Leon Piotrowski - Senior Software Engineer
Experience
Senior Software Engineer
Docplanner
- Lead development of internal/admin systems supporting operational teams, focusing on workflow clarity, usability, and reducing manual steps for non-technical users.
- Design and evolve Java + Spring Boot services and APIs with strong domain boundaries, predictable contracts, and maintainable architecture; drive pragmatic system design decisions for scalability and safe change.
- Deliver full-stack features across backend and UI, building internal interfaces with React and Angular to improve productivity, auditability, and consistency of internal processes.
- Build supporting integrations and workflow helpers using TypeScript/Node.js; use Python and Golang where they provide the best fit for automation, services, or performance-sensitive components.
- Raise engineering quality through code reviews, refactoring, and testing strategy improvements; maintain a high bar for readability, stability, and long-term maintainability.
- Support production reliability with structured troubleshooting, root-cause analysis, and iterative improvements to logging/monitoring practices and operational runbooks.
- Mentor engineers via pairing, reviews, and guidance on decomposition, clean code, testing discipline, and pragmatic UX decisions.
Software Engineer
Allegro
- Built and maintained high-scale services powering core business workflows in a distributed environment, balancing delivery speed with reliability and safety in production.
- Implemented microservice APIs primarily in Java, contributing to scalable design and stable integrations; delivered components in Golang where simplicity/performance were key.
- Developed internal tooling and operational workflows using TypeScript/Node.js plus React/Angular, focusing on fast iteration and clear interfaces for internal users.
- Worked deeply with SQL and relational data modeling, improving performance through indexing, query tuning, and careful schema evolution.
- Applied event-driven and asynchronous processing concepts (Kafka-style): robust error handling, retries, and idempotent processing patterns.
- Improved operational readiness through better logging/diagnostics, safer release practices, and strong ownership of production issues and follow-up improvements.
- Mentored junior engineers via reviews and pairing; drove higher PR quality, clearer designs, and stronger testing habits.
Software Engineer
Product Software House (B2B)
- Delivered end-to-end B2B features from requirements to production: analysis, design, implementation, testing, and release, with a strong focus on maintainability.
- Built backend services primarily with Java, plus supporting integrations in TypeScript/Node.js; used Python for automation/data processing tasks and Golang for selected services where appropriate.
- Developed responsive UIs and internal tools using Angular and React, translating business processes into clear workflows and consistent user experiences.
- Integrated with external systems and APIs, emphasizing predictable behavior, robust error handling, and stakeholder-friendly documentation.
- Practiced clean code and refactoring, writing tests that protected critical flows and reduced regression risk across releases.
Industry Experience
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Experienced in Information Technology, Healthcare, and Retail.
Business Area Experience
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Experienced in Information Technology and Product Development.
Summary
Backend-focused Senior Software Engineer with 9+ years of production experience delivering scalable, reliable, and highly available systems in high-traffic environments. I specialize in Java and Spring Boot, building clean, maintainable services and distributed systems with strong attention to performance, resilience, and operational reliability.
Experienced in microservices architectures, event-driven systems, and high-volume transaction platforms, with hands-on work designing APIs, asynchronous processing pipelines, and fault-tolerant services. I have also built integrations and services using Node.js/TypeScript, Python for automation and data tooling, and Golang for performance-critical components.
I focus on production-first engineering-observability, monitoring, and reliability-ensuring systems remain stable under heavy load. I’ve led migrations from legacy systems to microservices, implemented event-driven integrations using Kafka, and built REST/gRPC APIs for scalable platform services.
Beyond backend systems, I take a product-oriented approach when building internal tools and operational platforms, creating clear workflows and reliable interfaces that enable support, operations, and business teams to work efficiently. I’m comfortable leading delivery end-to-end, mentoring engineers, and driving improvements in code quality, testing practices, and operational excellence.
My experience spans distributed architectures, iGaming platforms, blockchain integrations, and high-throughput backend systems, where correctness, scalability, and performance are critical.
Skills
Technical Leadership: Architecture Decisions, Coding Standards, Reviews, Incremental Delivery, Mentoring
Workflow & Ux Mindset: Simplifying Complex Internal Processes Into Clear, Consistent, Fast Tools
Reliability & Troubleshooting: Production Support, Incident Analysis, Observability Mindset, Pragmatic Improvements
Full-stack Delivery: Backend Apis + Internal Ui (React/angular) + Integrations (Node/typescript, Python/go)
Backend: Java (8+ Years), Node.js, Spring Boot, Rest Apis, Microservices, Background Jobs, Integration Patterns
Frontend: React, Angular, Typescript, Next.js Fundamentals, Ui Workflow Design For Internal Tools
Languages: Java, Golang, Python, Typescript (Node.js)
Data: Sql, Relational Database Design, Indexing, Query Optimization, Migrations
Messaging / Async: Kafka Concepts (Events, Retries, Idempotency), Queue-based Processing Patterns
Devops / Delivery: Ci/cd, Docker, Kubernetes, Git, Release/rollback Practices
Quality: Tdd Mindset, Unit/integration Testing, Code Reviews, Clean Code, Refactoring, Design Patterns
Ops: Logging/metrics/alerting Mindset, Debugging Complex Production Issues, “You Build It You Run It” Attitude
Collaboration: Stakeholder Discovery, Translating Business Needs Into Technical Plans, Documentation And Alignment
Languages
Education
Deakin University
Bachelor’s Degree (Hons), Computing/Engineering (Computer-related) · Computing/Engineering (Computer-related) · Australia
Statistics
Experience
Global Experience
Expertise
Qualifications
Profile
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