SMS Channel

Learn about SMS channel functionality on Omnisend

Ira avatar
Written by Ira
Updated over a week ago

Today, every customer gets a massive number of messages from every single subscription he has started — however, only a few end up in the conversation and even less in a purchase.

In Omnisend, we are keen on boosting the reach and providing more flexibility by contacting your customers through different channels. You can check why using the SMS channel is important and how to create Your SMS Program in Four simple steps on our blog.

In this article, we'll explain how you can use SMS to send promotional newsletters and Automated messages.


Before you start

Collect opt-ins for the SMS channel

SMS is a very intimate channel, offering proximity that other channels can’t necessarily achieve. With SMS, you can send a direct message to your customers wherever they are, no matter what they’re doing.

It’s essential to get explicit permission to send your marketing updates (not a one-time shipping notification) through SMS. There are a few ways to collect your customers' consent to receive your marketing through the SMS channel.

Omnisend allows you to collect the SMS channel opt-in, which is sufficient for sending your messages to non-US numbers. But to comply with the TCPA regulation for US customers, we also allow the collection of additional TCPA consent records.

SMS channel opt-in

TCPA consent

Signup forms

Subscriber preference center

Checkout for Shopify/Bigcommerce users

Import from the file

Signup forms

Collecting your customers with Signup forms is one of the best solutions. You can disclose what type of notifications they subscribe to, provide an incentive by offering a discount, and even start the dialogue by adding an SMS message to the Welcome sequence.

To comply with the TCPA requirements, you should also add a TCPA legal text to the Signup form. Otherwise, the TCPA consent record won't be added to the contacts you'll collect. Find more information on the Signup forms set up in the dedicated article.

Subscriber Preference Page

It is always a good idea to provide your customers with the ability to update their subscription preferences. You may add the input field for the phone number along with some other options.

Like with the Signup forms, you can add TCPA legal text to the Subscriber Preference page and collect TCPA consents.

Import from the file

When importing contacts with phone numbers, you can choose whether you want to upload them as subscribed to the SMS channel.

Important! If you are collecting your customers' phone numbers with other applications, you won't be able to pass your contacts with subscribed to the SMS channel status.

Segment SMS subscribers

Once you start collecting the opt-in for the SMS channel, you may create a Segment of the customers subscribed to this channel. 

If you want to collect TCPA consent from your customers, you may also create a Segment of the customers having this record.

SMS credits subscription 

To start using the SMS channel for your marketing, you must ensure you have enough SMS credits in your account. The number of SMS messages you can send with a single SMS credit is based on the price for a single SMS in your recipients' countries.

  • On the Free plan, you get a $1 credit for SMS messages. Since the price for a single message in the US is $0.015, with a $1 credit, 66 texts can be sent to US numbers.

  • On the Pro plan, you get FREE SMS credits equivalent to the price of your subscription. If you pay $59 on the Pro plan, you get $59 on your monthly SMS messages budget.

  • On any of the Omnisend plans, SMS credits can be purchased as a subscription service.

Check the article for detailed information on the SMS pricing on each paid plan. 

SMS channel setup on Omnisend

In Omnisend, you can use SMS to send scheduled Campaigns to notify your customers about upcoming events or sales, as well as Automated texts on any of the following occasions:

  • Welcome message

  • Browse Abandonment

  • Product Abandonment

  • Abandoned Cart

  • Order Confirmation

  • Cross-Sell

  • Order Follow-up

  • Cancellation Confirmation

  • Customer Reactivation

  • Birthday message

  • Customer Feedback

  • Custom message

  • Shipping Confirmation

Let's consider a few examples of SMS channel use:

  • One-time off SMS Campaign

For your very best sales and promotions, you can add a bit of urgency to your text messages. With SMS, you can jump straight to the topic and make sure the message is delivered on time.

  • Only SMS channel-based workflow

For example, you can send an Upsell at Shipping confirmation. Like any other transactional message, Shipping Confirmation has a colossal opt-in rate. The customer is waiting to receive critical information related to the order he has placed, so there is no way he will miss this message.

  • Multi-channel workflow, where you can include email, SMS, and any other channel to the flow

For example, the Customer Re-activation sequence, where you send a short text informing your customers about upcoming emails. If your customer was inactive for such an extended period, sending the Email message alone may not be enough. Therefore, an SMS reminder followed by an email message with the discount code is the best way to go!

SMS message restrictions

  • The display of a custom Sender's name depends on the recipient's country. If the sender's name is not supported in your selected country, our phone number will be displayed. Check here if the countries you are sending support the sender's name. The US and CA don't support the sender's name. However, once you send out an SMS campaign to the US and CA, we will provide you with a different dedicated phone number for each country.

  • We don't track open rates for SMS. Add a clickable link to your store to track SMS engagement and track the click rate in our reports.

  • Your clients will not be able to reply to your SMS messages. That's why adding a link will also help you communicate with your clients. You can add a link to a specific product, category, or post. You should also add opt-out instructions to allow your customers to opt-out at any time. Note it is mandatory to add the opt-out instruction to all non-transaction SMS sent to US customers.

  • We always recommend keeping your SMS message short, less than 160 characters long. A standard SMS can contain up to 160 characters, depending on the symbols used. It's up to your recipient provider, but some carriers might not deliver an SMS message longer than 160 characters. 

