Jay Feldblum
Software Engineer at Facebook
San Jose, California, United States
Summary
🤩
Rockstar🎓
Top SchoolJay Feldblum is a seasoned software engineer with 12 years of experience building and modernizing high-performance C++ systems, currently based in San Jose and working at Facebook since 2015. He specializes in backend engineering for networking, transport, and infrastructure projects—contributing to prominent open-source repositories such as mvfst (QUIC), folly, and fbthrift—where he focuses on performance, reliability, and migration to modern C++ practices. His work spans core protocol implementations, distributed systems, and build/CI improvements, often chipping away at technical debt to boost maintainability and compilation performance. Prior to Facebook he combined technical leadership and product-facing responsibilities as Associate Director of Technology and Business, giving him a pragmatic perspective on shipping production-grade software. Colleagues would note his attention to subtle code-quality improvements (e.g., reducing compilation overhead via template and iteration refactors) that yield outsized maintenance and runtime wins.
12 years of coding experience
8 years of employment as a software developer
Johns Hopkins University
Stackoverflow
65,331reputation
8.3mreached
836answers
4questions
character-encoding
top-5%
oop
top-5%
castle-windsor
top-5%
ruby
top-1%
base64
top-5%
dependency-injection
top-5%
Github Skills (134)
dependency-management10
mobile-development10
linq-to-sql10
controller10
package-management10
testing10
http10
authentication10
proxy10
cmake10
data-management10
refactor10
ruby10
ubuntu10
c1710
Programming languages (14)
Github contributions (5)
facebook/fatal
Oct 2016 - Oct 2022
Fatal is a library for fast prototyping software in modern C++. It provides facilities to enhance the expressive power of C++. The library is heavily based on template meta-programming, while keeping the complexity under-the-hood.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:96 commits, 43 PRs, 3 pushes in 6 years
Contributions summary:Jay refactored and optimized the `fatal::foreach` helper in the fatal library, changing the iteration method from compile-time recursion to parameter pack expansion to improve compilation performance and reduce compiler error output. They also refactored and expanded traits for qualifiers. The user further contributed by adding features related to qualifier manipulation and implemented several improvements and tests for this library. The changes focused on enhancing the library's core functionality and improving code maintainability.
cpptemplate-metaprogramming
facebook/fbthrift
Jul 2014 - Jan 2023
Facebook's branch of Apache Thrift, including a new C++ server.
Role in this project:Back-end Developer
Back-end DeveloperContributions:7 reviews, 1041 commits, 12 PRs in 8 years 7 months
Contributions summary:Jay's commits primarily focus on the modification and improvement of Thrift code. The contributions include cutting extra parentheses in cpp2 struct generated `operator==`, implementing a string overload of `json_quote_ascii`, addressing inconsistencies in test code, and improving efficiency in the processing of code. The changes span a range of files within the project, indicating a broad understanding of the codebase.
cppthrift
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