Over the last decade, Redis has become one of the most popular NoSQL DBs delivering on the promise of high throughput and low latency. What started as a pure C code base is gradually being augmented with Rust due to the trifecta of safety, concurrency, and speed. A primary example is thre RedisJSON module which turns Redis into a document DB. The talk outlines the principal architecture of the re-implementation of RedisJSON, the challenges encountered and the solutions for these. The focus is on the practical aspects rather than conveying theoretical knowledge. A comparison with other open source document DB concludes this presentation, concentrating on latency and throughput aspects.