Yingjun Lyu
Senior Applied Scientist at Amazon Web Services (AWS)
Los Angeles, California, United States
Summary
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Senior🎓
Top SchoolYingjun Lyu is a Senior Applied Scientist with 11 years of experience building static analysis and AI-driven security solutions for web and mobile applications, currently leading SAST and security risk remediation efforts at AWS. He specializes in automatic detection and repair of performance and security issues using static analysis, and has a track record of shifting security left to prevent data leaks, injections, and remote code execution at cloud scale. His PhD work at USC produced static-analysis tools that identified widespread database misuse in mobile apps and achieved 25–90% performance gains through automated optimization. Yingjun also has hands-on open-source experience contributing to Facebook’s widely used Pyre type checker, notably enhancing f-string parsing and type-checking in Python. He combines deep research rigor with production engineering—applying ML-for-security to harden code generated by generative models—bringing both academic depth and large-scale operational impact. Based in Los Angeles, he blends research, production systems, and practical tooling to drive measurable security and performance improvements.
11 years of coding experience
10 years of employment as a software developer
Doctor of Philosophy (Ph.D.), Computer Science, Doctor of Philosophy (Ph.D.), Computer Science at University of Southern CaliforniaSun Yat-sen UniversityHong Kong University of Science and Technology (HKUST)
Stackoverflow
1reputation
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Github Skills (13)
parser10
type-checking10
f-string10
type-check10
parsing10
python10
parse10
typechecker10
ocaml10
program-analysis9
software-quality9
static-analysis9
abstract-interpretation8
Programming languages (2)
Github contributions (5)
facebook/pyre-check
Jun 2018 - Jul 2018
Performant type-checking for python.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:13 commits in 1 month
Contributions summary:Yingjun primarily contributed to the development of the Pyre type checker, focusing on the implementation and enhancement of features related to type checking, especially for f-strings. They introduced and refined the parsing of f-strings, extracted expressions, and integrated type-checking mechanisms for these expressions within the Pyre framework. Their work involved modifying the AST (Abstract Syntax Tree) to support f-string parsing and implementing associated type-checking rules.
typecheckercontrol-flow-analysispythoncode-qualityabstract-interpretation
USC-SQL/Violist
Apr 2017 - Mar 2020
A String analysis framework for Java and Android apps
Contributions:38 commits, 34 pushes, 2 branches in 2 years 10 months
android-appsstringandroidkotlinanalysis-framework
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