> For the complete documentation index, see [llms.txt](https://telegraph-1.gitbook.io/what-is-telegraph/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://telegraph-1.gitbook.io/what-is-telegraph/getting-started/core-concepts.md).

# Core Concepts

- [Message Data](https://telegraph-1.gitbook.io/what-is-telegraph/getting-started/core-concepts/message-data.md): What's in a message?
- [Time Based Thresholds](https://telegraph-1.gitbook.io/what-is-telegraph/getting-started/core-concepts/time-based-thresholds.md)