Zhichen Xu contributed to the facebookincubator/velox repository by building a robust RPC framework and integrating FAISS-enabled vector search. He established the core RPC infrastructure, including asynchronous function dispatch and plan nodes, enabling non-blocking cross-service calls and supporting both per-row and batch streaming modes. His work included end-to-end unit tests, cross-platform build improvements, and test infrastructure compatibility fixes using C++ and CMake. Additionally, Zhichen integrated FAISS as an optional dependency, enabling scalable vector search and cosine similarity, and implemented utilities for vector distance computations. These contributions enhanced Velox’s extensibility, performance, and readiness for ML and AI workloads.