Citadel of the Mind

A software company in Sacramento, California. We build tools for attention.

We make one thing at a time and we finish it. Right now that is Whetstone, a training practice for sustained attention, in development for Android.

How we work

We measure what we build, and we say what the measurements will not support. Where the evidence for something is thin, we would rather write that down than write around it. So we wrote it down.

We do not run analytics, we do not use advertising or tracking libraries, and we do not ask for an email address to let you use something.

Contact

hello@citadelofthemind.com reaches a person.
privacy@citadelofthemind.com for anything about your data, including deleting it.

Last written 19 August 2026.