> For the complete documentation index, see [llms.txt](https://docs.zerolabs.green/zerolabs-tokenization-module/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.zerolabs.green/zerolabs-tokenization-module/domain-definitions/smart-contracts/certificate-registry/issuance-metadata.md).

# Issuance metadata

Depending on the topic, issuance metadata can differ.\
\
An example of issuance data, taken from topic #1:

```json
{
  generator: {
    id: "DEVICE_123",
    name: "Solar Farm A",
    energySource: "SOLAR",
    region: "EU",
    country: "HR",
    capacity: "1000000000",
    commissioningDate: 1652572800, // Unix timestamp
  },
  generationStartTime: 1652572800, // Unix timestamp,
  generationEndTime: 1652572800, // Unix timestamp,
  productType: "I-REC",
  data: "0x", // Additional unstructured metadata
}
```