Aaron contributed to both the schneems/rails and Shopify/rails repositories, focusing on backend performance and concurrency improvements. He enhanced ActiveRecord in schneems/rails by reducing memory allocations and enabling safer multi-threaded access through freezing and global caching of database type objects. Aaron also improved developer workflows by extending DevContainer scripts to support podman and run outside VSCode, streamlining containerized development. In Shopify/rails, he implemented global caching strategies to facilitate Ractor-based concurrency, reducing duplication and synchronization overhead. His work, primarily in Ruby and Shell, demonstrated a strong grasp of containerization, database management, and backend development, addressing both reliability and scalability.