> ## Documentation Index
> Fetch the complete documentation index at: https://headgate.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Go tasks

> Define typed JSON tasks and create durable envelopes.

```go theme={"system"}
type GenerateInvoice struct {
    InvoiceID string `json:"invoice_id"`
}

func (GenerateInvoice) Kind() string { return "invoice.generate" }

payload, err := json.Marshal(GenerateInvoice{InvoiceID: "inv-42"})
if err != nil { return err }
envelope := headgate.Envelope{
    ID: "invoice-job-42",
    Kind: GenerateInvoice{}.Kind(),
    SchemaVersion: 1,
    Fingerprint: headgate.Fingerprint(GenerateInvoice{}.Kind(), payload),
    Payload: payload,
    Queue: "billing",
    PartitionKey: "tenant-7",
}
```

<Note>
  `Kind()` is a durable public identifier. Keep it stable and register explicit version
  decoders when deployed payloads evolve.
</Note>