Choose an SMS Sending Number

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Please note that only account Owners and Admins will have the ability to add/manage sending numbers.

When you start using Klaviyo to send SMS messages, you will automatically be assigned a sending number. This is the number from which your text messages will be sent, as well as the number that new subscribers will text to confirm their subscription.

That said, you may want to change this number. Klaviyo provides several different options for you to lease on a monthly basis, which are outlined in this guide.

Sending Number Options

As of February 19, 2021, Klaviyo will provide you with a free toll-free number (1-8XX-XXX-XXXX) for anyone first setting up SMS. 

Do not delete your first free toll-free number, as this will not generate another free toll-free number. 

To change your sending number, navigate to Account > Settings > SMS. Under Sending Numbers, click Additional Numbers. You can select either Request Additional Numbers or Port an Existing Number from the resulting dropdown menu.


If you select Request Additional Numbers, you will be provided with the following options:

  • Long number (1-XXX-XXX-XXXX)
    When you select this option, you will then be prompted to select the number of long numbers you would like (up to nine). You will receive a new long number immediately upon requesting it.
  • Toll-free number (1-8XX-XXX-XXXX)
    You can only have one toll-free number per account. If you don't already have one, selecting this option will provide you with a toll-free number immediately.
  • Short code (XXX-XX)
    When you select this option, you will initiate the process of leasing a short code. We do not currently support shared short codes, meaning your short code will be unique to your business. When you request a short code, you will see your request move to a pending state and will receive an email from a Klaviyo representative regarding next steps.
  • Vanity short code (XXX-XX)
    When you select this option, you will see your request move to a pending state and will receive an email from a Klaviyo representative regarding next steps. You will then work with this representative to specify which numbers you would like included in your short code, provided the number is available.

At this time, the only way to choose your own sending number would be to purchase a sending number from a third party, like Twilio, and port it into Klaviyo, or to lease a vanity short code from Klaviyo ($1,800/month).

When you have more than one number in your account, different SMS subscribers may receive texts from different numbers. However, once someone receives a text message from you, they will always receive messages from the same number as long as it’s associated with your Klaviyo account thanks to a feature called sticky sending. For instance, if you have both a long number and a toll-free number, someone who received their first text from the long number will continue to get messages from that number, while anyone who’s first text came from the toll-free number will get texts from the toll-free number.

Porting over an Existing Number

If you are migrating over from another SMS sending service and you have an existing number that you would like to use to send text messages, you can port that number into Klaviyo. Note that porting a number will result in the loss of any voice capabilities, and that toll-free numbers cannot be verified or have MMS enabled. 

Select Port an Existing Number from the Request Additional Numbers dropdown. 


Next, you will see a modal confirming that you would like to submit a port request. To confirm this request, select Submit Port Request, and you can expect to be contacted by a Klaviyo representative. We can port over short codes, toll-free, and long numbers. However, we cannot port over shared short codes. If you were previously sending from a shared short code, you will instead need to request a brand new number.

SMS Sending Speeds

Below, we've outlined the major differences between long numbers, short codes, and toll-free numbers.

Number Type Sending Speed Price per Month Time to Provision
Toll-free number  3–150 mgs/second

Free if you set up after Feb 19, 2021

Otherwise, $2/month 

Plus additional throughput costs


Throughput increase takes ~1 week

Long number  1 msg/second $1/month Immediate
Short code  100+ msg/second

$1,300/month (random)

$1,800/month (vanity*)

Plus additional throughput costs

10–15+ week application process

Throughput increase takes ~1 week

*Vanity is the only option that allows you to specify the number, pending availability.

How to Choose the Right Number for Your Business

There are pros and cons associated with each type of number outlined above. To help you choose what's right for you, we've outlined some recommendations for each number type.

Long Number

The main benefits of a long number are that you can use it to start sending immediately, you don't need to request MMS, and it is cheapest type of sending number (except the free toll-free number provided). 

Generally speaking, it's better to use a toll-free number than a long number, as long numbers are subjected to more filtering by wireless carriers. If you do choose to use only long numbers, have one long number per every 200 profiles who opt into SMS marketing from your business. If you have more than 200 SMS subscriber for a single long number, you may experience deliverability issues.

Toll-Free Number

A toll-free number is similar to a long number, but it is more obvious that it's coming from a business because it's a toll-free number. Likewise, the benefits are similar: you can start sending immediately and it is a relatively low financial investment. The main distinction is that you can send more messages at once.

You can only have one toll-free number per account. 

Unlike long numbers, toll-free numbers can be verified. This can help increase deliverability, with more texts making it to your subscribers’ phones.

If you do decide to use this type of number to increase your throughput, remember that this will not apply for any MMS messages unless you have have MMS for toll-free numbers — toll-free numbers currently can't send MMS messages by default. You can request MMS to be enabled for your toll-free number once you have it verified or when you submit your number for verification. 

Short Code

If you have already established an SMS strategy and know for certain that this is a channel you would like to invest in, short codes are your best option. Short codes allow you the flexibility to send quickly to a large group of subscribers, which is a benefit if you have an existing SMS subscriber base and/or are migrating over from a previous SMS provider. Further, short codes are subject to less filtering from wireless carriers than long numbers. 

Short codes are also the only option that allows you to specify which number you're provisioned, so if brand recognition is very important to your business, this is another benefit.

While the application process for a short code can take several weeks, if you are certain this is a channel that you are going to use heavily, it is likely worth the wait.

Since Klaviyo does not use shared short codes, you will not be affected when they are phased out. 

Manage Your SMS Numbers

You can add up to 400 numbers in batches of no more than 20 to your Klaviyo account by clicking Request Additional Numbers. If you need more than 400 numbers, reach out to our Support Team.

If you later decide that you no longer need a number, you can release it by clicking the settings dropdown beside the number and selecting Release Number.


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