SMS notifications help you reach a wide audience quickly, without an app or development work. You can send SMS (text) or MMS (image) messages to your audience of opted-in MSISDNs (phone numbers).

SMS uses the SMMP protocol to send to devices (MSISDNsThe mobile phone number of an individual in your Airship audience. Each MSISDN represents an individual mobile device. ) that have opted in for a specific Sender IDThe alphanumeric code that your SMS messages come from — like a phone number or name. Your audience subscribes to each individual sender ID they want to receive messages from. . SMS benefits include:

  • Immediacy: Send time-sensitive notifications.

  • Reach: Contact customers who don’t have your app, or re-engage customers who are inactive on other channels or at-risk.

  • Personalization: Send transactional messages triggered by a backend system, e.g., order confirmation and shipment tracking updates.

  • Mobile wallet integration: Deliver personalized passes, tickets, coupons, and more.

  • Integrated platform: Centralize all your engagement channels; manage personalization, scheduling, and deployment for all message types; and measure SMS alongside all your other channels, all in the Airship platform.

  • No app required: If you do have an app, however, SMS notifications are an additional channel that you can use to engage your audience. You can decide which channel (app, SMS, etc.) is more important for different types of messaging, adjust your messaging for different channels, set priority per channel, and much more. See Channel Coordination for details about priority channel and other cross-channel engagement strategies.

Use Cases

Sports Events

  • Before the event: Last-minute ticket offers, seat upgrades, parking coupons.
  • During the event: Coupons, promotions of venue facilities, promotion of sponsor experiences to increase partner activations.
  • Mobile wallet pass delivery: Coupons, tickets.


  • Campaigns: Location-aware promotions, promotions to drive in-store traffic, lifecycle marketing.
  • Transactional: Offer confirmations, order status updates.
  • Mobile wallet pass delivery: Loyalty card updates, coupons.


  • Day-of-travel: Flight reminders, promotions, loyalty benefits.
  • Mobile wallet pass delivery: Boarding passes, loyalty card updates, coupons.


  • Campaigns: Re-engage inactive or at-risk readers.
  • News: Preferred new categories.

SMS Users in Airship (Sender and MSISDN)

A mobile device is represented by an MSISDN. An MSISDN is the mobile phone number of a device in your Airship audience. While MSISDNs represent devices, in general, you can think of an MSISDN as a person — someone in your audience.

Your messages come from one or more Sender IDs. A sender ID is an alphanumeric code that your audience will see when they receive messages from you; it is essentially the phone number or name that your SMS messages come from. Members of your audience subscribe to each individual sender ID they want to receive messages from. Your sender ID could be a standard phone number, short code, or a set of alpha characters representing your sender, like your company name.

Each MSISDN — or member of your audience — subscribes to the sender IDs they want to receive messages from. If your project has multiple sender IDs, you should take care when sending your message to ensure that you reach the right audience members. Use the sender ID to select your audience, so you can be sure that you reach the right MSISDNs when you send your message.

SMS Notifications and Sending Methods

SMS notifications are text-based messages. They are viewed in the recipient device's native SMS client. If your message exceeds the character limitation, it will appear as successive messages to the user.

You can send SMS notifications either individually or combined with other channels. You can also send SMS notifications using AutomationA set of conditions that your audience must meet before they receive a message. and JourneysA series of messages that is initiated by a single automation trigger. Airship sends messages in the series based on your timing settings, and you can also set conditions that determine the continuation of the series. . Automation can be set up in the dashboard or the API. Journeys are available in the dashboard only.

MMS Notifications

You can send multi-media messages (MMS) to your SMS audience. MMS messages include a fallback, ensuring that users who can't view the original MMS message still receive a message that makes sense.

When sending an MMS message, you can provide the URL for your image or upload it to Airship. If you do not upload to Airship, you should use image assets you control and a dedicated media host to prevent delivery errors. Do not use images hosted on a site where others could change or remove the images you want to use in your messages.

