Short code application reference

You will learn

Learn about the short code application process, including what you need to apply, how long it takes, and more.

Short code requirements vary country to country. Here, we explain what the strictest requirements may be and note any differences a specific country may have. 

About short codes

Short codes are 4- to 6-digit numbers primarily used for high-throughput SMS marketing. Wireless carriers also trust messages from short codes more than any other number type, meaning short codes are subject to significantly less filtering. 

Due to this, wireless carriers have strict requirements for how you can leverage SMS short codes. Short code programs must comply with carrier compliance requirements, industry standards, and applicable laws. Further, not all businesses are eligible for a short code. 

Short codes (or vanity short codes) are available for the following countries: 

• United States
• Canada
• United Kingdom
• New Zealand

If you want to know more about short codes before going through the checklist, open the dropdowns below.  

Who should get a short code? 

Short codes are best for anyone who:

• Wants to be subject to less filtering from wireless carriers
• Wants a number that appears more professional and is easy to remember 
• Are frequent or high-volume senders (e.g., 30,000 or more subscribers)
• Plans to send in New Zealand
• Wants to send many MMS messages in the US

Learn more about the benefits of short codes. 

Important note about short code compliance

There are 3 levels of messaging compliance: 

• Compliance with the law (e.g., country, state, or local laws)
• Compliance with industry guidelines
• Carrier guidelines

Carrier policies are often unpublished and only known through interactions with the carriers during the application process. These policies are also subject to change. Klaviyo works to stay informed of current requirements; however, changes to your short code application or examples may be requested at any time to maintain compliance. 

Klaviyo works to avoid any rejections or the need for re-review by vetting applications before they are sent to carriers. If a wireless carrier rejects a program, you may be able to modify it to meet the carrier’s requirements. Once the changes have been made, the program can be resubmitted to the carrier. However, resubmissions aren’t prioritized ahead of first-time applications, so be aware that the second review may result in delays in launching the short code.

Process of applying for a short code

While the process can vary from country to country, generally it follows these steps: 

1. Navigate to Settings > SMS > Add country, then select the option to apply for a short code.
2. Fill out the short code request form with information from the checklist below.
   • Note that if you want multiple short codes (e.g., short codes for several countries for more than 1 country, you must fill out this form multiple times. 
3. A Klaviyo expert reviews your application within a few business days. 
   • If anything is missing or needs to be updated, the requestor will receive an email from the Klaviyo specialist. 
4. Once the application is all set, Klaviyo creates mockups of your sign-up forms in your account. 
5. Klaviyo submits the application for approval to carriers and emails you to let you know. 
6. Carriers review your application and either approve or deny it. 
   • If migrating (also called porting) a short code, you must provide the lease for your short code during the carrier review. To get your lease, contact your previous SMS provider. 

Once you fill out the form, Incomplete shows as the status for your short code. This status will change to Active when carriers approve the short code. 

Timeline for short codes

If you are approved and change your short code number, you are required to notify recipients that you are changing numbers. 

Canada’s brownout dates

In Canada, carriers do not approve short code applications during a certain time of the year, known as the “brownout” period. The exact dates of this vary, but the brownout typically goes from mid-November through mid-January. 

While the carriers do review the applications that come in during this time, the short codes won’t be available to use until the brownout period is over. 

If you are requesting a new short code to use during the brownout, you must apply and be approved before this period begins. 

Short code application checklist

Before applying for a short code, complete the items in the checklist below. 

1. Review prohibited content and spam mitigation policies.
2. Pick your top 3 vanity short codes (if applicable).
3. Share company and contact information.
4. Determine SMS program service type(s).
5. Ensure your abandoned cart and sweepstakes programs are compliant (US only).
6. Create 3 example SMS messages.
7. Describe how customers can opt in to SMS.
8. Have SMS sign-up form example(s) ready.
   • Note: Klaviyo will create these for you. 
9. Check your disclosure language. 
10. Estimate your monthly message volume.
11. Audit your terms of service (TOS) and privacy policy.
12. Submit a letter of authorization.
13. Recommended: include any subscribe keywords you want to use.
14. If migrating: provide your short code lease. 

Review prohibited content and spam mitigation policies

Providers and carriers often filter SMS content related to sex, hate, alcohol, firearms, or tobacco (SHAFT) or spam messages. 

