# What is BTI?

The Blockspace Token Indexer: the instrument behind every block.space number.

URL: https://blockspace.wiki/answers/what-is-bti/

[BTI](https://blockspace.wiki/glossary/bti/), the Blockspace Token Indexer, is the instrument behind every block.space number. It walks every Bitcoin transaction from the genesis block and counts every byte exactly; nothing is sampled or estimated. It reads each token protocol's operations under that protocol's own rules, then writes [the three books](/concepts/the-three-books/), the judged attribution of blockspace to every token.

Sources:

- block.space docs: BTI · https://block.space/docs/bti
- Blockspace Holdings records

Updated: 2026-10-20