Tell me about a project where you had to move fast and make quick technical decisions. How did you balance speed with quality?

Situation: Meta acquired a startup whose product we needed to integrate within 8 weeks before a competitor could launch a similar feature. The integration involved connecting their recommendation API with our content platform, which normally would be a 4-month project. Task: As the lead engineer on the integration, I needed to deliver a working integration that was production-ready in half the normal timeline while not creating technical debt that would slow us down later. Action: I made three key decisions to balance speed and quality. First, I identified the critical path — the 3 features that mattered for launch — and deferred 7 nice-to-have features. Second, I established "quality gates" that we would not compromise on: test coverage for the integration layer, error handling for the API boundary, and rollback capability. Everything else was negotiable. Third, I used feature flags to ship incrementally — we could release to 1% of users, validate, then ramp up. This let us move fast without risking the entire user base. Result: We launched in 7 weeks with the 3 core features. Zero critical incidents at launch. The feature flags let us catch and fix two edge cases at 5% rollout that would have been major issues at full scale. We delivered the deferred features over the next 6 weeks, and the codebase was clean enough that the second phase moved faster than projected.