Kim Hyuntae (Ken)
Backend engineer who tracks down bottlenecks with metrics · Python · Java · Spring
A backend engineer who pins down bottlenecks with metrics through a measure-hypothesize-verify loop. I currently own search and response performance at Zimssa.
I moved search to AWS OpenSearch — 5.7M records unified at 135ms avg (312ms p95, 99.7% success) — and traced an N+1 bottleneck with Datadog APM, cutting response time from 6s to under 100ms.
I care about keeping systems cheap to change and worth trusting, and I invest in operational maturity like Testcontainers-based integration tests.
Before that, I spent four years building and running the backend of a 9M-MAU offline location platform (loplat) — delivering 1M FCM notifications in 5 seconds, tuning spatial indexes to 100ms, and more.
Backend Developer
Zimssa
Unified search over 5.7M records on AWS OpenSearch (135ms avg, 312ms p95, 99.7% success). Traced an N+1 bottleneck with Datadog APM and cut response time from 6s to under 100ms. Adopted Testcontainers for integration testing.
Backend Developer
loplat
Designed and ran the backend for a 9M-MAU offline location platform. Built a Pub/Sub + Cloud Functions pipeline delivering 1M FCM notifications in under 5 seconds (98%+ delivery), tuned spatial indexes for sub-100ms location lookups (powering a 1M-MAU iOS campaign), and improved LGU+ WPS positioning accuracy from 32.3m to 19.9m.
Backend Developer
DotDotDot
Backend development for 3D avatar metaverse chat application