Daniel Castillo
Senior Software Engineer at Jasper
Austin, Texas, United States
Summary
🤩
Rockstar🎓
Top SchoolDaniel Castillo is a Staff Software Engineer based in Austin with a decade of experience building reliable, production-grade backend systems across startups and healthcare tech. He spans the full software lifecycle—from requirements and design to testing and deployment—and has led backend teams as Lead Engineer before moving into senior and staff roles at Jasper. A pragmatic problem solver, Daniel contributes to notable open-source Node.js projects like undici and Fastify, improving robustness, TypeScript typings, and documentation for widely used HTTP and web framework libraries. He blends hands-on bug fixes and test-driven improvements with configuration and API design, demonstrating both deep implementation knowledge and attention to developer experience.
10 years of coding experience
14 years of employment as a software developer
Bachelor's degree Computer Science, Bachelor's degree Computer Science at Southern Connecticut State UniversityAssociate of Science (A.S.) Computer Science, Associate of Science (A.S.) Computer Science at CT State Norwalk
English
Stackoverflow
61reputation
2kreached
1answer
2questions
Github Skills (22)
javascript10
apidoc10
clientside10
testing10
http10
typescript10
api10
typescript-types10
web-framework10
webclient10
nodejs10
typescripts10
documentation10
performance-monitor9
performance-analysis9
Programming languages (6)
Github contributions (5)
fastify/fastify
Jun 2022 - Jun 2022
Fast and low overhead web framework, for Node.js
Role in this project:
Back-end Developer
Back-end DeveloperContributions:68 reviews, 1 commit, 23 PRs in 1 day
Contributions summary:Daniel contributed to the Fastify web framework by addressing type-related issues and adding new configurations. Their work involved modifying TypeScript definition files to enhance type safety and correctness. The user added features like the useSemicolonDelimiter configuration, which changed the default behavior of the framework. They also updated documentation and made minor test suite corrections.
apihapispeednode-jsjavascript
nodejs/undici
Jul 2022 - Jul 2022
An HTTP/1.1 client, written from scratch for Node.js
Role in this project:Back-end Developer & QA Engineer
Back-end Developer & QA EngineerContributions:6 reviews, 1 commit, 9 PRs in 1 day
Contributions summary:Daniel primarily contributed to improving the stability and robustness of the `undici` library, focusing on fixing stream-related issues, including error handling and unexpected behavior. They addressed bugs related to `throwOnError` functionality and incorporated new tests to ensure the library's reliability. Additionally, the user added TypeScript definitions and updated the documentation, showcasing an understanding of both the internal workings and the user-facing API of the project.
node-jshttp-clientjavascriptnodejsscratch
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