Hi, I’m Sirui Chen.
Full-stack engineer building backend systems, cloud infrastructure, distributed systems, and AI/NLP applications.
University of Pennsylvania CIS M.S.E. candidate (May 2026) with a B.S. in Computer Science and a second major in Mathematical Science from Washington University in St. Louis (CS GPA 3.98/4.00). I build React web apps, backend APIs, PostgreSQL data systems, distributed search infrastructure, OS components, and ML/NLP research pipelines. I care about readable code, product workflows, scalable systems, and cross-functional execution.
Projects
Featured work
Selected projects that show full-stack range across product, distributed systems, OS internals, and applied ML.
Authenticated dashboards, maps, charts, filters, and CSV export over a PostgreSQL schema that joins LA crime data with California retail sales records. Graded 99/100.
End-to-end distributed search platform with a custom crawler, indexer, PageRank, replicated key-value store, multithreaded web server, and an RDD-style compute layer named Flame.
C implementation of Unix-like OS features: a shell with job control and I/O redirection, a SIGALRM-driven priority scheduler over spthread, full process lifecycle with signals and zombies, and the PennFAT on-disk filesystem — all wired up to a sandboxed live terminal on this site.
Approach
How I build
A short read on what I optimize for as an engineer.
- I prefer typed contracts end-to-end — data is converted into well-defined, validated structures at the edge and stays typed all the way through the system, instead of carrying raw blobs around.
- I treat warnings as defects and edge cases as part of the spec. Defensive defaults, deterministic resource cleanup, and explicit error paths beat clever code that breaks under hostile input.
- I try to ship small, reviewable units behind real CI gates. Lint, typecheck, and build must pass before anything reaches production, and deploys are boring on purpose.
- I like working across the stack and across roles — UI craft, backend systems, infra, and talking to non-engineers about what we are actually trying to do.
Skills
What I work with
Grouped by where they show up in my day-to-day.
Languages
Frontend & Product
Backend & Data
Cloud & Systems
Engineering Quality
Experience
Recent roles
Research Assistant — Prof. Chris Callison-Burch·University of Pennsylvania
May 2025 – Aug 2025
Built and evaluated retrieval-augmented generation workflows for DARPA SciFy and OpenScholar using score-based filtering, contrastive model work, and domain data preparation.
Python Developer Intern·CambioML
Dec 2023 – Mar 2024
Built an LLM-powered data portal with Danswer AI to search datasets from AWS, Datarade, and Snowflake across ingestion, indexing, and user-facing discovery workflows.
Lab Assistant — Vision-Assisted Self-Driving F1Tenth Car·Washington University in St. Louis
Aug 2023 – May 2024
Improved model robustness in glare and shadow conditions through targeted data augmentation, experiment tracking, and evaluation.
Research
Selected research
University of Pennsylvania · May 2025 – Aug 2025
Retrieval-Augmented Generation for DARPA SciFy and OpenScholar
Designed and evaluated retrieval-augmented generation workflows for scientific question answering on DARPA SciFy and OpenScholar, with a focus on retriever ranking quality and reproducible evaluation.
Washington University in St. Louis · Aug 2023 – May 2024
Vision-Assisted Self-Driving F1Tenth Car
Improved perception robustness for a 1/10-scale autonomous racing car under glare and shadow, and integrated new sensor input through ROS.
Looking for a full-stack engineer?
I’m available for full-time roles starting after May 2026. The fastest way to reach me is siruichen2023@outlook.com.