Lennart Elsen
Staff Engineer at Open Systems
Zurich, Zurich, Switzerland
Summary
🤩
Rockstar🎓
Top SchoolLennart Elsen is a Staff Engineer based in Zurich with 11+ years building high-scale observability and security systems at the intersection of product, platform, and operations. He designed and operates global telemetry pipelines (30 TB/day) and multi-replica ClickHouse ingestion (20 TB/day), and maintains a distributed network telemetry system deployed across 10,000+ nodes. Equally comfortable in hands-on security engineering and cross-functional leadership, he led the creation of a security data product for VPN intrusion detection and drove an API-first strategy to standardize integrations and SDKs across teams. An active open-source contributor and former ZAP back-end developer, he has deep expertise in web application security and high-cardinality data architectures. Trained at ETH Zurich with a PhD-level background in security, he pairs rigorous system design with strong mentorship and a pragmatic focus on operational resilience.
11 years of coding experience
7 years of employment as a software developer
Master of Science (M.Sc.) Elektrotechnik & IT, Master of Science (M.Sc.) Elektrotechnik & IT at ETH Zürich
English, French, deustch
Github Skills (12)
javas10
zap10
spider10
html-parsing10
back-end-development10
java10
web-application-security10
security10
api-design9
testing9
security-scanner9
security-scan9
Programming languages (9)
Github contributions (5)
zaproxy/zaproxy
Mar 2022 - Apr 2022
The ZAP by Checkmarx Core project
Role in this project:
Back-end Developer & Security Engineer
Back-end Developer & Security EngineerContributions:23 reviews, 5 commits, 4 PRs in 26 days
Contributions summary:Lennart significantly contributed to the ZAP project by enhancing the spider functionality, a core component for web application vulnerability scanning. They focused on extending the spider to identify resources within HTML elements, including `applet`, `audio`, `isindex`, `object`, `table`, `td` and `video` tags. Further contributions included supporting form button attributes like `formaction` and `formmethod`, improving the form parsing capabilities. The user also worked on setting content types for POST requests.
owasp-zapzap-developmentsecuritydastowasp
Leyart/zaproxy
Mar 2022 - Jan 2025
The OWASP ZAP core project
Contributions:2 PRs, 59 pushes, 9 branches in 2 years 10 months
owasp-zapsecurityowaspzapcore-project
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