Question 4Integrations and APIs
When would you build a custom integration, and when would you push for a product feature?
Senior FDEs turn repeated customer work into product. They want to hear how you decide.
“Hands-on with APIs, webhooks, authentication (OAuth, SSO) and data integrations”Forward Deployed Engineer · Harmony
The answerFour steps
- 1
Custom first, to unblock the customer and learn
Say it like this
“When a customer is blocked, I build it custom, say a Salesforce sync in two weeks, because they're paying now and I learn what they need.”
Why it scores
Unblocks the customer first. Custom work is how you learn what to build.
- 2
Track how often the same need shows up across customers
Say it like this
“But I keep a simple log: every custom piece, which customer, how many days.”
Why it scores
Tracks repeats with data. Without the log, it's anecdotes.
- 3
Bring the product team a short write-up with real usage and effort saved
Say it like this
“I write the product team one page: three customers, 25 engineer-days spent, and what a general version would need.”
Why it scores
Brings evidence in their terms: customers, effort, scope.
- 4
Help build the general version and move customers onto it
Say it like this
“Then I offer to pair with them on the build and move my three customers onto it, so we stop maintaining three copies.”
Why it scores
Finishes the job. Moving customers over is what retires the custom copies.
StrongAll together
About a minute, out loud. The marked parts are the four steps; hover one to find it above.
When a customer is blocked, I build it custom, say a Salesforce sync in two weeks, because they're paying now and I learn what they need.1 But I keep a simple log: every custom piece, which customer, how many days.2 When the same sync shows up for a third customer, I write the product team one page: three customers, 25 engineer-days spent, and what a general version would need.3 Product teams move on numbers like that. Then I offer to pair with them on the build and move my three customers onto it, so we stop maintaining three copies.4
WeakThe answer that fails
Sounds fine. Common. Scores low.
“I'd build custom when the need is specific to one customer, and push for a feature when many customers need it. I'd raise it with the product team in our next sync.”
Interviewer's note
True but empty. No rule for “many,” no evidence, and the custom copies live on forever.
PracticeTwo minutes, then they push back
Your turn
When would you build a custom integration, and when would you push for a product feature?
Answer like you're in the room: about two minutes, no notes. Say it out loud, even alone. It feels different from thinking it. Then check your answer against what interviewers score.