> For the complete documentation index, see [llms.txt](https://zer0-1.gitbook.io/zns/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://zer0-1.gitbook.io/zns/smart-contracts.md).

# Smart Contracts

NatSpec documentation for all ZNS contracts

ZNS consists of nine (9) smart contracts, eight (8) of which are upgradeable UUPS proxies. The system is modular where each contract is responsible for logic related to its role in the system. This upgradeability helps evolve the ZNS system over time, based on protocol needs and user feedback.

You can read more about upgradeability here: [Contract Upgradeability](/zns/smart-contracts/contract-upgradeability.md).

For detailed information about ZNS smart contracts, check out the links below:

[Access Control](/zns/smart-contracts/access-control.md)

[Registry](/zns/smart-contracts/registry.md)

[Domain Token](/zns/smart-contracts/domain-token.md)

[Registrars](/zns/smart-contracts/registrars.md)

[Treasury](/zns/smart-contracts/treasury.md)

[Pricers](/zns/smart-contracts/pricers.md)

[Resolvers](/zns/smart-contracts/resolvers.md)