Codexworker

Custom API Development

I build REST/JSON APIs that are easy to use and safe to operate: clear contracts, validation, pagination, rate limiting, authentication and error handling from the start. In Go or PHP.

I'm a backend developer with 10+ years of experience across PHP, Go, MySQL and Elasticsearch. Recent work includes Cenoskop (30M+ products daily), Niftycent (US price intelligence), and facha.sk (Go backend). I build, fix and optimize backend systems that handle real data and real traffic.

What I Can Help With

Build REST/JSON APIs and backends.

Typical Problems

new API endpoints needed internal service APIs third-party integrations authentication and rate limiting pagination and validation

Relevant Experience

Built production APIs for Cenoskop (product search and comparison), facha.sk (job marketplace REST API) and Paidshield (encrypted messaging API). Authentication, rate limiting, pagination and error handling from day one.

What Is Included

API design
implementation (Go/PHP)
validation and error handling
auth/rate-limiting
pagination
OpenAPI documentation

How It Works

We agree on the API contract, build endpoints incrementally, and hand over documented, tested code. From €1,000 for a typical API.

Starting from €1,000

Typical small-to-medium API. Complex scope is estimated after a quick discovery call.

Frequently Asked Questions

Go or PHP for my API?

Depends on your existing stack and throughput needs. Go for high-throughput/low-latency, PHP/Symfony if you need to reuse existing code and models.

Related Services

Other problems I help with.

PHP Backend Development

Build or extend backend features, APIs and services in PHP.

Details →

Go Backend Development

Build backend APIs, services and daemons in Go.

Details →

Dockerized Backend Development

Containerize and Dockerize backend systems.

Details →

Backend Migration Without Rebuilding Everything

Migrate backend components incrementally.

Details →

Systems I've Built

Relevant production work.

Job & Services Marketplace

facha.sk

Find a job or offer your services.

Built the Go backend — API, matching logic and deployment.

Job Marketplace Services Go
Secure Communication

Paidshield

Chat application with end-to-end encryption.

Built the backend and encryption layer for a secure chat application.

End-to-End Encryption Real-time Communication Security
Security Scanner

remotedaemon.com

Remote security scanner with ping and certificate checking.

Built the scanning daemon and monitoring backend.

Security Ping Certificate
DNS Security

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.

DNS Security Privacy
Traffic Analysis

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.

Performance Optimization Data Collection

Need Help With This?

Describe the problem in a few lines — I'll look at it and tell you what I think.

Discuss an API project