Kyryll Pavlenko_

I work in Go and TypeScript on the unglamorous half of the stack — storage engines, event-driven services, locking, and AI plumbing. I care about systems that stay simple under load and prose that reads clean.

Right now I'm building Stylo, an AI copilot editor for writers, and Job-Agent, an AI-first job search platform. I write weekly about the ideas underneath that work.

Writing

• 2026Database Engine from Scratch
• 2026My First IT Interview Experience
• 2026Stack vs Heap: The Hidden Bottleneck of The Performance
• 2026Jack of all trades, master of all
• 2026Why Telegram Feels So Freaking Fast (And How You Can Steal Its Tricks)
• 2026Extremely fast LSM Trees
• 2026Write Buffering in System Design
• 2026Bloom Filter Search on Billion Rows
• 2026Concurrency vs Parallelism: Why Python Makes You Choose
• 2026Different RAG types you've never heard of
• 2026What Nobody Tells You About Claude Code: Harness and Loop Engineering, Implemented
• 2026How I build an AI job searching system?
• 2026Being smart is a curse
• 2026String Tokenization Problem
• 2026Everything you need to know about funding in the tech world
• 2026How I implemented locking in my E-commerce system

All writing →

Projects

• Stylo — an AI copilot editor for writers and content creators.
• Job-Agent (wip) — semantic CV-to-job matching with AI-written applications.
• E-Commerce-System (wip) — a Go commerce backend, load-tested and fully instrumented.
• Restaurant-System-Microservices — event-driven Go microservices over gRPC and GraphQL.
• OneTube — a video platform on Go, MinIO object storage and RabbitMQ workers.
• Lychee-Chat — real-time chat over WebSockets, Redis pub/sub and BullMQ.
• Personal-Finance-Tracker — a React SPA over a Python REST API.
• Eye-Tracking-Page-Scrolling — scroll any page with just your webcam, fully on-device.
• Security-Tools — Python utilities for everyday red-team tasks.
• ARP-MITM-Toolkit — an ARP-spoofing toolkit for authorized LAN testing.