Blink Health·Software Engineer·Onsite - System Design / Architecture
May 2026
System design round at Blink Health where I had to write a full approach doc and AI execution plan for a duplicate patient detection system. Pretty deep cut for a software engineer interview, felt more like a staff-level architecture exercise than anything I'd prepped for.
- Which patient attributes would you use to detect duplicate records, and why does each one matter?
- How would you score and rank confidence in potential duplicate matches? Walk through your approach to deterministic vs probabilistic matching, blocking, fuzzy string similarity, and weighted attribute scoring.
- How would you minimize false positives in the duplicate detection system, and what role does human review play?
- How does your system handle fuzzy or ambiguous situations like typos, missing fields, and address variations?
- What should the system do when its confidence in a match is low?
- How would you decompose this plan into tasks for an AI coding assistant, including prompts, quality gates, and verification steps?
“I started with the obvious ones: name, date of birth, SSN, MRN.”