About

What Know It Cold is built on, and by whom.

Know It Cold is made by one independent developer. It began as a port of engram, an open-source command-line tutoring tool, to a phone app with a hosted backend, and it keeps engram's central idea: teach with a tutor that makes you commit before it tells you, grade what you produce without the grader seeing the conversation, and let a deterministic scheduler, never the tutor, decide when you see something again.

The parts

• Scheduling uses the FSRS spaced-repetition algorithm, ported line for line from engram and checked against it. Every date and interval you see comes from that engine, not from the AI.
• Tutoring, curriculum design and grading are done by Anthropic's Claude models, called through Cloudflare's AI Gateway.
• The service runs on Cloudflare Workers, with each learner's data in their own isolated store.
• The app is built with React Native and Expo.

Open source

Know It Cold itself is not open source. It includes open-source software under the MIT and similar licences; the notices are on the third-party notices page. The complete list, with each package's licence text, ships inside the app: Settings → About → Licenses.