Swift error handling interview questions

Error handling questions test whether you design for failure deliberately or bolt it on. Senior answers treat errors as part of the API contract.

What gets asked

Expect the mechanics of throws, do-catch, try, try?, and try!, plus when to use Result instead, and how errors propagate up a call stack. Interviewers may ask how you model domain errors as an enum, how you surface a failure to the UI, and how error handling interacts with async/await.

Designing good error APIs

Model errors as a meaningful enum so callers can switch on cases and recover appropriately, rather than throwing opaque strings. Fail at the boundary, translate low-level errors into domain terms, and decide deliberately what is recoverable versus fatal. In async code, thrown errors propagate through await just like synchronous throws.

Go deeper than a summary

Share Your Screen works topics like this through in full: 75 solved Swift problems with tests, 9 real case studies, and 7 annotated mock interviews, so you rehearse the live round instead of just reading about it.

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Frequently asked

throws or Result?

Use throws for straightforward synchronous propagation with try; use Result when you need to store, pass around, or defer handling an outcome, or bridge callback APIs.

How should errors reach the UI?

Translate them into user-meaningful states at the boundary, not raw system errors, so the view can show a clear message and a recovery action.