Valkey / Redis
For new solutions we now prefer Valkey over Redis.
Valkey is the Linux Foundation fork created after Redis moved away from an open source licence, and we think it is now the better of the two: development has been more active, the performance work has gone further, and its governance is genuinely open. It is API-compatible with Redis, so existing clients, libraries and tooling continue to work, and several cloud providers now offer it as their default.
Redis remains a solid choice and we are happy to use it where a client prefers or requires it, or where it is already running.
We prefer to use Redis as in-memory key-value data store for specific cases such as a custom cache or queue management solution. In such relatively simple cases a relational database would be overkill and not a good fit.
Redis is market leader in this area and fulfils all our needs.