Marcin Stefaniuk
Kierownik Zespołu at Aplikacje Krytyczne
Warsaw Metropolitan Area Poland
Summary
👤
Senior🎓
Top SchoolMarcin Stefaniuk is a seasoned full-stack architect and team leader with 15 years of experience helping enterprises adopt DevSecOps and agile practices across finance, insurance, telematics, energy and retail. He operates fluently across enterprise, solution, product and system architecture layers, translating strategic goals into resilient microservice and messaging-based platforms. Marcin has led migrations, CI/CD and integration initiatives at organizations from TomTom and Credit Suisse to PKO Bank Polski and Hebe, and currently heads a team at Aplikacje Krytyczne. He brings hands-on engineering chops—early open-source contributions include implementing the NancyFX server generator in the widely used swagger-codegen project—paired with executive-level perspective reinforced by an Executive MBA. Known for introducing practical testing, automation and service contract practices in legacy environments, he balances technical depth with pragmatic delivery. Based in Warsaw, he combines a developer’s attention to detail with an architect’s emphasis on long-term operational robustness.
15 years of coding experience
22 years of employment as a software developer
Executive MBA, Executive MBA at University of WarsawM.A. Piano playing chamber music, M.A. Piano playing chamber music at Chopin University of MusicPostgraduate Project Management, Postgraduate Project Management at SGH Warsaw School of Economics
English, Polish
Stackoverflow
528reputation
15kreached
7answers
2questions
Github Skills (20)
open-api-v310
swagger10
api-specification10
code-generation10
dotnet-core10
csharp10
openapi10
openapi-documentation10
rest-api9
dotnet8
asp-net8
net8
context-free-grammar6
graphviz6
parsing6
Programming languages (6)
Github contributions (5)
swagger-api/swagger-codegen
May 2016 - Jun 2016
swagger-codegen contains a template-driven engine to generate documentation, API clients and server stubs in different languages by parsing your OpenAPI / Swagger definition.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:29 commits, 1 PR, 7 comments in 1 month
Contributions summary:Marcin primarily focused on developing the NancyFX server code generation component within the swagger-codegen project. They contributed the initial implementation of the NancyFX server generator, including key files and options. Further contributions involved introducing service interfaces, validation, and enum generation for parameters and properties. The user also worked on the petstore sample for NancyFX and addressed packaging and namespace-related issues.
openapi-codegenredocopenapi-specificationswagger-openapiopenapi
mstefaniuk/Concrete-Freetext
Apr 2011 - Feb 2012
Contributions:29 commits in 10 months
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