Messages they open and read.

Bulk SMS and WhatsApp Business via API. Over 90% open rates. Reach any cell phone in LATAM, with or without mobile data.

Features

What you get

Bulk SMS API

Send thousands of SMS in seconds. Carrier integration in 8+ LATAM countries.

WhatsApp Business API

Reach people via WhatsApp without building your own bot. Click-to-respond templates.

Guaranteed Delivery

Automatic retry, fallback to SMS if WhatsApp fails, and delivery receipts for every message.

Metrics

Real-world performance

>90%

SMS Open Rate

98%

WhatsApp Delivery

<3s

Latency

Developer API

Send SMS or WhatsApp in one API call

POST /v1/sms/bulk

// Send bulk SMS
curl -X POST https://api.hellou.ai/v1/sms/bulk \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{recipients":["+573101234567","+573112345678"],"text":"Hello! Your code is 1234."}'

202 Accepted

// Response
{
  "batch_id": "batch_xyz123",
  "count": 2,
  "status": "queued"
}

POST /v1/whatsapp/message

// Send WhatsApp message
curl -X POST https://api.hellou.ai/v1/whatsapp/message \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{to":"+573101234567","template":"order_status","params":{order_id":"#12345"}}}'

202 Accepted

// Response
{
  "message_id": "msg_abc456",
  "to": "+57 310 123 4567",
  "status": "sent"
}

FAQ

Questions about messaging?

Why use WhatsApp instead of SMS?

WhatsApp reaches people with data; SMS reaches anyone with a cell phone. 90%+ of LATAM has WhatsApp, but not everyone has an active data plan. We let you use both: send WhatsApp first, fall back to SMS for those without the app.

What are the costs and per-message limits?

SMS costs $0.01–0.05 per message depending on country. WhatsApp costs $0.05–0.10. There are no per-message rate limits; we handle millions per day. Contact our team for bulk pricing.

How do I integrate bulk messaging?

POST to /v1/sms/bulk or /v1/whatsapp/message with a list of recipient numbers and your message. Our API handles retries, delivery confirmation, and fallback between channels.

Can I segment and personalize messages?

Yes. Tag messages with customer data (name, account, language), use template variables, and set send times. Our dashboard shows delivery rates, opens and responses per message.