Sebastian Kreft
Principal Engineer at Fintual
Chile
Summary
🤩
Rockstar🎓
Top SchoolSebastian Kreft is a Principal Engineer based in Chile with 17 years of experience building and leading high-impact engineering teams across startups and global tech firms. He has held senior technical and leadership roles—from Software Engineer at Google to CTO and Technical Lead positions—and now drives architecture and delivery at Topsort while advising Fintual. Deeply pragmatic, he blends hands-on Python backend expertise with system-level refactoring work, demonstrated by substantive contributions to Instagram’s LibCST parser where he improved syntax correctness, matcher performance, and language-edge cases like the walrus operator. Sebastian frequently operates at the intersection of product and platform, turning complex parsing and infrastructure problems into maintainable, testable solutions. Colleagues describe him as a steady technical coach who scales engineering practices without losing sight of code quality. He pairs an M.Sc. in Computer Science from Universidad de Chile with a history of shipping production systems across diverse domains.
17 years of coding experience
12 years of employment as a software developer
M.Sc. in Computer Science, M.Sc. in Computer Science at Universidad de Chile
German, Spanish, English
Stackoverflow
7,989reputation
268kreached
180answers
7questions
google-app-engine
top-1%
python
top-5%
Github Skills (21)
parser10
python10
google-app-engine10
parsing10
parse10
code-optimization9
datastructures-algorithms8
data-structures8
data-structure8
algorithms8
algorithm8
testing8
google-drive-api6
go6
nodejs6
Programming languages (23)
Github contributions (5)
Instagram/LibCST
Jul 2020 - Jan 2021
A concrete syntax tree parser and serializer library for Python that preserves many aspects of Python's abstract syntax tree
Role in this project:
Back-end Developer
Back-end DeveloperContributions:6 commits, 6 PRs, 13 comments in 5 months
Contributions summary:Sebastian primarily focused on improving the `libcst` library by fixing bugs and implementing enhancements related to its core functionality. Their contributions included validating `ImportAlias` and `Try` statements, allowing `ParenthesizedWhitespace` before function parameters, and addressing issues with the walrus operator. They also refactored the codebase, particularly the matchers module, and optimized the process of extracting wildcard matchers. Their work centered on maintaining the correctness and efficiency of the library's parsing and matching capabilities.
pythonconcreteparsersaspectssyntax-tree
sk-/html-linter
Sep 2014 - Feb 2017
HTML5 Linter based on Google Style Guide
Contributions:19 commits, 10 PRs, 16 pushes in 2 years 5 months
lintercssstyle-guidegoogle-stylehtml5
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