Backend development and diagnosis
I diagnose and fix backends that already run in production.
What I work on
PHP and Go, MySQL/MariaDB, Elasticsearch, Linux, Docker. Slow queries and endpoints, PHP processes eating CPU or RAM, stuck workers, crawling and ETL, Elasticsearch that can't keep up, legacy PHP migrations. I occasionally build something new — a Go worker, an API, a pipeline — but most of the work is on systems that already run.
What's actually broken
You don't know where the problem is. Send what you have — code, logs, metrics, EXPLAIN output, config. I'll look at it and write up what the bug is and what changing it would take.
Slow PHP Application? I'll Find the Bottleneck
Diagnose why a PHP application is slow, no rewrite required.
PHP Memory Leak Investigation
Find what causes PHP memory usage to grow until the process dies.
Why Is PHP Using So Much CPU?
Find what drives high CPU in PHP production.
Backend Performance Audit
Find and prioritize the real bottlenecks across your full backend stack.
Technical Debt Audit for Backend Systems
Assess technical debt in an existing backend.
Slow backend
Slow pages and queries, CPU or RAM at the ceiling, workers that can't keep up. I look for the cause first.
PHP Performance Optimization
Profile and optimize PHP applications that are slow, memory-heavy or consuming too much CPU.
MySQL Performance Optimization
Optimize MySQL queries, indexes and schema for a production workload.
MySQL Database Optimization
Optimize MySQL queries, indexes and schema for your workload.
Web Application Performance Optimization
Optimize the full request path for a slow web application.
Elasticsearch Performance Tuning
Tune Elasticsearch for your specific query and data patterns.
Elasticsearch Optimization
Optimize Elasticsearch queries, mappings, indices and cluster configuration.
Crawlers and pipelines
Crawlers, ETL, Elasticsearch indexing, aggregations, scheduled jobs. Millions of records.
Large-Scale Web Crawling
Scale crawling to millions of URLs across many hosts.
Large-Scale Web Crawler Development
Build scalable web crawling infrastructure.
Custom Web Scraping Development
Build custom web scrapers that run reliably.
Custom Data Pipeline Development
Build ETL/import/transform/export pipelines for large datasets.
Custom Price Monitoring Systems
Build price monitoring infrastructure for products/sellers.
Product Data Extraction
Extract and normalize product data from external sources.
Custom Elasticsearch Development
Implement Elasticsearch for search, analytics and indexing.
PHP and Go
I change existing PHP — fixes, performance, modifications. When PHP isn't the right tool for a piece, I rewrite that piece in Go.
PHP Developer for Existing Projects
Work on an existing PHP project — extensions, fixes and maintenance.
PHP Backend Development
Build or extend backend features, APIs and services in PHP.
Custom Go Daemons and Background Services
Build Go daemons and background services.
Dockerized Backend Development
Containerize and Dockerize backend systems.
Senior Backend Consulting
Architecture review, code review and problem-solving consulting.
Old PHP code
Old PHP applications with no documentation. Migrations, database problems.
Modernize Your Legacy PHP Application
Gradually modernize a legacy PHP application.
Backend Migration Without Rebuilding Everything
Migrate backend components incrementally.
Elasticsearch Migration & Upgrade
Migrate to or upgrade Elasticsearch with minimal downtime.
How It Works
Write what's happening
A few sentences. What's happening, when it started, what you've tried.
I look at the system
Code, logs, metrics, config. Whatever exists.
I write up what I found
What the bug is and what the fix would cost.
I fix it
Within the agreed scope.
Pricing
Diagnosis first, then a fixed price. Diagnosis has a fixed scope and a fixed price. I quote implementation once I know what it involves.
Systems I've Built and Run
A few of the production systems behind these services.
Cenoskop / Levnobot
Crawler monitoring millions of products. Processing 30M products daily and comparing them.
Built and maintain the full crawling pipeline — from scraping through Elasticsearch indexing to price comparison.
Niftycent
Price intelligence engine for the US market. Processing large-scale product data.
Built the data pipeline and crawling infrastructure for large-scale US product monitoring.
AnalyticsForWebsite
Custom solution for collecting and evaluating traffic metrics with emphasis on processing speed and minimizing backend load.
Designed and built the backend for fast traffic metric collection and evaluation.
Paidshield
Chat application with end-to-end encryption.
Built the backend and encryption layer for a secure chat application.
Synopsee
A Cleaner, Safer Internet. Take control of your DNS. Block ads, trackers, and malicious sites with customizable profiles.
Built the DNS resolution backend and profile management system.
facha.sk
Find a job or offer your services.
Built the Go backend — API, matching logic and deployment.
remotedaemon.com
Remote security scanner with ping and certificate checking.
Built the scanning daemon and monitoring backend.
About me
Backend work for more than 10 years — PHP, Go, MySQL, Elasticsearch, Linux, Docker. I work alone.
Contact
Write a few lines and attach whatever you have. I'll tell you what I think.
Write: what's happening · error message · log or metric · stack · URL.