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Short Code Text Messaging Compliance

Short code text messaging is an excellent way to reach your customer and consumer base with relevant and time-sensitive information because text messages have a sense of urgency compared with other methods of communication. But it is important to note that text messaging is a permission-based medium that requires the sender to obtain the recipient’s consent to send SMS to their handset. Because consumers pay to receive text messages, the wireless carriers regulate the industry and create rules for interacting with recipients through SMS. CTIA is the International Association for the Wireless Telecommunications Industry that monitors text messaging for the carriers and issues violation notices. Non-compliant text messaging can result in citations, suspension, or termination of your short code campaign. The CTIA published a Compliance Handbook, effective June 2012, which clarifies the industry compliance rules, opt-in, and mobile campaign deployment.

Call to Action

A call to action is is an opportunity for a business to successfully capture a mobile number and an invitation for a consumer to provide their cell phone number in order to subscribe to content. Several examples include on-site signage, print advertisements, or a web page. The wireless industry requires that a call to action contains five pieces of information including:

Product description and quantity

What will the recipient receive by providing their cell number? And how often? (e.g. Receive account alerts 2-3/month)

Program identification

What is the name of the business, or the text messaging initiative? (e.g. Dr. O’s Medical Alerts)

Opt-out instructions

Include the keyword in bold that recipients must text to stop receiving messages. (e.g. Text STOP to unsubscribe)

Message and data rates may apply

Customers should know that carriers may charge them for these text messages. (e.g. Message & Data rates may apply)

Links to privacy policy and terms and conditions

Dedicated short code users must create a privacy policy. Shared short code users can use the policy drafted by CDYNE for each shared short code. Terms and conditions must be posted online. (e.g. Privacy Policy and Terms & Conditions)

Opt-In: Even if You Already Have a Business Relationship

It’s worth mentioning here that existing business relationships and the purchase of opt-in lists do not automatically allow a company to send text messages to those mobile numbers. For example, if you already communicate with customers via email, you must still get their permission to receive text messages. Or if you collect mobile numbers during an online transaction or other method – this does not count as an opt-in. Automatic enrollment in multiple programs is not allowed, and the CTIA requires a dedicated opt-in for each program. The CTIA  Compliance Handbook outlines four examples for capturing opt-in. In all opt-in scenarios, consent to receive text messages must be clear and accurate at the time the mobile number is given.

  • Enter a phone number online,
  • Click a button on a mobile Webpage,
  • Send an MO message containing an advertised keyword, or
  • Sign up at a point-of-sale location


The reason behind all the rules and regulations is to eliminate unsolicited text messages, or SPAM. The CTIA Compliance Handbook defines unsolicited messages as, “All messages delivered before a user opts in or after a user receives confirmation of opt-out, and any message delivered in excess of the quantity advertised, are considered spam.”

For more information about the laws that address SPAM, read the FCC’s guide titled “Spam: Unwanted Text Messages and Email.”

CDYNE supports only the sending of opt-in text messages from the SMS Notify! API for both short codes and DIDs.  In an effort to ensure that all text messaging sent through CDYNE SMS Notify! API is conducted responsibly, please read the Responsible Use Guidelines.

Contact CDYNE for more information about short codes.

Test SMS Notify! API for free.


SMS Notify! API System Keywords

SMS Notify! API is a programming interface that provides connectivity to wireless carriers. It allows developers to build business applications to send and receive text messages using DIDs or short codes. DIDs are SMS-enabled 10-digit phone numbers (e.g., 757-544-9510), and short codes are 5- to 6-digit numbers (e.g. 55512). Here is a PDF document outlining the differences between each method. One important feature of SMS Notify! is the system keywords. When a person begins a text message with a system keyword and sends it to your DID or short code, SMS Notify! will automatically send a text message reply. System keywords and responses vary between DIDs and short codes as outlined below.

DID System Keywords


System Response:“Business Name”-SMS Notifications.Txt STOP to end.Msg&Data Rates may apply.”Business point of contact.”

  • The default business name is the name used to sign up for the SMS Notify! account. This may be updated by contacting CDYNE.
  • The business point of contact is two forms of contact including any combination of phone number, email, or website.

System Response: This provider is now blocked. Text back RESUME to unblock your number.

  • SMS Notify! API will block the recipient’s number from receiving messages until the recipient sends RESUME.
  • CDYNE will log the recipient STOP request including the license key, sending DID, and recipient’s phone number.
  • The STOP response occurs at the license key level. SMS Notify! will only block messages from that same license key to the recipient’s phone number.
  • Other license keys may send to the recipient’s phone number.

System Response: OK.