MMS messages must be:

  • .gif, .jpeg, .jpg, or .png format.
  • Hosted over HTTP or HTTPS (for media not hosted by Airship).
  • Smaller than 2 MB for .jpeg and .jpg.
  • Smaller than 1 MB for .png and .gif.

We recommend that you use images 650 KB or smaller to improve deliverability. In general, you should use the smallest possible image size to ensure that your audience receives messages quickly, regardless of connection quality.

Airship can shorten links in your SMS messages. When you enable link shortening, Airship replaces your URL with a shorter or URL. You can also use a custom domain, e.g., See: Custom Short Link Domains.

Shortened URLs:

  • Reduce the total number of characters in your messages. Shortened links using airsp domains consume exactly 25 characters.
  • Produce click tracking metrics, helping you determine how effective your SMS messages are in driving traffic to your links.
  • Expire 60 days after they are sent.

Contact Airship if you want to use a custom domain for shortened links. To support a custom domain, you must configure your web server appropriately.

For Airship to recognize and shorten your links, your URLs must:

  • Begin with http:// or https://.
  • Begin and end with a space. Your URL cannot have beginning or trailing punctuation or space characters in the URL; spaces determine the beginning and end of the URL.

When you enable link shortening, Airship generates a unique URL for each member of your audience. Airship tracks engagement for each shortened link, producing reports to track total engagement and short_link_click events in the Real-Time Data Stream (RTDS), helping you track engagement down to individual audience members.

You may not want to use shortened links for static, easily recognizable URLs, e.g, links to your terms and conditions. If you want to use a persistent shortened link like, you must provide the URL yourself. You can enable or disable link shortening whenever you send a message from the Airship dashboard.


You can set a default link shortening setting in Settings » Configurations » Feature Settings. However, your project's link shortening setting does not affect operations in the API; you must set "shorten_links": true to shorten links in messages you send using the Airship API. See the SMS Object for more information.

Data & Analytics for SMS

Opt in/out counts are included in the Devices report and individual message reports. Message reports also include send counts and custom events for delivery events and errors.

These counts are also included in Performance Analytics, and you can open a Real-Time Data Streaming event stream to observe SMS-related events in real time.

SMS Configuration & Requirements

Contact Airship Support or Sales to provision your project for SMS notifications.

Your SMS channel requires a Sender ID. A sender ID is an alphanumeric code that your audience will see when they receive messages from you; it is essentially the phone number or name that your SMS messages come from. Members of your audience subscribe to each individual sender ID they want to receive messages from. Each individual user is represented by their msisdn (phone number) registered to a particular Sender ID.

Opt-In/Out Handling

Users must opt in to receive SMS messages from your Sender ID and can opt out at any time. There are two ways users can opt in or opt out of your SMS audience:

  • Mobile-Originated (MO) Message: A message originating from the mobile handset can contain a keyword that triggers an opt-in. The opt-in keyword can trigger a single or double opt-in flow.
  • External Opt In: Users can opt in to SMS messages through your app, website, or other channel. You must register these users through the API.

Mobile-Originated Keywords

A mobile-originated message is a message sent from a member of your audience (originating from the mobile handset of a user) to you. A Keyword is a word that you define to perform an action, like opt-in or audience attribution, when used in a mobile-originated message. You can apply tags to your audience based on the keywords they use, segmenting your audience to send relevant messages based on your audience's keyword-indicated interests.

Contact Airship Sales to provision keywords and associated tag operations. Airship stores your keywords and associated tag operations. Custom keywords and tag operations for keywords are not available through the dashboard or API.

By default, users can text you any of these words to opt out of notifications: STOP, STOPALL, UNSUBSCRIBE, CANCEL, END, QUIT, ARRET. You can also add additional opt-out keywords; like opt-in keywords, specialized keywords can provide additional data about opt-out behaviors.

