Sebastian Jeltsch
Entrepreneur at Self-employed
Zurich, Zurich, Switzerland
Summary
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RockstarSebastian Jeltsch is an entrepreneur and software engineer based in Zurich with seven years of experience building performant back-end systems and full-stack features. He spent eight years as a technical lead at Google, then moved into self-employment where he continues to apply deep systems and engineering instincts. Sebastian contributes to notable open-source projects—helping evolve libSQL (a community-driven SQLite fork) as a database engineer and optimizing rendering, hit detection, and draw-call batching for the popular flutter_map library. His strengths lie in pragmatic API design, low-level bug fixes in unsafe code paths, and measurable performance improvements across both database and client rendering stacks. Colleagues would describe him as a hands-on problem-solver who bridges database internals and front-end performance with equal fluency.
7 years of coding experience
8 years of employment as a software developer
Github Skills (14)
databases10
flutter-game10
rust10
sqlite10
dart10
embedded-database10
database-design10
flutter-apps10
database10
flutter10
api-design9
performance-optimization9
sql9
testing8
Programming languages (13)
Github contributions (5)
fleaflet/flutter_map
Sep 2022 - Jun 2024
A versatile mapping package for Flutter. Simple and easy to learn, yet completely customizable and configurable, it's the best choice for mapping in your Flutter app.
Role in this project:
Full-stack Developer
Full-stack DeveloperContributions:96 reviews, 29 PRs, 215 comments in 1 year 9 months
Contributions summary:Sebastian primarily focused on improving the performance and functionality of the `flutter_map` library. Their contributions include implementing draw call batching and optimizing the rendering of polylines and polygons. Furthermore, the user introduced hit detection capabilities to polylines, and resolved a number of positioning issues to improve the overall visual fidelity and user experience of the map. These changes included improving the efficiency of rendering within Flutter.
leafletwidgetdartmapflutter
tursodatabase/libsql
Jun 2024 - Dec 2024
libSQL is a fork of SQLite that is both Open Source, and Open Contributions.
Role in this project:Back-end Developer & Database Engineer
Back-end Developer & Database EngineerContributions:7 PRs, 14 comments, 6 issues in 5 months
Contributions summary:Sebastian primarily contributed to the back-end of the `libsql` project, focusing on database-related functionalities. Their work included implementing the `FromValue` trait for byte arrays, which involved modifying code related to rows, values, and parameters. The user also addressed a bug related to unpacking empty blobs in unsafe code and made API changes to make the Rows and Row interfaces more consistent. Furthermore, the user exposed column count functionality in individual rows, improving the API for interacting with database query results.
embedded-databaserustsqlsqlite3webassembly
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