Harbor Health frontend interview

Frontend engineer interview at Harbor Health; Maya showed measurable frontend performance work and contract-testing experience relevant to the product. The coding exercise exposed a gap on back-to-back appointment boundaries, corrected after a prompt; her disagreement example also lacked a clear account of her own actions. Her evidence merits follow-up on availability handling and ownership.

Scores

• Coding correctness — 3/5 — initially treated back-to-back appointments as overlapping; corrected after the interviewer’s example.
• Problem framing — 3/5 — asked about time zones and raised invalid requested intervals, but did not initially clarify endpoint inclusivity.
• Behavioral ownership — 2/5 — described API instability and raising it in standup, but gave no specific resolution she drove.
• Relevant technical experience — 4/5 — concrete performance results and contract-test outcomes; both claims rest on her account.
• Communication — 3/5 — explained her technical approach clearly, but the disagreement example remained general after follow-up.

Doubts and how to resolve them

Promises

Evidence

Coding correctness

• After a prompt — When asked to walk through a 9:00–9:30 booking followed by 9:30–10:00, Maya noticed her <= / >= comparisons would reject the adjacent slot, called that wrong, and changed them to strict comparisons. The adjacent-slot case was specifically relevant to the stated “looks free but can’t be booked” complaint.

Problem framing

• After a prompt — After receiving the canBook exercise, Maya asked whether times were in the clinic’s timezone or UTC; Lucia specified clinic-timezone Date objects.
• After a prompt — Given the appointment-overlap task, Maya proposed checking whether the requested start is before the existing end and the requested end is after the existing start, then using some to reject a booking when any appointment overlaps.
• On own — While discussing what else could go wrong, she raised rejecting a requested end before its start and noted an empty appointment list would return true with some.
• After a prompt — When Lucia asked about a provider’s 10-minute cleaning buffer, Maya proposed extending each existing appointment’s end before comparing and asked whether the buffer was per clinic. Lucia clarified it was per provider.

Behavioral ownership

• After a prompt — Asked for an example of disagreement, Maya described Copperleaf’s backend team changing the policies API each sprint, including renamed fields and fields becoming optional; pages broke, and she said the situation eventually improved.
• After a prompt — When Ben asked what she did, Maya said she raised it in standup a few times and that the team discussed it; she did not identify a specific action or result she personally drove.
• After a prompt — Asked how things ended with the person she disagreed with, Maya said they got along and it was not a major fight.

Relevant technical experience

• On own — In her opening example, Maya said she virtualized a 4,000-row reports table and split chart code into an on-demand bundle over two sprints; load time fell from 6.2 to 1.8 seconds, and “page frozen” tickets stopped. She said she did this without a ticket; the account was not probed.
• After a prompt — Asked how to catch API changes before users encountered them, Maya said she wrote contract tests against Copperleaf’s OpenAPI file; the build failed when a used field was renamed or made optional. She reported zero breakages for about three months and said the backend lead adopted the setup for two other teams. This account was not probed further.

Communication

• On own — Before starting the exercise, Maya asked a focused clarification about the time-zone basis for the dates.
• After a prompt — In response to the testing question, she offered contract tests as an approach and contrasted them with end-to-end tests, which she said are slow.

The candidate

• Maya is a frontend engineer at Copperleaf, where she has worked for about two years on a portal for insurance agents using policies and quotes.
• Reports-page performance work and contract tests are described under Evidence.
• She did not discuss why she is moving, compensation, location, notice period, start date, or other interview processes.

Her questions

• How often do double bookings happen, and does the frontend or backend let them through? — Lucia said there are a few dozen a week across roughly 300 clinics, mostly due to two front-desk staff booking the same slot at once; the backend needs a lock, while stale frontend availability makes the problem worse.
• What would the first project be? — Ben said it would probably be the availability view, making sure the front desk sees fresh information.
• How is the team split between frontend and backend? — Ben said there are six engineers, two frontend-leaning; Maya would be the third.
• → Lead follow-up with the availability view and how it can show fresh information while the backend handles booking races.