Kostiantyn Nesterenko nesterenko-kv

Kostiantyn Nesterenko

Senior Backend Engineer · C# / .NET · Distributed Systems

Building reliable, observable, and performance-oriented backend systems.

About me

Backend engineer with 8+ years of experience designing and maintaining production systems with C# and .NET.

I focus on high-load and distributed systems, asynchronous programming, real-time communication, performance engineering, resilient integrations, observability, and production reliability.

Current focus

Building production services with .NET 10 and ASP.NET Core
Designing WebSocket and streaming infrastructure
Improving graceful shutdown and background-worker lifecycle ownership
Profiling memory usage, GC pressure, contention, and hot paths
Applying OpenTelemetry, Prometheus, Grafana, Elasticsearch, and Sentry
Using AI-assisted engineering for implementation, review, and regression analysis

Featured projects

Tailbook

A modular-monolith and monorepo platform for grooming-salon operations.

Highlights

.NET 10 backend
ASP.NET Core and EF Core
Modular bounded contexts
Outbox-based infrastructure
Multiple web applications
Redis and PostgreSQL
Docker Compose environments
CI, coverage, and container scanning
ADRs and operational runbooks

Geohash.NET

A lightweight, performance-oriented C# library for encoding and decoding string and integer geohashes.

Highlights

String and 64-bit geohashes
Bit interleaving and base32 encoding
Prefix-based spatial indexing
BenchmarkDotNet analysis
Low-allocation implementation
Detailed algorithm documentation

Technology stack

Backend

C# · .NET · ASP.NET Core · Minimal APIs · REST · gRPC
WebSockets · SignalR · EF Core · Dapper · SQL Server
PostgreSQL · MySQL · Redis · ClickHouse · RabbitMQ

Infrastructure and observability

Docker · Kubernetes · GitHub Actions · GitLab CI
OpenTelemetry · Prometheus · Grafana · Elasticsearch · Sentry

Engineering principles

Measure before optimizing.
Make ownership explicit.
Treat cancellation as part of the contract.
Prefer deterministic regression tests for concurrency bugs.
Keep abstractions only when they remove real complexity.
Production behavior matters more than architectural diagrams.

Areas I enjoy working on

public sealed record EngineeringInterests(
    bool DistributedSystems = true,
    bool HighLoadBackends = true,
    bool AsyncAndConcurrency = true,
    bool PerformanceEngineering = true,
    bool StreamingAndWebSockets = true,
    bool Observability = true,
    bool ProductionReliability = true);

GitHub activity

Backend systems should be fast, observable, predictable, and boring to operate.

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