Mathias Paulenko
Software Engineer & Founder of StackPractices
Mathias Paulenko
Software Engineer
Software engineer with 12+ years of experience building production systems across Python, JavaScript, React, and DevOps. I have contributed to enterprise projects spanning CI/CD pipelines, API design, cloud infrastructure, and full-stack development.
StackPractices is my personal project, born from a simple belief: great documentation should be copy-paste ready. Every recipe, pattern, and guide on this site is designed to save you time and help you ship faster.
Published Works (1032)
Clean Architecture
A practical guide to Uncle Bob's Clean Architecture: organize code into layers so that frameworks,...
How to Hash Passwords Securely (Python, JavaScript, Java)
Learn how to hash and verify passwords with bcrypt, Argon2, and PBKDF2. Practical examples in...
Convert CSV to JSON
Turn CSV files into structured JSON using Python, JavaScript, and Java. Pick the right library for...
Deep Clone in JavaScript: structuredClone vs lodash vs JSON
Compare deep clone methods in JavaScript, Python and Java. Create independent copies of objects and...
How to Use Elasticsearch Aggregations (With Examples)
Use Elasticsearch aggregations for faceted search, metrics, and time-series analytics. Step-by-step...
Distribute Background Tasks with Python Celery and Redis
Set up Celery with Redis broker for distributed task processing including task chaining, groups,...
Build a RabbitMQ Consumer with Python and Pika
Create a RabbitMQ consumer and producer in Python using pika with durable queues, work dispatching,...
Task Queues and RPC with RabbitMQ and AMQP
Distribute background tasks and implement request-reply patterns with RabbitMQ using durable...
Partial Class Pattern
Split a single class across two or more files so generated and hand-written code can coexist...
Fine-Tune a Language Model for Code Generation
How to fine-tune an LLM for code using LoRA and QLoRA on consumer GPUs.
Go REST API with Gin and Middleware
Build production-ready REST APIs in Go using the Gin framework with custom middleware for logging,...
Generate PDF Reports in Python: ReportLab & fpdf2 Guide
Create styled PDF documents from data using ReportLab and fpdf2 in Python.
Modular Monolith: Module Boundaries, Shared Kernel
Design a modular monolith with clear module boundaries, a shared kernel, dependency rules, and a...
Sentiment Analysis with Python and NLTK
Score text sentiment using NLTK VADER and custom lexicons in Python. Classify reviews, process...
asyncio.Semaphore: Limit Concurrent API Calls in Python
Use asyncio.Semaphore in Python to cap concurrent API calls, database queries, and resource access...
Flatten and Unflatten Nested Objects
How to convert nested objects to flat key-value pairs and back again, with dot-notation, bracket...
Parse CSV Files with Python and Pandas
How to read, filter, and transform large CSV files efficiently using Python pandas and the csv...
Parse Server Log Files with Python, Java and JavaScript
Parse and analyze server log files with Python, Java, and JavaScript. Covers regex, structured...
URL Encoding
Encode and decode URLs, query parameters, and path segments safely across Python, JavaScript, and...
Handle Database Deadlocks and Retries
Detect, prevent, and recover from database deadlocks with automatic retry logic, consistent lock...
Set Up Database Read Replicas for Scaling
Scale read-heavy workloads with database read replicas, replication lag monitoring, and read/write...
Build Responsive Email Templates with MJML
Create cross-client responsive email templates with MJML, compile them with TypeScript, inject live...
OpenAI Assistants API Chatbot: Build, Cost & Deploy
How to create an AI chatbot using the OpenAI Assistants API with function calling and file search.
OpenAPI 3.1 API Docs with Swagger UI and Redoc
A practical guide to documenting REST APIs with OpenAPI. Generate interactive Swagger UI and Redoc...