redb is an embedded key-value database written in pure Rust that embeds its store inside the application, so it runs without an external database server. The latest release of the GitHub repository cberner/redb is v4.4.0. That said, the release notes and changelog for v4.4.0 are not in the provided information, so this post covers only the repository description and the feature scope outlined in the README.
The README describes redb as a simple, highly portable ACID embedded key-value store. Data is kept in copy-on-write B+tree collections, and it provides a BTreeMap-based API along with ACID transactions that guarantee atomicity, consistency, isolation, and durability. It supports MVCC for concurrent reads and writes without blocking, crash safety by default, savepoints and rollback, and the file format is stable. The implementation was loosely inspired by lmdb; the license remains recorded in the repository history as Apache-2.0, while the README also offers use under the Apache License 2.0 or the MIT License. The star count is 4857.
However, performance comparison numbers and real adoption cases are not in the provided information, and the cost of the copy-on-write structure in actual workloads is unknown. The freshness, technology, and quality scores are blank, and only the momentum score remains, at a low 1.7 out of 10. The repository was started on September 23, 2018, but its current usage scale is not recorded. With evidence that thin, it is worth treating it only as a candidate to check when an embedded store is needed, rather than adopting it right away.