Hosted templates

Lifecycle

A template has a stable ID and key, one editable draft, zero or more immutable published releases, and an active or archived lifecycle. Archiving prevents new key-based sends without deleting historical releases or usage.

Variables

Declare variables with keys, types, required state, and optional defaults. Rendering fails with 422 when supplied data does not satisfy the published contract. Inserted values are escaped by context.

Optimistic autosave

Each draft carries a revision. Send the current revision to PUT /templates/:id/draft. If another editor saved first, SendHQ returns 409; reload before overwriting.

Preview, test, publish

1. Render with representative sample data.
2. Resolve every error finding.
3. Send a test snapshot to an address you control.
4. Publish the exact draft as an immutable release.

Send by key

{
  "from": "hello@example.com",
  "to": [
    "customer@example.net"
  ],
  "template": {
    "key": "account-welcome",
    "data": {
      "first_name": "Asha"
    }
  }
}

A personalized template send requires exactly one To recipient and no Cc or Bcc. Use the batch endpoint for individualized recipients.

Provenance

Every template send records the template, release, compiler version, and rendered-content hash so an historical message can be traced to the content that produced it.