SMS Senders

Sender types

There are various types of SMS senders, each with their own advantages and disadvantages.

Primary differences between sender types:

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Short codes

Short codes have several advantages that make them the superior sender type, including:

• Designed to send high volumes of messages at high throughput
• Short in length, making them easy for consumers to recall
• Capable of two-way messaging, so you can effectively manage opt-in and compliance workflows with keyword responses

However, they are the most expensive sender type and can take months to provision.

There are two short code types: dedicated and shared. In 2021, US mobile carriers discontinued approval for new shared short codes. Airship does not support shared short codes for outbound messaging.

Primary differences between short code types:

Long codes

Long code advantages:

• Less expensive and shorter provisioning time than short codes
• Support both voice and text
• May be recognizable to consumers if otherwise associated with your business
• Capable of two-way messaging, so you can effectively manage opt-in and compliance workflows with keyword responses

They are generally used for lower volume, transactional messaging and at lower throughput than short codes or alpha codes.

Primary differences between long code types:

Alpha codes

Alpha codes have become a common sender type for SMS marketers throughout the world, largely because of their advantages:

• Can be a brand name or other recognizable term
• Shorter provisioning time than short codes
• Lower in cost than dedicated short codes since they don’t require leasing and may not require registration
• Capable of high volume messaging

However, they are a one-way sender, so cannot receive inbound SMS (mobile originating, or MO) messages. This can be a problem for brands required to maintain regulatory compliance with SMS keywords. The next section explains how to maintain keyword compliance when using alpha senders.

Message forwarding

Brands may be required use a two-way sender in order to receive inbound (MO) messages so they can maintain regulatory compliance with SMS keywords. Maintaining compliance is not possible when using only a one-way sender, for example an alpha sender.

The main compliance concerns are opting users out of commercial messaging and providing a way to contact the sender for more information. Example keywords for compliance: STOP, HELP, CONTACT.

You can maintain compliance by forwarding messages from a two-way sender to an alpha sender.

• Inbound message handling — Inbound messages (MO) are forwarded to whichever associated alpha sender sent the last outbound (MO) message to the corresponding MSISDN within the last 72 hours.

  If an alpha sender has not sent an outbound (MT) message to a MSISDN within the last 72 hours, the inbound (MO) message will not be forwarded, and the subscriber will receive a generic response telling them that their request cannot be processed.

• Multiple alpha senders — You can use a single forwarding sender for multiple alpha senders. Inbound message forward to the alpha sender that last sent an outbound (mobile terminated, or MT) message to the recipient MSISDNThe mobile phone number of an individual in your Airship audience. Each MSISDN represents an individual mobile device.. This behavior is significant when using the same forwarding sender for multiple projects or using a shared short code as a forwarding sender.

• Keyword responses and actions — The alpha sender handles all keyword processing of requests and actions, such as triggering a text response, opting in a user, or applying a tag for segmentation. Keyword responses are also sent from the alpha sender, as if it had received the inbound (MO) message without forwarding. See SMS Keywords.

Any sender capable of receiving inbound (MO) messages can be configured as a forwarding sender. Forwarding senders operate in the same country of origin as the alpha sender.

See also SMS Compliance.

Setting up message forwarding

Airship configures forwarding senders for your project, however the forwarding sender cannot be configured to handle any keywords. Remove keywords for that sender before making your request. See SMS Keywords.

Contact Support  or your account manager with your request and include these identifiers:

If you do not know what senders are already configured for your project, you can find them in the Airship dashboard:

1. Go to Messages, then SMS Keywords.
2. Select Create new keyword.
3. Select Settings, then the SMS Sender menu. You will see all the long codes and short codes for your project. Each sender in the list is formatted as a 2-character country code followed by the actual long or short code.
4. Note the long and short codes, then leave the page without saving a new keyword.

If you need forwarding senders for multiple projects, you may want to make a separate request per project for easier tracking.

Support or your account manager will tell you when configuration is complete and you can start including the forwarding sender ID in your SMS messages.

Setting up keywords

Outbound messages should include instructions explaining how your SMS subscribers can respond. For example, you might include Text STOP to <forwarding sender ID> to opt out. See SMS Keywords to set up keywords for your alpha sender.