  • This will allow SMS Notify! to send messages to a recipient who previously sent a STOP command.
  • License Key with Assigned DIDs: The recipient can reply RESUME to any DID assigned to the license key that logged the original STOP request.
  • License Key without Assigned DIDs: The recipient must reply RESUME to the original DID assigned to the license key that logged the original STOP request.

Short Code System Keywords


System Response:“Business Name”: Reply STOP to cancel. Msg&Data Rates may apply. Msg Freq per acct setup. “Business #.”

  • The default business name and number is the name and number used to sign up for the SMS Notify! account. This may be updated by contacting CDYNE.
  • The HELP response for short codes are at the license key level so you can set up multiple custom HELP responses per short code.

System Response:“Business Name”: You have opted out and will no longer receive messages from this service. “Business #”

  • SMS Notify! API will block the recipient’s number from receiving messages until the recipient sends RESUME.
  • The STOP response occurs at the license key level. SMS Notify! will only block messages from that same license key to the recipient’s phone number.
  • The reply to French keywords is the standard English reply.

System Response: Welcome to “ProgramName”. Reply STOP to cancel. Reply HELP for help or call “ProgramContact”. Msg&Data rates may apply.  Msg freq per acct setup. Pwr’d by CDYNE.

  • Shared short code system messages will contain “Pwr’d by CDYNE.” Dedicated short code messages will not.

Contact CDYNE for more information about short codes.

Test SMS Notify! API for free.


Receiving SMS Messages with Short Code Keywords

A short code keyword is a unique one-word phrase that identifies a business, product or service. Keywords allow multiple  businesses to run unique campaigns on the same short code. Likewise, a business using a dedicated short code can differentiate communications with multiple keywords. For example, your dentist places a sign in the waiting room that says, “Text SMILE to 55512 to get appointment reminders.” In this example, “SMILE” is the keyword, and “55512” is the short code. By texting SMILE to short code 55512, the patient is opting in to receive appointment reminders. Using the same short code, the dental office may run a separate promotional offer. For example, “Text WHITE to 55512 for $25 off teeth whitening.” In this way, patients choose the interaction they wish to receive from their dentist. Communication with short codes and keywords give businesses great flexibility and responsiveness when engaging their customers, patients, or clients with text messaging. Here are guidelines and rules to consider when using keywords:

Select User Friendly Keywords

Keep it short – A short keyword is easy to remember.

Make it memorable – An easy to remember keyword will generate a better response.

Use a single word – SMS Notify! will match the entire message when checking for incoming keywords. If an incoming keyword is followed by any characters, a match will not be made.

SMS Notify! Incoming Keyword Rules

  • Only 1 instance of keyword per short code
  • Keyword cannot be a system keyword (e.g., STOP, HELP, ect.)
  • Keyword must be at least 3 characters long
  • Keyword cannot be a typical SMS response (e.g., sure, yes, thanks, monday)
  • Keywords are not case sensitive; ‘THIS’ is the same as ‘this’ and ‘ThIs’

Using PostBackURL to Capture Incoming Keywords

Developer’s can set up automated responses to incoming keywords using the SMS Notify! API PostBackURL system. When a keyword is assigned to your short code, CDYNE can also assign a URL or webpage you designate. Set your application to look for the variable SMSResponse=1, which is posted when a message is sent to your short code, or when a response to your outgoing message arrives. PostBackURL data is posted behind the scenes, and is not visible on your webpage. Program your application to capture the PostBackURL variables that are passed to your webpage from SMS Notify! API.

Contact CDYNE for more information about short codes.

Test SMS Notify! API for free.


Bulk SMS With Short Codes

CDYNE is proud to announce SMS Short Code Service availability. SMS Notify! customers have requested bulk text messaging and can now send up to 35 text messages per second. A short code is a 5- or 6-digit number such as 99431 that is assigned to a business to send text messages over supporting carrier networks. SMS Notify! now supports U.S. and Canadian short codes.

Short codes come in two varieties: random or vanity. A random short code is assigned, and a vanity short code is a number or word you can request for example 77493 for “PRIZE.” They are easy to remember numbers businesses can use to communicate with their customers and clients.

Launching a short code requires access to wireless carrier networks and carrier approval. This includes a carrier application which details the message flow between your business and text message recipients. Short code setup and carrier approval typically takes 8-10 weeks. While setting up short code access, businesses can use SMS-enabled phone numbers (DIDs) to test their applications with SMS Notify! API.

Short codes are an excellent mobile communication tool to reach customers with immediate and relevant information.

Contact CDYNE today for more Short Code Service information.

Or sign up for a free trial license key to test CDYNE Phone Notify! API.

Developers find CDYNE SMS Notify! API integration details on the CDYNE developer’s wiki.