# Topics

Part of the [ERC-1888 standard](https://github.com/ethereum/EIPs/issues/1888).\
\
**Topic** is a number which represents the topic of the certificate. Topic should define the [issuance data format](https://docs.zerolabs.green/zerolabs-tokenization-module/domain-definitions/smart-contracts/certificate-registry/issuance-metadata).

Topics 0-10 are reserved for ZeroLabs, with the other topics available to be claimed by any other [issuer](https://docs.zerolabs.green/zerolabs-tokenization-module/domain-definitions/issuer) that wants to use the ZeroLabs [Certificate Registry](https://app.gitbook.com/o/irNU67326uhFX5XZ6EKr/s/J1hmZlUO8raciusperMH/).

Examples for topic:

* 1 - ZeroLabs Token
* 2 - Renewable Energy Certificate by company X
* ...
* 10 - \<Available for anyone to claim> (open a [GitHub issue](https://github.com/zerolabsgreen/token/issues) and we will approve you as an issuer for that topic number)