Nabil Abdel-hafeez
Principal Software Engineer at REWE digital
Dortmund, North Rhine-Westphalia, Germany
Summary
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Rockstar🎓
Top SchoolNabil Abdel-hafeez is a Principal Software Engineer based in Dortmund with nine years of hands-on experience building scalable backend systems, currently shaping e-commerce engineering at REWE digital. He is an active Scala OSS maintainer—co-driving zio-http and zio-schema—and has contributed notable fixes and performance work to the widely used ZIO ecosystem, including resource-leak fixes, OpenAPI rendering, and optimized BitChunk implementations. Comfortable operating at both product and library levels, he blends pragmatic production engineering for the REWE online shop with careful API and internal-structure improvements in open source. Known for attention to correctness and low-level efficiency (endianness-aware bit packing, chunk slicing), he brings a systems-oriented mindset to API design and code organization.
9 years of coding experience
10 years of employment as a software developer
Bachelor of Science - BS, Computer Science, Bachelor of Science - BS, Computer Science at TU Dortmund University
Github Skills (20)
api-design10
async10
bitwise10
http10
zio10
resource-management10
scala10
http-server10
functional-programming10
bit10
openapi10
concurrency10
concurrent9
asynchronous9
effects9
Programming languages (7)
Github contributions (5)
zio/zio-http
Sep 2022 - Jan 2023
A next-generation Scala framework for building scalable, correct, and efficient HTTP clients and servers
Role in this project:
Back-end Developer
Back-end DeveloperContributions:9 releases, 419 reviews, 8 commits in 4 months
Contributions summary:Nabil primarily focused on fixing resource leaks and improving the internal structure of the `zio-http` project. They addressed a resource leak in `Http.fromResource` by correctly managing `ZipFile` resources. Furthermore, the user refactored the code by moving pure data classes to `zio.http.model` for better organization and maintainability, as well as adding OpenAPI json rendering to enhance documentation capabilities, showing a grasp of both code quality and API design.
http-clientscalaziohttp-serverwebsocket
zio/zio
Jan 2022 - Sep 2022
ZIO — A type-safe, composable library for async and concurrent programming in Scala
Role in this project:Back-end Developer
Back-end DeveloperContributions:33 reviews, 7 commits, 28 PRs in 7 months
Contributions summary:Nabil primarily focused on enhancing the `zio/zio` library by implementing and optimizing the `BitChunk` functionality. Their work involved creating specialized versions of `BitChunk` to handle `Int`, `Long`, and `Byte` data types, with a focus on endianness support. The user also optimized `slice` operations and introduced methods for packing and unpacking boolean chunks into byte, int, and long representations. Furthermore, they added methods to convert `Chunk`s of `Byte`, `Char`, and `String` to a string and added the `asBase64String` method.
asyncconcurrent-programmingscalatypesafezio
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