RCM DRS 

Pulling documents out of DHPO one at a time is fine until someone asks for a month of transactions. DRS turns that into a batch: search, select, download, and get a zip — while a Socket.IO room streams incremental progress to whoever is watching, so a long-running job reports itself instead of appearing to hang. Rooms are addressable and resumable, so closing the tab does not kill the download.

The bottleneck was never the network, it was parsing. Every retrieved transaction is XML, and doing that on the event loop stalls every other request on the box. Parsing runs in a worker-thread pool sized to available cores, with workers recreated automatically on crash or non-zero exit so a single malformed document cannot drain the pool.

The rest is the unglamorous half that makes it deployable inside a hospital network: JWT with refresh-token rotation, optional TOTP two-factor, rate limiting, session logging, role-scoped user and client management, and a configurable outbound proxy for the many environments where nothing reaches the internet directly.