Use the Velaro REST API with an API key to keep contacts in sync and send messages to them. Create the key under Settings > API Keys and grant the scopes you need.

Delete a contact

Send DELETE /api/v1/contacts/{id}. The contact is removed from your lists and can be restored for 30 days. Requires the write:contacts scope.

Create or update with upsert

Send POST /api/v1/contacts/upsert with at least one of uniqueId, email or phone. Velaro finds the matching contact (uniqueId first, then email, then phone) and updates only the fields you send, or creates a new contact. A 201 means created and a 200 means updated. If the keys point at different contacts the request returns 409 so nothing is merged by accident.

List custom field definitions

GET /api/v1/custom-fields returns the names, labels and types of your custom contact fields, so your integration knows which names customFields accepts. Requires read:contacts.

Send an SMS

Send POST /api/v1/sms with { "contactId": 123, "body": "text" }. Requires the write:messages scope and SMS on your account. Recipients who have opted out are not messaged and the request returns 422.

Send a WhatsApp template

Send POST /api/v1/whatsapp with contactId, templateName, optional language and variables, and an idempotencyKey. Sending the same key again never sends twice. Only approved templates can be sent, and opted-out recipients return 422.