Mobile-originated messages are represented as events. Each event records the keywords that your audience uses and additional identifying information. You can use these events to observe opt-in and opt-out trends in Performance Analytics, or to get events directly from Real-Time Data Streaming.

Mobile-Originated Single Opt-In

Single opt-in is the process of registering users and considering them opted in when they send you a single message containing a keyword. This method does not require users to confirm that they want to opt in through a second mobile-originated (MO) message.

While a single opt-in is a simple way to register users, it may not always be an optimal opt-in method. Airship mobile-originated opt-in handling defaults to a double opt-in process. Contact Airship if you want to take advantage of a single opt-in workflow.

The response to the keyword is a confirmation text message that provides information about the text program. The message usually:

  • Confirms that the user has subscribed to an on-going text program.
  • Provides the number of messages the subscriber can expect to receive.
  • Informs the subscriber where they can obtain more information and how they can opt-out.
BrandX: Welcome to the BrandX Info and Alerts Program! Message frequency varies by use. For help, reply HELP. To end, reply, STOP. Msg&DataRatesMayApply.

Mobile-Originated Double Opt-In

Double opt-in requires a user to send you a keyword indicating that they want to receive mobile messages, and a second keyword confirming their choice:

  1. Your audience texts a keyword to trigger the opt-in process.
  2. Airship sends your audience a message requesting confirmation using a keyword.
  3. Your audience texts the confirmation keyword, opting in to your audience.

Because each message in the opt-in workflow supports unique keywords, the double opt-in method provides multiple indices to categorize users as they opt in to your audience; you can add, remove, or replace tags for any of the opt-in messages, ensuring that you precisely segment your audiences and target future messages to the right users.

Non-Mobile Single Opt-In

If users provide consent to receive text messages without a mobile-originated keyword — like through your website or app — you can register them through the API in a single step. Use the /api/channels/sms endpoint with the date-time when the user opted_in.


It may take up to an hour before you can message new users. If you want to message a new SMS user immediately, you can register new SMS users and send a message simultaneously using the create-and-send API or the Upload Users Audience option to send your SMS message.

POST /api/channels/sms HTTP/1.1
Authorization: Basic <application authorization string>
Accept: application/vnd.urbanairship+json; version=3;
Content-type: application/json

    "msisdn" : "15035556789",
    "sender": "12345",
    "opted_in": "2018-02-13T11:58:59"

When registering your audience without a mobile keyword, it is your responsibility to obtain express written consent from users. If users have not provided sufficient consent, you should perform a double opt-in.

Non-Mobile Double Opt-In

If users provide their phone numbers and express interest in SMS messages through your website or app but do not give sufficient consent to receive SMS messages from a particular sender, you can register them through the Airship API without an opted_in value.

When you register a user through the API without an opted_in value, Airship sends them a message prompting them to opt in. The user must then respond with a valid keyword to opt in to notifications.


Airship generates a channel_id even when you register users who have not opted in. You can add tags to these channels and associate them with named users before audience members opt in.

sequenceDiagram Participant Audience Participant You Participant Airship Audience->> You: Registers via webform/app You->> Airship: Register user through API Airship->>Airship: Creates channel ID for audience You-->> Airship: (Optional) add tags to new channel Airship->> Audience: Sends opt-in request via SMS Audience->> Airship: Texts opt-in keyword to Airship note over Audience, Airship: Your audience/channel ID is opted in and can receive messages

When registering your audience without a mobile keyword, it is your responsibility to ensure that your users understand that they are agreeing to receive SMS messages from you and provide express written consent to receive SMS messages from you.

Handling Multiple Senders

Users opt in to messages from a sender. Your project can have multiple senders, and your audience can opt in to multiple senders within your project. To prevent a message from reaching the same user from multiple senders, you can select a specific sender ID in the Audience step when sending an SMS message.

