Kat Marchán
Staff Software Engineer at Fastly
San Francisco Bay Area United States
Summary
🤩
Rockstar🎓
Top SchoolKat Marchán is a Staff Software Engineer with 17 years of experience building developer tools, package managers, and runtimes, currently working on StarlingMonkey, Fastly's WASM-based JavaScript runtime. She has led small teams at Microsoft on JavaScript/TypeScript tooling for Visual Studio and been a core maintainer of the npm CLI and NuGet client tooling, blending deep systems-level knowledge with strong UX and editor integrations. A prolific open-source contributor, Kat has shipped foundational work across high-profile projects like node, npm, and the miette diagnostic library, improving error reporting and dependency tooling. Her background spans languages and stacks—from Rust and Go tooling to Elixir/Phoenix and C#—which lets her bridge runtime internals and developer-facing experiences. She also co-founded a cooperative arts platform where she combined product, community, and engineering responsibilities, reflecting an operator’s instinct for real-world constraints. Colleagues describe her as a pragmatic engineer who refactors for clarity and ships tooling that reduces friction for other developers.
17 years of coding experience
15 years of employment as a software developer
BA Film Linguistics, BA Film Linguistics at Hampshire CollegeHigh School Diploma, High School Diploma at Robinson School Puerto Rico 
English, Spanish, French, Japanese
Github Skills (52)
asynchronous10
dependency-management10
application-framework10
nuget10
yargs10
datetime10
javascript10
parser10
npm10
game-engine10
package-management10
scripting10
api-design10
game-dev10
async10
Programming languages (33)
Github contributions (5)
kdl-org/kdl
Dec 2020 - Aug 2022
the kdl document language specifications
Role in this project:
Back-end Developer
Back-end DeveloperContributions:12 releases, 195 reviews, 108 commits in 1 year 8 months
Contributions summary:Kat primarily worked on implementing the KDL document language parser. Their contributions involved defining the structure of the parser, including functions for parsing nodes, identifiers, and comments. They also added support for various data types such as strings, booleans, and numbers. Furthermore, the user created the foundational structure for parsing and representing the KDL language.
specificationserializationkdlspecificationsdocument-language
zkat/miette
Aug 2021 - Nov 2022
Fancy extension for std::error::Error with pretty, detailed diagnostic printing.
Role in this project:Back-end Developer
Back-end DeveloperContributions:61 releases, 144 reviews, 389 commits in 1 year 3 months
Contributions summary:Kat primarily focused on implementing core functionality related to error handling and diagnostic reporting within the `miette` repository. They sketched out a basic protocol and implemented traits for `Diagnostic` reporting. Their contributions involved refactoring return values, adding a dummy reporter implementation, creating improved span handling, and refactoring code for clarity. The user's work resulted in a refined API, allowing for improved handling of diagnostic and error reporting functionality.
stdrusterror-reportingerror-handlingerror
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