Bjørn Madsen
Lead Engineer at the LEGO Group
Vejle, Region of Southern Denmark, Denmark
Summary
🤩
Rockstar🎓
Top SchoolBjørn Madsen is a Lead Engineer with 14 years of experience, currently driving engineering at the LEGO Group from Billund and Vejle, Denmark. A dedicated functional programmer, he specializes in Scala, Elixir and Haskell and has made notable open-source contributions to flagship Scala projects like sttp, http4s and fs2—helping integrate Cats Effect, fs2, Circe and modern Scala 3 tooling. He combines deep library-level maintenance and refactoring skills with pragmatic backend engineering, particularly around streaming, async HTTP clients and dependency modernization. Known for improving maintainability and correctness (for example fixing resource closing in OkHttp backends), he brings both steady leadership and hands-on code craftsmanship. With a Cand.scient. in Computer Science, he pairs academic grounding with long-term practical delivery across enterprise systems.
14 years of coding experience
12 years of employment as a software developer
Cand.scient. Computer Science, Cand.scient. Computer Science at Syddansk Universitet - University of Southern DenmarkHTX Teknikfag: Proces, HTX Teknikfag: Proces at Odense Tekniske Gymnasium
Stackoverflow
378reputation
15kreached
7answers
7questions
Github Skills (24)
asynchronous10
dependency-management10
cats-effect10
async10
http10
sbt10
httpc10
scala10
stream10
http-client10
fs10
stream-processing10
functional-programming10
streaming10
circe9
Programming languages (25)
Github contributions (5)
http4s/http4s
Oct 2016 - Jun 2021
A minimal, idiomatic Scala interface for HTTP
Role in this project:
Back-end Developer
Back-end DeveloperContributions:20 reviews, 663 commits, 383 PRs in 4 years 8 months
Contributions summary:Bjørn contributed to the http4s project by modifying the jawn module, including updating the dependency to use jawnfs2 instead of jawnstreamz, and modifying the jawn instances. Furthermore, the user updated the circe module by modifying its test files. The commits also show dependency updates for jawn-fs2 and the core project.
idiomatichttp-clientscalafs2typelevel
softwaremill/sttp
Aug 2017 - May 2021
The Scala HTTP client you always wanted!
Role in this project:Back-end Developer
Back-end DeveloperContributions:27 commits, 11 PRs, 25 comments in 3 years 10 months
Contributions summary:Bjørn primarily focused on enhancing the Scala HTTP client (`sttp`) by integrating support for various asynchronous HTTP client backends, including Cats Effect and fs2. Their work involved modifying existing handlers and creating new ones to accommodate these frameworks, alongside the integration of Circe for JSON serialization and deserialization. Furthermore, the user addressed the proper closing of HTTP client bodies, particularly in the OkHttp backend, and refactored code for better maintainability and to leverage the existing core functionalities of sttp. The user also worked on refactoring and adding support for various Scala 3, which can be seen in the scala build files.
guzzlefinaglehttpclientfs2zio
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