I’m a Senior Software Engineer & Solutions Architect with a passion for backend development, especially in Java, Python and Spring Framework. 20+ years of experience in software development, solution architecture, and system design. I have a keen interest in web technologies, architecture patterns, and a curiosity for exploring new software development paradigms.

• 💡 I’m always learning about Java, Python, design patterns, and best practices in REST APIs.
• 🏗️ I design and document software architectures, from microservices to enterprise systems.
• 🤖 I work with spec-driven development and AI agentic development, building AI agents, skills and MCP integrations.
• 🖥️ All of my projects are available at my GitHub repos.
• 💬 Ask me about Java, Python, Solution Architecture, System Design, REST APIs, Microservices, and ADRs.
• 📫 How to find me: reach out on my LinkedIn page
• 🤝 I’m frequently looking to collaborate on interesting projects, especially Java and Python based.
• 🌐 I speak English 🇬🇧, Portuguese 🇧🇷, French 🇫🇷, some Spanish 🇪🇸, and a bit of Dutch 🇳🇱, feel free to reach out.

• Backend Development: Java, Python, Spring Boot/Security/MVC, Maven, Gradle, Hibernate, REST APIs, gRPC, SOAP/WSDL, Microservices
• Web Technologies: HTML5, CSS, JavaScript, Angular, React, JSON, XML, YAML, TOML, GraphQL, OpenAPI/Swagger
• Databases: Oracle, PostgreSQL, MySQL, SQLServer, MariaDB, H2 DB, SQLite, MongoDB, Redis, Cassandra
• Testing: JUnit, Pytest, Selenium, Playwright, JMeter, SonarQube
• Security: OAuth2, JWT, Spring Security, SSL/TLS, mTLS
• Cloud & DevOps: Azure, Docker, Kubernetes, OpenShift, CI/CD, GitHub Actions, Jenkins, Nginx, Kafka, Tomcat, JBoss, Prometheus, Grafana, SonarQube, Bitbucket
• Build & Dependencies: Maven, Gradle, Poetry, pip, uv
• Architecture & Modeling: PlantUML, Mermaid, Draw.io, Enterprise Architect, ArchiMate, Visio, ADRs
• IDEs & Editors: IntelliJ IDEA, VS Code, Vim, PyCharm, Cursor, Windsurf
• AI & LLM Tools: Claude, GitHub Copilot, ChatGPT, Gemini, Windsurf, Cursor, Codex, Ollama, LangChain
• AI Engineering: Spec-Driven Development, AI Agentic Development, AI Agents & Skills, MCP (Model Context Protocol), Prompt Engineering
• Agile & Practices: Scrum, Kanban, Sprint Planning, Backlog Refinement, Story Mapping, Retrospectives, Story Points
• Project & Collaboration: Jira, Confluence, Azure DevOps, Miro, Trello, Bitbucket
• Others: UML, OO, Design Patterns, Software Architecture, System Design, Bash/Shell Scripting

• SCJP - Sun Certified Java Programmer (Sun Microsystems)

• Distributed Batch Orchestrator - Distributed batch processing with Java 21, Spring Boot 3.4 and Spring Batch: six identical instances process banking reports together, with dynamic Master election per run and a live HTML/JS frontend visualizing the whole cluster.
• Report Composer POC — Spring Batch + Kafka + K8s - Distributed report composer generating reports using Spring Batch Remote Partitioning over Apache Kafka on Kubernetes with autoscaling.
• Flyway vs Liquibase — DB Migrations Compared - Side-by-side comparison of the two leading Java database migration tools, with working Spring Boot 3.4 setups for both Flyway and Liquibase on the same schema.
• GZIP Alternatives Benchmark - Compression and decompression benchmarks in Java comparing GZIP against modern alternatives, measuring speed and compression ratio trade-offs.
• Banking IBAN Generator & Validator - IBAN generation and validation service built with Spring Boot and Java 21, covering multiple country formats with full JUnit 5 test coverage.
• Banking Statement Converter Platform — CAMT / MT - Enterprise-grade platform converting internal domain data to MT940, MT942, camt.052, camt.053 banking file formats using Prowide Core + ISO 20022, Spring Batch and the Strategy Pattern.
• Banking Fixed-Length File Generator & Parser - Generates, parses and benchmarks CODA and SWIFT MT940 fixed-length banking files using 7 Java formatter libraries orchestrated via Spring Batch and the Strategy Pattern. Includes a React/Vite frontend.
• K8s Batch Processor - Spring Batch jobs on Kubernetes with Horizontal Pod Autoscaling (HPA) and real-time Server-Sent Events (SSE) progress tracking. Production-ready K8s manifests included.
• Automated Real Estate Monitor — Belgium - Daily scraping of Belgian property websites, detects new listings matching configurable criteria and sends email alerts. Python 3.12+, uv, SQLite.
• Resilience4J Demo — Fault Tolerance Patterns - Six fault-tolerance patterns (Circuit Breaker, Retry, Rate Limiter, Bulkhead, Time Limiter, Cache) in a single Spring Boot 3.5 project with real-world HTTP client scenarios.
• Schemas Demo: Avro vs Protobuf vs JSON Schema - Hands-on comparison of three data serialization formats with working FastAPI endpoints, showing how each works in practice, not just in theory.
• AI Agents & Skills for Software Engineering - A comprehensive system of 10 specialized AI agents with 95+ skills covering software engineering, system architecture, infrastructure automation, and project management.
• Contract-First Integrations - Reference implementation for contract-first (API-first) development using OpenAPI 3.0, Apache Kafka with Avro + Schema Registry, Flyway migrations and Spring Boot.
• Fake Data with Spring Boot & Quarkus - Generating realistic fake data in Java with Spring Boot, Quarkus, DataFaker and EasyRandom for testing and development.
• Flashcards App - PythonAnywhere - A simple flash cards web app based on a "question;answer" CSV list. Try it live at wallacese.pythonanywhere.com.
• Secure Password Hashing in Java - Secure password hashing in Java using BCrypt, Argon2 and PBKDF2 with salting and computational intensity for better application security.
• More projects on my GitHub repositories.

