#kotlin
4 posts filed under this tag.
Reading AG-UI as a wire protocol, not a framework
I kept rebuilding the same SSE envelope every time I wrote an agent UI. AG-UI is the first serious attempt I have seen at standardising that envelope. In this post I strip the protocol down to its wire shape and rebuild a minimal Spring WebFlux endpoint that speaks it without an SDK.
Actor-per-Entity vs Postgres Optimistic Locking: A Seat-Reservation Bake-off
I ran the same hot-key seat reservation workload two ways: Postgres with a version column and retries, and a single actor per seat. The actor design did not scale better — it moved the hard problem from concurrency control to routing and rebalance correctness, and that trade was the easier one to reason about under hot keys.
Event-Log-as-Source-of-Truth Turns Schema Evolution Into a Forever Problem
When the log is the source of truth, every schema change is permanent. A Kotlin/Avro walkthrough of the rename that passed the Schema Registry check and silently corrupted every old event, plus the Protobuf and Avro invariants I now keep pinned above my desk.
JetBrains Tracy: Pragmatic AI Observability for Kotlin
JetBrains Tracy is a Kotlin library that wires LLM-aware tracing into your app on top of OpenTelemetry. This post walks through how I integrated it in a Spring Boot service, the design decisions that matter, and the failure modes teams hit once LLM calls become the hottest path in their system.