Mike Hall

Took ownership of improving correctness, performance, and security for high-stakes assessment workflows. Focused on eliminating calculation errors, hardening response integrity, and defining safe integration boundaries for embedded client applications while improving database performance under load.

• Diagnosed and eliminated assessment calculation errors by analyzing and optimizing critical PostgreSQL queries using EXPLAIN ANALYZE and query planning tools, improving accuracy and response times.
• Implemented JWT-based response verification to prevent tampering and enforce once-only processing of assessment submissions, strengthening trust in platform outcomes.
• Designed and built a secure cross-origin communication API to support embedded client applications, establishing explicit trust boundaries between host and embedded contexts.
• Reduced operational risk by identifying and resolving performance bottlenecks affecting high-concurrency assessment workflows.
• Improved delivery reliability by introducing lightweight team practices that clarified acceptance criteria and reduced rework in high-impact assessment workflow changes.

Skills: Backend System Architecture, Data Integrity and Correctness, Secure API Design, Trust Boundary Definition, Database Performance Optimization, PostgreSQL, JWT Authentication, Ruby, Ruby on Rails, JavaScript, Observability and Logging