If your project has multiple senders, selecting a sender ID:

  • Determines the sender that your message comes from.
  • Ensures that your message only goes to members of your audience subscribed to that sender.

Determining Timezone and Locale for SMS Channels

If you do not provide timezone, country, and/or language information when registering SMS users, Airship will infer timezone and country information from the msisdnThe mobile phone number of an individual in your Airship audience. Each MSISDN represents an individual mobile device. .

If you know your users' timezones, country codes, and language preferences, you can set these items when you create or update a channel.

You can use this information to make sure that you reach your SMS audience at the right time and in the right language.

POST /api/channels/sms HTTP/1.1
Authorization: Basic <application authorization string>
Accept: application/vnd.urbanairship+json; version=3;
Content-Type: application/json

  "msisdn" : "15035556789",
  "sender": "12345",
  "opted_in": "2020-02-13T11:58:59",
  "timezone": "America/Los_Angeles",
  "locale_country": "US",
  "locale_language": "en"

SMS Data Protection and Compliance

Requests to opt in or out of SMS notifications are handled by Airship. Our opt-in and opt-out database:

  • Is segregated from campaign content.
  • Is encrypted.
  • For opt-ins and opt-outs that occurred via mobile-originated messages on Airship SMS, Airship stores date/time data for those opt-ins and opt-outs for rolling 4 years.

Inbound (MO) Message Handling

In addition to standard opt-in and opt-out operations, you can configure a webhook to respond to mobile-originated messages.

Inbound message handling uses an SMS keyword webhook. Airship forwards mobile originated messagesA message sent from a member of your audience (originating from the mobile handset of a user) to you. from your audience to your webhook so you can process requests from your audience and send custom, targeted responses to individual members of your audience based on the keywords they use in mobile originated messages.

You can use a webhook to respond to mobile-originated messages when either the keyword or the information you want to respond with are variable and defined outside of Airship. For example, if users text the defined keyword balance to your sender ID, you can use a webhook to process incoming messages and respond with each individual user's balance. If a user texts a variable keyword, like order <#orderNumber>, you can use a webhook to respond with the status of the specified order number.

Talk to your Airship account manager to determine the static or variable keywords that you want to route to your webhook.

sequenceDiagram Audience->>Airship: Sends MO with Keyword rect rgba(0, 179, 6, .2) Airship->>Webhook: Forwards MO to Webhook Webhook-->>Airship: Respond HTTP 200, process asynchronously note over Airship, Webhook: Airship retries on 429/503 up to 4x end Webhook->>Airship: Issue custom response < 10 min Airship->>Audience: Sends custom response

Airship sends a payload to your webhook server at an /inbound-sms endpoint containing a mobile_originated_id that represents an individual MO message. You will use this ID and send a response using the /sms/custom-response API. Because you are responding to a message sent to you by a member of your audience, custom responses do not require users to opt in. However, the mobile_originated_id has a 10-minute lifespan; you have 10 minutes from the time a mobile-originated message is received to issue a response, after which the mobile_originated_id expires and you will be unable to respond to the inbound message.

Your webhook server must:

  • Have a public URL. Airship server IPs regularly change and must be able to reach your webhook.
  • Support an /inbound-sms (POST) endpoint to receive SMS inbound message payloads from Airship. Your webhook should immediately respond with HTTP 200 OK and process responses asynchronously. Long-lived connections can cause performance problems on both systems.
  • Support a /validate (GET) endpoint. You must respond to a validation request with the Validation Code issued when you set up your webhook in Airship.
  • Issue responses (to Airship's /sms/custom-response endpoint) within 10 minutes of the received_timestamp in the /inbound-sms payload.
  • Accept HTTPS connections.Airship uses TLSv1.2 with the following accepted cipher suites:


Additional Recommendations

Your webhook server should accept up to 100 concurrent connections. Airship will establish concurrent connections with your webhook when concurrent incoming messages require processing.

SMS Resources