Minsik Kim Technical Portfolio¶
PLATFORM SOFTWARE ENGINEER
Summary¶
I find and fix concurrency and data-correctness problems in platform backends, then verify the result with reproducible tests and real API and database behavior. I have applied this approach across full-time work on a code-generation platform and Rust services, an open-source SQL engine, and a mobile product that I operate directly.
Representative Work¶
ClumL · Outbound LLM API Rate-Limiting Concurrency Fix¶
Type and period: Full-time role · Mar 2025 - Jul 2026
Role: Rust backend problem analysis, implementation, and regression verification
Core change: I fixed a concurrency defect in which LLM API calls read the same pre-reservation state and passed together, pushing the in-flight call count and token reservations beyond their limits.
Validation: Under the same concurrency load, I reproduced over-reservation in which the in-flight call count and pending token reservations each reached at least ten times their respective limits, then confirmed that both stayed within their respective limits after the fix.
Technologies: Rust · concurrency control · regression testing
TmaxCloud · Pre-Deployment API Testing for a Code-Generation Platform¶
Type and period: Full-time role · Oct 2021 - Nov 2024
Role: Design, implementation, and verification of the React test UI, Java REST API, and database schema
Core change: I built a test UI for a platform that generates Java APIs, SQL, and a JAR from UI-defined services, so users can check API responses and database state before deployment.
Validation: Invalid service definitions, request/response shapes, and database-write errors could be found without repeating the roughly 20-minute build, deployment, and verification cycle.
Technologies: Java · WebSocket · Tibero
GlueSQL · Implementing DISTINCT Execution Semantics¶
Type and period: Open-source contribution · Jun 2021 - Present
Role: Direct implementation in a Rust SQL engine and contributor code review
Core change: I fixed SELECT DISTINCT returning duplicate results like a regular SELECT, implementing the appropriate deduplication for regular queries and aggregate functions.
Validation: Regression tests covered DISTINCT over single and multiple columns and aggregate functions including COUNT.
Technologies: Rust · parser/AST · SQL executor
Coupler · Mobile Dating App Engineering Lead¶
Type and period: Independent product · Jul 2024 - Present
Role: Engineering and operations lead across the React Native app, Express API, React admin web, and MySQL database
Core change: Made the app and admin web follow access state returned by the API instead of inferring review state independently.
Validation: I regression-tested the API response contract, mobile routing, and admin review queue to verify that server-side review state was reflected consistently in the app and admin queue.
Technologies: React Native · TypeScript · MySQL
More¶
See Engineering Principles for the shared approach to problem decomposition, decisions, and verification.