• [Medium] Markdown Is Becoming the Language of Software Engineering in the AI Era - The full story of Markdown's rise from a lightweight formatting syntax to the backbone of modern engineering workflows, documentation and AI tooling.
• [Dev Community] Markdown: The New Programming Language? Exploring Spec-Driven Development in the AI Era - A developer-focused look at spec-driven development: how spec files, CLAUDE.md and agent instructions written in Markdown are becoming first-class engineering artifacts.
• [Code & Coffee - Substack] Markdown Is Becoming the Language We Use to Build Software - A newsletter take on why plain text won: Markdown as the shared interface between humans and AI coding agents, and what that shift means day to day.
• [Code & Coffee - Substack] Contract-First Error Handling: Standardized Responses and Dead-Letter Queues - Extending contract-first integration to the failure path: standardized error responses, RFC 7807 problem details and dead-letter queues for Kafka-based systems.
• [Dev Community] What Being at JCON Europe Teaches Me (Beyond the Talks) - Lessons from attending JCON Europe as a speaker and attendee: community, hallway-track conversations and what conferences teach beyond the sessions themselves.
• [Code & Coffee - Substack] Happy 35 Years Python! Here's What Kept It Alive So Much Time! - A birthday retrospective on Python's design choices — readability, batteries included, a welcoming community — and why they still pay off 35 years later.
• [Dev Community] Python Just Turned 35, Here's What Kept It Alive All These Years - A timeline of Python's 35-year journey, from Guido van Rossum's 1991 release to today's dominance in AI, web development and data science.
• [Code & Coffee - Substack] Pydantic and Pre-commit Hooks on Main Quadrant of TechRadar from ThoughtWorks - Analysis of Pydantic and pre-commit hooks making it to the main quadrant of ThoughtWorks Technology Radar, and what it means for devs.
• [Medium] Complete Guide to Contract-First Integration with Spring Boot - End-to-end walkthrough of a contract-first stack: OpenAPI code generation, Kafka with Avro and Schema Registry, and Flyway migrations in a Spring Boot project.
• [Dev Community] Contract-First Integration: A Practical Guide for Developers - The concepts behind contract-first (API-first) development: why defining contracts up front lets teams build producer and consumer systems in parallel.
• [Medium] Architecture Decision Records Made Easy - A practical introduction to Architecture Decision Records (ADRs) and how to use them to document important technical choices effectively.
• [DZone] Building Realistic Test Data in Java - An enterprise-oriented comparison of DataFaker and EasyRandom: what each library does best and how to combine them in a test data strategy.
• [Dev Community] Generating Realistic Fake Data in Java with Quarkus, DataFaker & EasyRandom - Hands-on tutorial wiring DataFaker and EasyRandom into a Quarkus REST API that serves generated test data on demand.
• [Medium] Stop Faking "John Doe": How to Generate Realistic Data in Java with DataFaker + EasyRandom - The case against placeholder data: how unrealistic test fixtures hide bugs, and Spring Boot examples that produce production-like data instead.
• [Dev Community] Cassandra vs PostgreSQL: A Developer's Guide to Choose the Right Database - A comprehensive comparison between Apache Cassandra and PostgreSQL, helping developers choose the right database for their use case.
• [Code & Coffee - Substack] GraphQL vs. REST – Understanding the Differences and When to Use Each - Breaking down the key differences between GraphQL and REST APIs, with guidance on when to use each approach.
• [Code & Coffee - Substack] FastAPI in Action: Cutting Edge Async API Development - A quick tour of what makes FastAPI stand out among Python web frameworks: async-first design, type-hint-driven validation and near-zero boilerplate.
• [DZone] Top NoSQL Databases and When to Use Each - A practical guide comparing NoSQL technologies like MongoDB, Cassandra, Redis, and more, highlighting their strengths, limitations, and best use cases.
