Yann Simon
Software Engineer at commercetools GmbH
Berlin, Germany
Summary
🤩
Rockstar🎓
Top SchoolYann Simon is a seasoned software engineer with 17 years of experience, currently based in Berlin and building backend systems at commercetools. He specializes in Scala and reactive, non-blocking architectures, contributing to high-profile open-source projects such as fs2, Play Framework, http4s, and elastic4s to improve performance, interoperability, and testability. Yann’s work shows a pattern of thoughtful API design and low-level optimizations—e.g., refactoring internal data structures in fs2 for efficiency and adding buffer controls for reactive-streams interop. He also improves build and release automation (sangria) and hardens libraries against real-world issues like HTTP error handling and denial-of-service vectors. With engineering degrees from Technische Universität Berlin and earlier studies at McGill and UTC, he combines strong academic grounding with practical, production-grade library maintenance. Colleagues value him for quietly improving robustness and developer ergonomics across widely used Scala ecosystems.
17 years of coding experience
Computer Engineering, Computer Engineering at Technische Universität BerlinEngineer, Computer sciences, Engineer, Computer sciences at Université de Technologie de Compiègne (UTC)Computer sciences, Computer sciences at McGill University
English, German, French, French, English, German
Stackoverflow
458reputation
20kreached
14answers
7questions
Github Skills (54)
asynchronous10
library-design10
json10
github-ci10
back-end-development10
apidoc10
api-design10
async10
amazon-elasticsearch10
testing10
http10
sbt10
cicd10
java10
scala10
Programming languages (22)
Github contributions (5)
sangria-graphql/sangria
Oct 2019 - Jan 2023
Scala GraphQL implementation
Role in this project:
Back-end Developer & DevOps Engineer
Back-end Developer & DevOps EngineerContributions:11 releases, 215 reviews, 298 commits in 3 years 3 months
Contributions summary:Yann primarily contributed to the project by addressing build and release processes. They fixed sbt release issues and updated the sbt version, ensuring the project could be published and built correctly. They also updated dependencies related to testing and performance, including scalatest and scalafmt, and configured GitHub Actions for CI. The user also fixed a variety of warnings and performed code formatting.
apisangriaplay-frameworkgraphql-scalascala
json4s/json4s
Jun 2015 - Jun 2021
JSON library
Role in this project:Back-end Developer
Back-end DeveloperContributions:13 commits, 12 PRs, 7 comments in 6 years 1 month
Contributions summary:Yann primarily contributed to the JSON4s library, focusing on enhancing its functionality and improving its internal structure. They updated the library's dependencies, particularly related to Jackson, and added support for `JsonInput` in the `Serializer` interface. Additionally, the user refactored code to avoid instantiation of objects like JBool and lists, and fixed a denial-of-service vulnerability related to handling big integers. Their work demonstrates a focus on library maintenance, performance, and API design.
json-libraryscalajacksonjsonjson-parser
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