The SMS API is an SMS gateway for sending and receiving text messages from your website or application.

Create a client in any programming language to interact with the API. Check out our Quick Start Guides to get started with some of the most common platforms. If you have questions, browse our FAQ or contact us.


To send a text message, you will need at least one sending number assigned to your account. Our SMS API supports long codesshort codes, toll-free numbers, and international numbers. If you already have an account, you can manage your numbers here.

Our API automatically corrects for certain phone number errors.

Send and Receive Messages

Our SMS API supports both SMS messages and MMS messages. You can both send MT (Mobile Terminated) text messages and receive MO (Mobile Originated) text messages.

Here is how sending a message works:

  1. Your server or application makes a request to the API.
  2. The API sends a response back to you with the status of your request.
  3. The API sends your message to the appropriate aggregator.
  4. The aggregator delivers the message to the appropriate carrier.
  5. The carrier acknowledges receipt of the message (short codes only).
  6. The carrier delivers the message to the recipient’s cell phone.


The SMS API will automatically respond to select keywords when it receives incoming text messages.

When using a short code, you may also assign custom keywords.


Use postbacks to get notified whenever your outbound message has been sent, you have received an inbound message, or the status of your message has changed.

IP Ranges

To use the API, make sure to allow communication with the following IP address ranges:

  • –
  • –

Let’s start sending, together.