Of these, the only one that may be allowed is alcohol-related content, and only:

• When using age-gating
• In certain countries (not Canada or New Zealand)
• When using double opt-in

For all other industries, review your content to make sure that it isn’t prohibited for SMS and MMS messages.

Pick your top 3 vanity short codes (if applicable) 

If you are looking for a short code outside the US or want to choose the numbers in your short code, you need a vanity short code.

To find out which short codes are available, check the registry for that country: 

• US short code registry
• CA short code registry
• UK short code registry
• NZ short code registry

Collect company and contact information 

Gather information regarding your business, point of contact, and contact details in case someone needs to reach out for assistance. 

You’ll need to provide: 

• Your name and email 
• Klaviyo account ID
• Klaviyo account name
• Company name
• Company's website URL
  • If you have a URL specific to your short code program, provide that; otherwise, enter your main company website URL.
• Company physical or mailing address
• Primary contact name
• Primary contact phone number
• Support phone number
• Support email address

Determine SMS program service type(s)

Figure out what kind of SMS program(s) you want to run. 

Below are the most common types of SMS programs: 

• Promotional
  Provides marketing; advertising; coupons; or deals highlighting the latest products, services, discounts, events, and upcoming offers. 
  • If you plan to send abandoned cart reminders via SMS, this must be called out separately from promotional.
• Transactional
  Sends alerts, notifications, etc. (if any promotional content is in the message, it loses its transactional classification).
• Sweepstakes (US only)
  Includes contests or giveaways during which products and other prizes are provided at no cost to the participants. 

There are 2 very important things to keep in mind when considering your program type(s). Once a short code is approved: 

• Your SMS program must reflect your choice.
  • For instance, if you decided on both promotional and transactional:
    • Send both types of messages. 
    • Mention each type when collecting SMS consent (e.g., on your forms).
• It’s difficult to add a type later, and doing so requires an official program amendment for review and carrier approval. This amendment may also take several weeks. 
  • For example, if you choose promotional, but later want to use an approved short code for transactional messages, you can’t simply start sending them because your program was not approved for this new messaging type. 

Ensure cart abandonment/sweepstake programs adhere to guidelines (US only)

In the US, carriers have guidelines for anyone sending either sweepstake or cart abandonment messages (e.g., added to cart, abandoned cart, and abandoned checkout). 

These guidelines are: 

• Use double opt-in when collecting consent. 
• Get explicit consent to send cart abandonment SMS, sweepstake SMS, or both.
• Add disclosures about your cart abandonment/sweepstakes program to your mobile TOS and privacy policy
  • Note: we share examples in the section on disclosure language.
• For a cart abandonment program, you must also:
  • Send only 1 SMS per recipient in a cart abandonment flow. 
  • Send the SMS within 48 hours of the triggering event.

Due to the complexity of these program service types, carriers require additional information to ensure quality and legal compliance. If you use SMS for this purpose, review this article on US guidelines for SMS cart abandonment flows. 

Create 3 example SMS messages

For short code applications, carriers ask that you provide realistic examples of 3 SMS messages. Create examples of the text you intend to include in the messages. You do not need to create visual mockups or screenshots.

Since these are meant to be realistic examples, you don’t need to include every compliance best practice. While a response to subscribe keyword should include things like STOP, HELP, your SMS program name, and “message/data rates may apply,” an example of a “Happy birthday” text does not.  

Below are a few examples of SMS messages that you might provide:

• Brand name: New launch! SMS subscribers only - get it while you can! [LINK] Reply HELP for help, STOP to opt out
• Brand name: Hey [first name]. We know you like [profile_property], we just add a new variation. Get it now! [LINK] Reply HELP for help, STOP to opt out
• Brand name: [First name] we saved your item in the cart. There's only 4 left - don't sleep on this, they are NOT restocking [LINK] Reply HELP for help, STOP to opt out

Describe how customers can opt in to SMS

Wireless carriers also want to know how you plan to collect SMS consent. For this, share the ways you plan to collect consent, such as:

• Having recipients text your number with a keyword
• Using a popup, click-to-text, or embed form
• Checking a box at checkout

Understand requirements for collecting consent

Most countries require that customers give “explicit, written consent” before receiving an automated text message. The customer must understand what they’re signing up for. Sending a text message without the customer’s prior consent is prohibited. 

