> For the complete documentation index, see [llms.txt](https://vincechain.gitbook.io/vince-chain-documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://vincechain.gitbook.io/vince-chain-documentation/3.-vince-chain-protocols/concepts/the-chain-id.md).

# The Chain ID

Every chain has a unique identifier (also called Chain ID). Tendermint and Tendermint-based applications have defined Chain IDs in the [Genesis.json](https://docs.tendermint.com/master/spec/core/genesis.html#genesis-fields) fields. To comply with both EIP155 and Cosmos standards for chain upgrades, Vince Chain-based chains use a special format for their unique identifiers.