Introduction: Channels are how your RapidPro.app workspace sends and receives messages (and, for some providers, phone calls). Without at least one connected channel, your flows can’t deliver messages to contacts. This article explains what channels are, the main channel types you can connect, and key limits to keep in mind.
Connect the right channel (and understand limits)
If you just need the essentials, follow this quick path:
- Understand what a channel does (send + receive)
- Choose the channel type that fits your audience (SMS/Voice vs apps)
- Plan for throughput and scale for broadcasts
- Use External API if your provider/country isn’t listed
- Disable a channel temporarily without deleting history
Channels are the foundation of delivery—flows can’t message contacts without at least one active channel.
Step-by-Step Process
A channel connects RapidPro.app to an external messaging or voice service. Once connected, RapidPro.app can:
- Send messages from that channel
- Receive incoming messages to that channel
Channels can be:
- Phone-number based (SMS/Voice)
- App/social based (Messenger, Telegram, Instagram, etc.)
Choose the channel type based on how your audience communicates.
Aggregators (SMS & Voice)
Aggregators route SMS (and sometimes Voice) across carriers. They usually provide virtual numbers or short codes and connect via API. Common examples include:
- Twilio
- Plivo
- Vonage
- Clickatell
- Africa’s Talking
Voice (IVR)
Some channels support voice calls for IVR flows. If you plan to run phone-call workflows, use a voice-capable provider and follow the Voice IVR setup guides.
External API
Use an External API channel when your provider is not listed in the “Add a channel” options:
- You configure an endpoint in your system
- RapidPro.app sends outbound messages to that endpoint
- Your system sends inbound messages back to RapidPro.app
Throughput is the speed of messages sent by a channel, measured in messages per second. It depends on the provider and number type.
- Toll-free numbers may support higher throughput than standard long-code numbers.
If you don’t see an option for your country/provider:
- Use External API as a fallback, or
- Contact support to discuss adding a local aggregator integration
If you want to stop sending messages temporarily but keep the integration and history:
- Open Workspace settings.
- Go to Channels.
- Select the channel.
- Use the Disable option (if available in your UI).
[CAPTURE: Workspace settings → Channels list showing a channel selected with a “Disable” control visible.]
Common Issues & Quick Fixes
I connected a channel, but messages don’t send
Problem: Outbound messages fail or never leave the workspace.
Fix:
- Confirm the channel is enabled (not disabled).
- Verify the contact has a compatible URN (e.g., phone number for SMS/Voice).
- Check provider-side configuration (credentials, number capability, or API status).
I’m not receiving inbound messages on the channel
Problem: Contacts message the number/app, but nothing appears in RapidPro.app.
Fix:
- Confirm inbound messaging is enabled in your provider account (where applicable).
- If using an External API channel, confirm your system posts inbound messages back to RapidPro.app correctly.
- Send a test message from a real device and verify the provider logs/webhooks.
I hit a channel connection limit
Problem: You can’t add another channel.
Fix:
- Review existing channels and disable/delete unused ones if appropriate.
- Consolidate where possible (e.g., use one provider setup instead of duplicates).
- If you need more capacity, contact support to discuss workspace limits.