should use the same shapes as production. Convenient fake data that lies will cost time later.
Can frontend and QA keep moving?
If the backend is incomplete, the rest of the team should still have something honest to build against.
Is switching to the real API easy?
When the live API arrives, it should be a config change — not a rewrite of the UI.

The problem

Frontend and integration work often blocks on backends that are incomplete, unstable, or still wired to heavy database dependencies. Teams lose days waiting for environments instead of iterating on contracts and UX.

Stubbing exists, but most setups are ad hoc — brittle mocks, undocumented responses, and little shared tooling across a squad.

What we built

StubLab is an intelligent stub server from the MentorBridge innovation lab (with SSMIET IIC): craft, configure, and test APIs without depending on a traditional database so development and QA can move in parallel.

I mentored the product direction and engineering craft — helping the team shape a tool that simulates API behavior quickly and keeps contracts honest between consumers and providers.

Approach

Stub-first workflows so UI and integration work is not gated on backend readiness.
Configurable responses that mirror real API shapes teams will ship.
Cross-functional delivery with analysts, frontend, backend, and UX in one loop.
Mentorship through reviews so early-career engineers own production-quality code.

Tools chosen

Node.js — a pragmatic stub runtime close to how APIs are consumed.
React — a clear surface for configuring and exercising stubs.
Contract-oriented stubbing — speed without losing fidelity to real endpoints.

Outcomes

Faster API iteration for MentorBridge product teams — and a concrete case study in shipping developer tooling under mentorship, from idea to a live product surface.