Simon Zelazny
Software Engineering Consultant at Self-employed
Poland
Summary
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Rockstar🎓
Top SchoolSimon Zelazny is a software engineering consultant with 11 years of experience building resilient, test-driven distributed systems and streaming platforms. He has driven production migrations, hardened real-time chat infrastructure with Jepsen-style testing, and optimized core back-end components for projects like WallarooLabs' distributed stream processor and the MongooseIM XMPP server. Comfortable across Erlang, Elixir, Haskell, C, Pony and Python, he blends pragmatic engineering with lean design and continuous delivery to ensure correctness under pressure. A proven remote collaborator, Simon pairs deep technical craft with mentoring and organizational influence, and his background in Japanese studies and translation adds a rare cross-cultural communication edge to customer-facing engagements.
11 years of coding experience
11 years of employment as a software developer
Japanese Language and Culture Research Program, Japanese Studies, Japanese Language and Culture Research Program, Japanese Studies at Tokyo Gakugei UniversityMaster's degree, Japanese Studies, Master's degree, Japanese Studies at University of Warsaw
English, Japanese, Polish
Stackoverflow
386reputation
9kreached
13answers
0questions
Github Skills (19)
xmpp10
erlang10
data-pipelines10
messaging10
testing10
mongooseim10
chat10
pony10
data-pipeline10
test-automation10
tcp9
clojure6
rabbitmq6
rabbitmq-exchange6
functional-programming6
Programming languages (17)
Github contributions (5)
WallarooLabs/wally
Jul 2018 - May 2019
Distributed Stream Processing
Role in this project:
Back-end Developer
Back-end DeveloperContributions:69 commits, 21 PRs, 156 pushes in 10 months
Contributions summary:Simon primarily focused on improving the `wallaroo/wally` project's back-end components, specifically related to distributed stream processing. They addressed performance and correctness issues within the core data processing logic of the `DataChannel` and `TCPSource` components. Their work involved buffer management, resizing, and buffer read operations. Furthermore, they modified the sequence ID generation, removing the potential for generating sequence IDs when reading the latest ID.
stream-processingstreaming-datadata-streamdata-processingstreams
esl/MongooseIM
Jul 2015 - Mar 2016
MongooseIM is Erlang Solutions' robust, scalable and efficient XMPP server, aimed at large installations. Specifically designed for enterprise purposes, it is fault-tolerant and can utilise the resources of multiple clustered machines.
Role in this project:Backend Developer
Backend DeveloperContributions:33 commits, 21 PRs, 40 pushes in 8 months
Contributions summary:Simon primarily contributed to the test suite for the MongooseIM XMPP server. Their commits focused on clarifying test assertions, parallelizing test suites, and refactoring existing tests for improved maintainability and efficiency. They also introduced support for storing carbon copy information in session tables and made modifications to the session management system. These changes demonstrate a focus on enhancing the testing infrastructure and improving the server's session handling capabilities.
fault-tolerantscalablexmpp-servererlangxmpp
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