• [Code & Coffee - Substack] Java turns 30: An Innovation Journey Through Time and Technology - A timeline of Java from its 1995 launch by Sun Microsystems to today, and what 30 years teach us about building tech that lasts.
• [Dev Community] FastAPI Unleashed: Building Modern and High-Performance APIs - FastAPI in practice: natively async Python APIs with Pydantic validation and auto-generated Swagger/ReDoc docs.
• [Dev Community] NoSQL Fighters Arena: The Battle of Data Titans - Explore NoSQL databases reimagined as superheroes, each with unique powers and weaknesses, in a fun and visual battle-style format.
• [LinkedIn Pulse] Java is turning 30 soon! Here's Why You Should Care, Even if You're Not a Tech Person - Java is a super famous programming language, and it is almost turning 30. But wait, what exactly is Java, and why should it matter to you?
• [DZone] Automating Python Multi-Version Testing With Tox and Nox - A tool-by-tool walkthrough of Tox and Nox configuration for running the same Pytest suite across multiple Python versions, with Poetry managing dependencies.
• [Dev Community] Test Python Code Like a Pro with Poetry, Tox, Nox and CI/CD - Building a complete quality pipeline: local multi-version test runs wired into GitHub Actions so every push is verified against each supported Python release.
• [Dev Community] Python Multithreading: Unlocking Concurrency for Better Performance - The essentials of Python multithreading with practical examples and best practices to enhance application performance through concurrency.
• [DZone] Secure Password Hashing in Java: Best Practices and Code Examples - Secure password hashing using modern algorithms like BCrypt, Argon2, and PBKDF2 with salting and computational intensity for better security, as alternative to SHA-512.
• [Dev Community] Best API Performance Testing Tools in 2024 - Analysis of the top API performance testing tools for 2024, including JMeter, Postman, Locust, Gatling, and Grafana k6. For developers and QA engineers focused on API load testing.
• [LinkedIn Pulse] The Modern Landscape: A Comparison of Leading Java Frameworks - A Java framework landscape comparison between the top players on the market: Spring, Quarkus, Micronaut, JakartaEE and Helidon.
• [LinkedIn Pulse] Comparing the popular Web Application Servers in the market - A technical comparison between the main web and application servers available for Java applications, such as Tomcat, Jetty, Netty, Undertow, Nginx and Wildfly.
• [LinkedIn Pulse] Welcome to cyborgs era: a reading of technology with us 24/7 - Article about the integration of technology in our daily lives. It explores the various innovations that are blurring the line between humans and machines.
• [LinkedIn Pulse] GPT-4: The Next Leap in AI Language Models - What to expect? - A technical review on GPT-4, the latest AI language model by OpenAI, that brings significant advancements in natural language and accurate outputs.
• [LinkedIn Pulse] Google BARD vs. OpenAI ChatGPT: AI Technologies comparison - A technical comparison between the language models Google BARD and OpenAI ChatGPT, the cutting-edge AI technologies of the moment.
• [Freelance Business Month Europe] Freelance IT Market in Belgium - Talking about Belgium IT market movement and numbers. Where the opportunities are. How to start. Advantages and disadvantages. Business areas to target.
• More available on my LinkedIn, Dev.to, DZone, Substack and Medium.

• Location: Brussels region, Belgium
• LinkedIn: linkedin.com/in/wallaceespindola
• My Company's Website: www.wtechitsolutions.com
• Twitter/X: @wsespindola
• My Substack Blog: Code & Coffee by Wallace Espindola
• Medium Blog: medium.com/@wallaceespindola
• Dev Community: dev.to/wallaceespindola
• DZone Articles: dzone.com/users/1254611/wallacese
• LinkedIn Articles: linkedin.com/in/wallaceespindola/articles
• Presentation Slides: speakerdeck.com/wallacese
• Speaker Profile: sessionize.com/wallace-espindola
• Gravatar: gravatar.com/wallacese