I was recently working on implementing CRDTs for a company that did retail shelf edge printing (the sale tags and strips you see when you go the the grocery store). The idea was to build a PDF rendering engine in Rust that we would compile to WASM allowing the clients (stores) to render PDFs on the fly with their in-store devices and printers. One of the challenges was keeping tens or hundreds of thousands of product data (that could update hourly) in sync across thousands of stores.

Ideally when clients (corporate overlords) would send product data an event streaming broker (like Kafka) would log the product. One consumer would insert the product data into the SQL database (current implementation), one would generate CRDTs based on diffs from the current product model, and a chained consumer would broadcast the CRDTs to all connected clients.

The initial sync would be brutal so we'd still support server side queries and rendering but eventually the customers could generate the PDFs themselves regardless of if our server was busy (or offline which happened often).

It was a fun project and I helped lay a ton of the ground work but due to company politics and a generally toxic workplace I jumped ship. My new job would never need CRDTs so I'm now just sitting back and watching the space evolve.