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)
Java Testcontainers Integration Tests
How to use Testcontainers in JUnit5 to spin up real Postgres, Redis, and Kafka containers for...
Mock Network Requests with MSW
How to use Mock Service Worker (MSW) to intercept network requests in JavaScript tests and...
Test Express APIs with supertest
How to test Express.js REST API endpoints end-to-end using supertest, including status codes, JSON...
Property-Based Testing with Hypothesis
How to use Hypothesis for property-based testing in Python, generating hundreds of test cases...
Mock External APIs with responses Library
How to mock HTTP API calls in Python tests using the responses library, including status codes,...
Pytest Fixtures and Parametrize
How to use pytest fixtures and @pytest.mark.parametrize to write data-driven tests with reusable...
Ambassador: Offload Cross-Cutting Concerns to a Proxy
How to offload cross-cutting concerns to a proxy ambassador. Covers connection pooling, retry...
Anti-Corruption Layer: Isolate Legacy with Adapters
How to isolate legacy systems with translation adapters. Covers ACL facade, domain translation,...
Backends for Frontends: Dedicated Backend per Client Type
How to create dedicated backends per client type. Covers BFF for web, mobile, and desktop. Covers...
Modular Monolith: Single Deployable with Module Boundaries
How to build a modular monolith with strict internal module boundaries. Covers module isolation,...
Sidecar Pattern: Extend Services with Companion Containers
How to extend services with companion containers for cross-cutting concerns. Covers sidecar...
Strangler Fig: Gradually Replace Legacy by Intercepting
How to gradually replace a legacy system by intercepting routes and routing traffic to new...
Batch-to-Streaming Bridge
How to bridge batch and streaming pipelines with a data lake. Covers Lambda architecture, Kafka...
CDC Pattern: Stream Database Changes to Downstream
How to stream database changes to downstream consumers with CDC. Covers log-based CDC, Debezium,...
Data Lineage Tracking: Track Origin End-to-End
How to track data origin and transformations end-to-end. Covers column-level lineage, OpenLineage,...
ETL Extract-Transform-Load
How to build ETL pipelines with extract, transform, and load stages. Covers staging tables,...
Idempotent Load: Re-run Data Loads Safely Without Duplicates
How to re-run data loads safely without duplicates. Covers deduplication keys, MERGE upserts, load...
Schema Registry Evolution
How to manage schema versions for streaming pipelines with a schema registry. Covers Avro, backward...
Container-Presenter: Separate Data Logic from Rendering
How to separate data-fetching logic from rendering in React using the container-presenter pattern....
Custom Hook Composition
How to compose reusable logic with custom React hooks. Covers hook composition patterns, dependency...
Optimistic Update: Update UI Immediately, Reconcile on
How to update UI immediately and reconcile on server response in React. Covers rollback on error,...
Progressive Enhancement
How to build a functional HTML baseline and progressively enhance with JavaScript. Covers core...
State Machine UI: Finite State Machines for UI
How to model UI state transitions with finite state machines in React. Covers XState, statecharts,...
Suspense Boundary: Declarative Loading States with React
How to use React Suspense boundaries for declarative loading states. Covers data fetching,...