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Messaging Channels: SMS, RCS, and WhatsApp

The Qlara Platform API supports three messaging channels. Each channel serves different use cases and has its own capabilities, reach, and requirements.

SMS​

Short Message Service is the most widely supported channel. Every mobile phone can receive SMS, making it the best choice when you need universal reach.

  • Content: Plain text only (up to 160 characters per segment, concatenated for longer messages).
  • Templates: Not required. You can send any text content.
  • Delivery receipts: Available via polling or webhooks.
  • Best for: Transactional notifications, OTPs, alerts, reminders.

API endpoint: POST /message-server/sms/send (SMS Universal API)

RCS​

Rich Communication Services brings rich media capabilities to the native Android messaging app. RCS messages support images, carousels, buttons, and suggested actions.

  • Content: Text, images, cards, carousels, and interactive buttons.
  • Templates: Required. Create and manage templates via the API before sending.
  • Delivery receipts: Available via polling or webhooks.
  • Best for: Marketing promotions, product showcases, interactive customer engagement on Android.

API endpoints: Dedicated RCS Send and RCS Templates APIs.

WhatsApp​

WhatsApp Business API lets you reach users on the world's most popular messaging app. WhatsApp enforces strict template approval policies through Meta.

  • Content: Text, images, documents, videos, buttons, and list messages.
  • Templates: Required and must be approved by Meta before use. Templates are associated with a phone number.
  • Delivery receipts: Available via polling or webhooks.
  • Best for: Customer support, order updates, appointment reminders, marketing (with opt-in).

API endpoints: Dedicated WhatsApp API for sending messages and managing templates.

Comparison​

FeatureSMSRCSWhatsApp
Rich mediaNoYesYes
Template requiredNoYesYes (Meta-approved)
Delivery receiptsYesYesYes
Two-way messagingLimitedYesYes
ReachUniversalAndroidWhatsApp users
Approval processNoneInternalMeta review

Choosing a channel​

  • Need universal reach? Use SMS. It works on every phone.
  • Targeting Android users with rich content? Use RCS for native rich messaging.
  • Reaching WhatsApp users? Use WhatsApp for high engagement rates and rich media.
  • Not sure? Start with SMS for reliability, then add RCS or WhatsApp for richer experiences.

Tracking delivery across channels​

Regardless of the channel, you can track delivery using:

  • Polling: GET /messages/status/{customerMessageId}?channel=SMS (or RCS, WHATSAPP) returns the current delivery status. channel is required.
  • Webhooks: Configure an HTTPS callback to receive real-time status updates. One URL receives DELIVERY events for all three channels, plus READ and INBOUND events for RCS and WhatsApp. See the Webhooks guide.