You cannot make consent to your SMS program a condition of purchase of property, goods, or services. Further, consent for another marketing channel (e.g., email) does not count as consent for SMS. Learn more about collecting SMS consent. 

In your form or other opt-in method, you must provide: 

• Separate opt-ins for transactional and promotional messages (if you plan to send both types using the short code).
  • While building your sign-up forms, use multi-checkboxes to allow subscribers to opt in to one or both messaging types.
• Disclosure language that clearly explains your SMS program (see the next section for details).

Check your disclosure language

Review to your disclosure language to check that it: 

• Is tailored for the country where you have the short code. 
• Specifies the name of the keyword, button, etc. 
• Includes examples of each type of message.
  • For promotional, it could be: “promos or cart reminders.”
  • For transactional, it could be: “updates, alerts, and information.”
• Shares the following information (along with your company’s information):
  • Service description and name.
  • Message frequency (e.g., “Message frequency varies”).
  • Contact info for information and opting out of the short code program (e.g., “Text HELP for help. Text STOP  or click the unsubscribe link to opt out.”)
  • Links to your short code program TOS and your privacy policy (e.g., “Terms of Service: [Link to SMS terms of service]. Privacy Policy: [Link to privacy policy].”)
• Includes the following (if required):
  • Message and data rates may apply.
  • Consent is not a condition of purchase.
  • By consenting, you agree to receiving messages sent by autodialer.

Below are 2 examples of countries where your disclosure language may need to be altered so your short code application can be approved.

Estimate your monthly message volume 

Provide information regarding your expected sending volume for SMS messages, including how many SMS you will send daily and weekly.

As an example: 

• 10,000 subscribers x 6 messages per month = 60,000 messages

Additionally, include information around your expected peak sending times through the day and expected volume during these peaks. Sharing these details can help to avoid deliverability issues if a carrier perceives an elevated volume as a potential spam problem. 

Audit your TOS and privacy policy

You must mention SMS in both a TOS and privacy policy to ensure compliance. The mobile content can be included either:

• Within another TOS or privacy policy

• As a separate, mobile-only TOS or privacy policy

Klaviyo can host your mobile TOS for you. 

While hosting isn’t available for privacy policies, you can follow the best practices and see example language for a privacy policy. Further, if you were with another SMS provider, they may have hosted a privacy policy that you can look at. 

Submit a letter of authorization (LOA)

You must submit and sign an LOA. The signature can be handwritten or signed via an electronic signature software, preferably one that tracks the signature date and identity. Simply typing in a signature is not accepted.

Your LOA should include:

• Brand letterhead
• Company name
• Current short code (migrations only)
• SMS program name (e.g., [Your Company Name] Notifications)
• Signature with typed name and title

Recommended: include any subscribe keywords you want to use

While not required, it's a best practice to inform Klaviyo about any subscribe keyword you are using (except for JOIN) or plan to use. 

The reason for this best practice is that if wireless carriers ever audit your short code program, having your keywords on file can help protect you. 

If migrating: provide your short code lease

If you’re migrating your short code to Klaviyo, you must work with your previous SMS provider. 

You do not need to provide the ID of the lease. Instead, contact your previous provider and ask them to transfer the lease to Klaviyo. 

We recommend contacting your provider once you receive an email that Klaviyo has sent your short code application to the wireless carriers for review. 

Next steps

After submitting short code to Klaviyo 

Once you submit your short code application, check your email regularly. Over the next few business days, a Klaviyo representative will follow up with you, either to request additional information or to tell you that they've sent your application to carriers. 

Carriers can take up several weeks, depending on the country, to review your application. These short code review timelines do not start as soon as you submit the application to Klaviyo, but only when Klaviyo submits the application to wireless carriers.  

Klaviyo will email you when your short code application is either approved or rejected. 

If your short code is approved

If your short code is approved, remember to:

• Change any tap-to-text forms to use the short code (this does not happen automatically). 
• Update any forms, subscribe pages, or other content showing your previous number.

The short code will take precedence for any subscribe keywords, flows, scheduled campaigns, etc. You can also start using the short code immediately. 

Additional resources

• Learn more best practices for creating an SMS terms of service and privacy policy
• Find out the difference between explicit and implicit consent