Lily He
Software Engineer III at Squarespace
New York, New York, United States
Summary
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Rockstar🎓
Top SchoolLily He is a Software Engineer III with a decade of experience building resilient backend systems and observability pipelines, currently helping Squarespace serve millions of sites reliably. She has deep expertise in Scala and distributed systems from multiple roles at Twitter, contributing to flagship open-source projects like Finagle and Finatra and adding Prometheus-style metrics and adaptive concurrency controls. Her work spans production-grade libraries, testing enhancements, and security-focused improvements—she led service-to-service auth compliance enabling secure emission of 50B+ events per minute. Lily also brings geospatial API experience from Pelias and Mapzen and a research background in efficient genome assembly, a sign of strong algorithmic instincts beyond typical backend engineering. Known for shipping pragmatic solutions under on-call pressure and teaching Finagle to large cohorts, she blends hands-on coding with mentorship and systems thinking.
10 years of coding experience
3 years of employment as a software developer
Charles III University of Madrid (Universidad Carlos III de Madrid)Associate of Arts (A.A.), Liberal Arts and Sciences/Liberal Studies, Associate of Arts (A.A.), Liberal Arts and Sciences/Liberal Studies at Bard High School Early CollegeBachelor of Science - BS, Computer Science, Bachelor of Science - BS, Computer Science at Columbia University in the City of New York
English, Chinese, Spanish
Stackoverflow
13reputation
2kreached
0answers
1question
Github Skills (46)
application-framework10
javascript10
benchmark10
utilities10
lib10
concurrent10
testing10
app-framework10
sbt10
benchmarking10
finagle10
scala10
prometheus10
scalatest10
geocoding10
Programming languages (10)
Github contributions (5)
twitter/finagle
Jul 2019 - Jun 2022
A fault tolerant, protocol-agnostic RPC system
Role in this project:
Back-end Developer
Back-end DeveloperContributions:4 reviews, 38 commits, 2 PRs in 2 years 11 months
Contributions summary:Lily contributed to the `finagle/finagle` repository by adding a ConcurrencyLimitFilter, which depends on the Netflix concurrency-limits library. This filter dynamically adjusts concurrency limits based on request round trip times. The user also implemented end-to-end tests to ensure the ConcurrencyLimitFilter functioned correctly and collected the expected metrics, including dropped request counts when concurrency limits are exceeded. Furthermore, the user removed an incorrect explanation from the documentation related to response classifiers.
fault-tolerantrpcredismysqlfinagle
pelias/api
Jul 2017 - Sep 2017
HTTP API for Pelias Geocoder
Role in this project:Back-end Developer
Back-end DeveloperContributions:41 commits, 15 PRs, 23 pushes in 2 months
Contributions summary:Lily primarily contributed to the Pelias API, a geocoding service. Their work focused on implementing and refining core features, specifically adding a location bias functionality to the API. This involved modifying the schema for default parameters, setting location bias sanitizers, and adding the sanitizer to various API endpoints. They also worked on preventing override of location bias lat/lon parameters.
apipythongeocodinggeocoderpelias
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