Run a campaign

Tip

Use a campaign rather than looping over POST /v1/messages. WhatsApp caps how many distinct people you may start a conversation with per day; a loop fails recipient by recipient once you hit that, while a campaign parks itself and resumes when the window frees up, without losing anyone.

1. Create it

   curl https://k-message.kerneltics.com/v1/campaigns \
     -H "Authorization: Bearer km_live_YOUR_KEY" \
     -H "Content-Type: application/json" \
     -H "Idempotency-Key: eid-2026-campaign" \
     -d '{ "name": "Eid offer", "template": "eid_promo" }'

   It is created in draft. Nothing sends.

2. Upload recipients

   Up to 1000 per call, in as many calls as you need.

   for (const batch of chunk(customers, 1000)) {
     await post(`/v1/campaigns/${campaign.id}/recipients`, {
       recipients: batch.map(c => ({
         to: c.phone,
         name: c.name,
         parameters: { name: c.firstName, code: 'EID20' },
       })),
     })
   }

   Each batch is written in one transaction. If one entry is rejected none of them are stored, so the campaign never holds a list you believe it does not have. The error names the offending index, because nobody can find the bad row in a thousand otherwise.

3. Start it

   curl https://k-message.kerneltics.com/v1/campaigns/{id}/start \
     -H "Authorization: Bearer km_live_YOUR_KEY" \
     -H "Content-Type: application/json" \
     -d '{ "send_mode": "spread" }'

   { "status": "processing", "queued": 480, "skipped": 0 }

   queued is what went out now, not the total. Under spread, the rest follow on later days as the allowance refreshes.

   Add "scheduled_at": "2026-08-25T09:00:00Z" to arm it for a future time instead of starting now.

4. Follow it

   Subscribe to campaign.completed and the final counts arrive when it is done. Or poll:

   curl https://k-message.kerneltics.com/v1/campaigns/{id} \
     -H "Authorization: Bearer km_live_YOUR_KEY"

Send modes

Mode	Recipients who do not fit today
spread (default)	Carried into following days until everyone is reached
today_only	Skipped, and counted in skipped

spread is right for anything that stays relevant, such as a product announcement. today_only is right for something that expires, such as a one-day offer, where sending it tomorrow is worse than not sending it.

Reading a stalled campaign

A campaign that stops moving is usually not broken:

{
  "status": "processing",
  "resumes_at": "2026-08-21T00:05:00Z",
  "throttle_reason": "Daily WhatsApp messaging limit reached"
}

That is spread doing its job. It resumes on its own.

GET /v1/accounts shows the number’s messaging_limit. It is Meta’s per-business-portfolio cap on distinct new conversations per rolling 24 hours, and it rises as your sending history and quality rating improve.

Pausing

curl -X POST https://k-message.kerneltics.com/v1/campaigns/{id}/pause \
  -H "Authorization: Bearer km_live_YOUR_KEY"

Recipients already handed to the workers still go out; the rest stay pending. Starting it again picks up where it left off.

Recipients can be added while a campaign is paused, but not while it is running: adding mid-send races the workers draining the queue, so whether the new rows went out would depend on timing.