Valkey: one cache for every MAD app

As the estate grew, the same questions hit the database again and again: the price list, the menus, the latest versions. We added Valkey, the open-source fork of Redis, as one cache for every app.

How we set it up

• One cache for the whole estate, not one per app: the singularity rule.
• Memory only, a fixed size, the oldest answers dropped first when it is full.
• No door to the outside: only our own apps on the same server can reach it, with a password.
• If it stops, every app carries on without it, straight from the database. A cache must never be a single point of failure.

Why open source

Valkey is community-run and free of licence surprises. Choosing it keeps our infrastructure ours, and the skills our team builds on it are skills that travel.

A cache should make things faster and never make anything break.

Watched from Central Command

Central Command shows whether Valkey is up, how full it is and how often it answers instead of the database, so we can see what it is worth, not just assume it.