curl --request PUT \
  --url https://api.reply.io/v3/email-templates/{id} \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '
{
  "name": "Updated welcome email",
  "subject": "Welcome!",
  "body": "<p>Hi {{firstName}},</p><p>Updated content.</p>",
  "attachmentIds": [
    42
  ]
}
'

{
  "id": 101,
  "name": "Follow-up template",
  "subject": "Quick follow-up",
  "body": "<p>Hi {{firstName}},</p>",
  "folderId": 5,
  "folderType": "personal",
  "attachments": [],
  "createdAt": "2026-01-15T10:30:00Z",
  "updatedAt": "2026-02-20T14:00:00Z"
}