Jelte Fennema-nio
Software Engineer at MotherDuck
Amsterdam, North Holland, Netherlands
Summary
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Rockstar🎓
Top SchoolJelte Fennema-nio is a seasoned software engineer with 13 years of experience building reliable, high-performance systems across databases, backend services, and front-end tooling. He has driven core features and reliability improvements at scale—most recently on the Citus distributed PostgreSQL engine at Microsoft and now at MotherDuck—while also leading low-latency feed and chat infrastructure at GetStream. His open-source contributions show a rare blend of security-minded systems work (BLE encryption cracking and fixes in pgbouncer) and practical engineering (PyLaTeX, gorocksdb, derive_more), including implementing hot TLS reloads and race-condition fixes in a widely used Postgres pooler. Comfortable across Go, Rust, Python and JS, he pairs deep database and concurrency expertise with a knack for modernizing test and deployment workflows. Based in Amsterdam, he combines rigorous academic training in systems and networking with a track record of shipping robust, production-grade software.
13 years of coding experience
12 years of employment as a software developer
VWO Bèta, VWO Bèta at De Werkplaats KindergemeenschapMaster’s Degree System and Network Engineering, Master’s Degree System and Network Engineering at University of AmsterdamVWO Bèta, VWO Bèta at Junior College Utrecht
English, Dutch
Stackoverflow
3,171reputation
611kreached
45answers
17questions
Github Skills (96)
dependency-management10
postgresql10
python10
high-availability10
testing10
rocksdb10
styled-components10
c1110
security10
c1710
vim10
code-generation10
linter10
embedded10
javascript10
Programming languages (31)
Github contributions (5)
JelteF/derive_more
Mar 2016 - Jan 2023
Some more derive(Trait) options
Role in this project:
Back-end Developer
Back-end DeveloperContributions:2 releases, 219 reviews, 586 commits in 6 years 11 months
Contributions summary:Jelte primarily contributed to the `derive_more` repository, focusing on expanding the functionality of the derive macros, particularly for conversion and operator traits. They implemented the `From` trait for newtypes and structs and added support for deriving traits like `Add`, `Sub`, `Mul`, and other mathematical operator traits, as well as supporting traits such as `IntoIterator` and providing examples to the docs. Furthermore, the user worked on enabling attributes such as `#[from(forward)]` for more versatile usage of the generated code. This required significant modifications to handle various data structures and generic code.
macrosderivetraitrustdeveloper-tools
JelteF/PyLaTeX
Jan 2014 - Oct 2020
A Python library for creating LaTeX files
Role in this project:Backend Developer
Backend DeveloperContributions:9 releases, 8 reviews, 629 commits in 6 years 10 months
Contributions summary:Jelte primarily worked on adding and modifying core features of the PyLaTeX library, which involves creating LaTeX files from Python. Their contributions include implementing new classes for documents, sections, tables, and math objects. They also refactored the code to use command classes and added support for features like subfigures, math matrix, and graph plotting. The commits demonstrate the development of foundational elements for the project.
python-librarypythonlatex
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