Amount of Characters Allowed per SMS

Check the table below to see how special characters in your message (e.g., a message with emojis) can affect the number of SMS you are charged for:

Number of SMS

Maximum GSM characters

Maximum Unicode characters




























When you send a message whose text is longer than the maximum number of characters per 1 SMS, we will automatically split the message for you, add a special header (User Data Header), and send multiple SMS to carriers.

What is a User Data Header?

The User Data Header (UDH) takes up 6 bytes and instructs the receiving device how to reassemble the SMS segments so that your whole message will be shown as one SMS on the receiving handset. The maximum number of characters per concatenated (long) message is slightly reduced due to the inclusion of concatenation headers (UDH). In GSM-7 (plain text) encoding, it takes 7 characters; in UCS-2 (special characters, emojis), it takes three characters.

Can you explain the math around characters per message?

Sure can! Here are some important units to start with:

  • SMS messages are sent in 140 bytes

  • 1 byte = 8 bits

  • In GSM encoding, 1 character = 7 bits

  • In Unicode (UCS-2), 1 character = 16 bits

  • UDH = 6 bytes

Message type


Max Characters per


GSM - 7 Single SMS

( 140 bytes * 8 bits ) / 7 bits

160 characters

GSM - 7 Multiple SMS

( ( 140 bytes - 6 bytes ) * 8 bits ) / 7 bits

153 characters

UCS - 2 Single SMS

( 140 bytes * 8 bits ) / 16 bits

70 characters

UCS - 2 Multiple SMS

( ( 140 bytes - 6 bytes ) * 8 bits ) / 16 bits

67 characters

Best Practices

Clear best practices for SMS marketing will determine whether your campaign flies or fails. Follow these tips to ensure maximum results from your next campaign:

  • Get explicit consent to receive marketing emails through the SMS channel. You need to explain to your customers what updates you will send. If they provide the phone number expecting to receive the Shipping Confirmation text, you have no right to send your marketing. 

  • Provide your customers with explicit, always-available opt-out instructions. If your customer doesn't want to be contacted through the SMS channel, he should be able to unsubscribe from the SMS channel only.

  • Start the message by stating your "BRANDNAME:". The recipient should recognize your brand right away. While in some countries, you may show your own sender's name, others may restrict it and present the phone number only. Omnisend is also shortening your links for clicks and sales tracking.

  • Start the conversation by sending transactional text messaging. You don’t want to send an SMS campaign to your customers out of the blue, especially if you’ve never sent them a message before. Even if you have permission to do so, introduce your customer to SMS via an opt-in or a transactional message to start the conversation. Then, move towards promotion once you’ve opened that door.

  • Think about geography and timing. If you’re sending SMS campaigns cross-border, this is something to consider. Segment your customers based on the country codes and schedule them accordingly.

  • Combine SMS with email and other channels for maximum impact. The benefits of using SMS marketing are tangible, and this doesn't mean you should forego email marketing for its character-limited cousin. SMS can pack an extra punch for time-sensitive offers.


Are mobile carrier charges included in the SMS/MMS price? Yes, they are. You won't pay more than what's shown on the 'price estimation' step.

What will happen if the phone number I'll send the SMS to will be invalid? If the phone number you're trying to send the SMS campaign to doesn't exist - it'll bounce and be unsubscribed automatically. Learn more about SMS bounces here.

My recipient did not receive the SMS message. Check our SMS Troubleshooting article or contact our support team for assistance.

Why did I pay x2, x3, x4... price for my campaign? The character limit for a single SMS message is 160 characters, so your campaign has likely been too long. Keep in mind that even when you pay for 2,3,4... SMS: The message can be shown as one long text on your phone. The reason is that most modern phones and networks support concatenation. So, it's still 2 or more SMS sent but merged into one by your phone and/or mobile provider.

Why SMS message sender's name is not showing for the recipient? Display of the custom sender's name in the text message your client receives depends on the country restrictions in which your client's carrier is based. Check the article on SMS Sender's Name restrictions for the full list.

What number will be shown if the sender's name is not received? When the display of the sender's name is restricted due to country restrictions, one of our selected phone numbers is shown to the customer.

How do we sync phone numbers from different platforms? Only the phone number synced from Shopify can be mapped with subscribed to SMS channel status. For the rest of the platforms and integration (phone numbers sync is designed), the phone number will be added to the customers' profile and non-subscribed to the SMS channel status.

Why don't I see any click rates for the SMS message sent? Since we cannot track opens for the SMS Campaign, we suggest adding a link to the message. If you didn't add any links to the content of the message, the click rate wouldn't be shown.

How can I ask my subscribers to provide me with their phone numbers? You can target them by a Landing page with the input field for the phone number or provide one in the Subscriber Preference Center.

Can my customers respond to the text messages I send? Currently, responding to the SMS messages you are sending is impossible. Therefore, we recommend using the wording, not calling for action. However, your US customers may reply with STOP and HELP keywords

What's the easiest way to conduct tests for SMS messages in automation? We recommend triggering the automation with your phone number by executing the action specified in the trigger. This way, both trigger and message content can be examined.

Can I send an image(s) via SMS message? Or can I send MMS? You can send MMS messages to the United States and Canada; more info here.

Why are my contacts non-subscribed/unsubscribed to SMS? To start receiving SMS messages from your brand, the customer should provide his opt-in record and explicit consent to receive marketing through the SMS channel.

Have any additional questions? Talk to us at [email protected].

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