SOFTWARE ENGINEER

Daniel
Hajnos

I build robust systems and clean code. C#, Python, Go, SQL — whatever the problem needs.

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~/portfolio

$ whoami

Daniel Hajnos

$ cat skills.txt

C# · Python · Go · SQL · PostgreSQL

$ echo $STATUS

Available for work

$ _

C# — PYTHON — GO — SQL — POSTGRESQL — SYSTEMS ENGINEERING — C# — PYTHON — GO — SQL — POSTGRESQL — SYSTEMS ENGINEERING — C# — PYTHON — GO — SQL — POSTGRESQL — SYSTEMS ENGINEERING — C# — PYTHON — GO — SQL — POSTGRESQL — SYSTEMS ENGINEERING —

C#

.NET, ASP.NET Core, Entity Framework, LINQ, async/await patterns

.NET ASP.NET EF Core

🐍

Python

FastAPI, Django, scripting, data processing, automation

FastAPI Django Scripting

Go

Microservices, concurrent systems, CLI tools, API development

Goroutines gRPC CLI

SQL

Complex queries, stored procedures, query optimization, migrations

T-SQL PL/pgSQL Optimization

🐘

PostgreSQL

Database design, indexing, partitioning, replication, performance tuning

Design Indexing Replication

⚙

Infrastructure

Docker, CI/CD, cloud platforms, monitoring, deployment pipelines

Docker CI/CD Cloud

High-Performance API Service

ASP.NET Core microservice handling 10k+ requests/sec with PostgreSQL backend, Redis caching, and automated CI/CD pipeline.

C# ASP.NET Core PostgreSQL Redis

Data Pipeline & ETL Framework

Python-based ETL pipeline processing millions of records daily with automated error handling, monitoring, and PostgreSQL data warehousing.

Python FastAPI PostgreSQL Docker

Real-Time Event Processing

Go microservice for real-time event streaming and processing with goroutines, message queues, and PostgreSQL for persistence.

Go gRPC PostgreSQL Kafka

Database Migration Toolkit

Custom SQL migration framework with version control, rollback support, and automated schema comparison for PostgreSQL and SQL Server.

SQL PostgreSQL T-SQL Python

I'm a software engineer who enjoys building things that work — reliably, efficiently, and cleanly. I've spent years working across the stack, from writing SQL queries that need to be fast to designing Go services that need to be concurrent.

My toolkit is polyglot by necessity: C# for enterprise systems, Python for data and automation, Go for performance-critical services, and SQL/PostgreSQL for everything that involves data. I believe the best tool is the one that solves the problem without adding unnecessary complexity.

When I'm not coding, I'm thinking about code — architecture patterns, performance optimization, or how to make the next system a little bit better than the last one.

about.md

$ cat about.md

---

name: Daniel Hajnos

role: Software Engineer

focus: Systems & Data

---

> "Talk is cheap. Show me the code."

— Linus Torvalds

$ _

Have a project in mind? Want to collaborate? Or just want to talk tech? I'm always open to interesting conversations.

daniel@hajnos.com

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Daniel
Hajnos

Tech Stack

C#