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WhatsApp lets users stop marketing messages from a business number without blocking it. When a contact does, Meta notifies Kapso, Kapso records the preference, and marketing template sends to that contact on that number are refused. The scope is narrow and per number:
  • Only MARKETING-category templates are blocked. Utility and authentication templates, and free-form messages inside an open session, always go through.
  • The preference is scoped to the number the contact stopped. Sends from your other numbers are unaffected.
  • A contact with no recorded preference is subscribed.
The preference can only be set by the contact, inside WhatsApp. There is no API or dashboard control to opt a contact out or back in — to resume, the contact taps Resume promotions (or messages you and re-enables marketing) in WhatsApp.

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Blocked sends

Sending a marketing template to a stopped contact returns 422:
Do not retry the same send — it will keep failing until the contact resumes. Switch to a utility or authentication template, or send from a different number. The check runs before billing, so refused sends are never charged. Other send surfaces handle it without erroring:
  • Broadcasts mark the recipient suppressed and skip them. See Marketing opt-outs in broadcasts.
  • Workflow send-template steps record the send as skipped and the workflow continues.

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Check a contact’s preference

The identifier is a contact UUID or phone number. The response has one entry per number the contact has a recorded preference on:
status is stopped or resumed. marketing_allowed is what you should branch on before a marketing send. An empty data array means the contact never changed their preference — subscribed everywhere. Fetch a single number with GET /whatsapp/contacts/{identifier}/marketing_preferences/{phone_number_id}. A 404 with "Marketing preference not found" means the contact has no recorded preference on that number — subscribed. Check the error string before treating a 404 as subscribed: a mistyped identifier returns "WhatsApp contact not found" and an unknown number returns "WhatsApp configuration not found".

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Mirror opt-outs into your system

Subscribe to whatsapp.contact.marketing_preference_changed. It fires on every real transition — stop and resume — with a monotonic sequence to order deliveries by.

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In the dashboard

The contacts list shows a Marketing column and a subscribed/unsubscribed filter. The contact panel lists the preference per number. Starting a conversation with a marketing template warns and disables send when the contact has stopped that number, and broadcast details show how many recipients will be skipped before you send.