To send SMS campaigns, your contacts must explicitly opt in to receive SMS marketing. Consent is required by International Law and Omnisend's Terms of Use.
Like email permissions, contacts choose which channels they want to receive – email, SMS, or both – and can unsubscribe from any channel at any time.
Before sending your first SMS campaign, ensure your contacts have opted in to SMS marketing.
Related guides:
Before You Begin
⚠️ Critical compliance requirements:
SMS uses single opt-in only. Omnisend supports double opt-in for email only. SMS uses single opt-in – once a customer opts in through any method below, they're immediately subscribed to your SMS list. SMS double opt-in is not available and is not required by GDPR or TCPA regulations.
Separate checkbox required for US/Canada. For TCPA compliance (US/CA), use a separate, dedicated checkbox for SMS opt-in. A combined checkbox (e.g., "I agree to receive email and SMS marketing") may be rejected during toll-free number verification. Each channel requires independent consent with explicit language. For GDPR compliance (Europe only), one checkbox with clear language stating consent for both channels is acceptable.
Checkboxes must be unchecked by default. SMS opt-in checkboxes cannot be pre-selected in Omnisend forms. Customers must actively check the box to provide valid consent. Pre-checked boxes violate compliance requirements and will cause toll-free number verification rejection. Exception: WooCommerce checkout allows pre-selection.
Ways to Collect SMS Opt-in
1. Via Omnisend Signup Forms
Omnisend offers multiple signup form types where you can collect SMS opt-ins. To set up SMS opt-in:
Go to Forms → Create Form or edit an existing form
Add a phone number field
Enable SMS opt-in
Add TCPA legal text block (required for US/Canada compliance)
Required Consent Text for SMS Compliance
For US/Canada SMS compliance (TCPA), your opt-in forms must include:
Your business name
Description of messages customers will receive (promotional, marketing)
"Consent is not a condition to purchase"
"Msg & data rates may apply"
Message frequency information ("Message frequency varies" or specific number)
Opt-out instructions ("Reply STOP to cancel")
Customer care information ("Text HELP for help")
Link to your Privacy Policy
Link to your Terms and Conditions
Example TCPA-compliant consent text:
"I agree to receive recurring automated marketing text messages from [Business Name] at the phone number provided. Consent is not a condition to purchase. Msg & data rates may apply. Msg frequency varies. Reply STOP to unsubscribe or HELP for help. [Privacy Policy link] [Terms link]."
Omnisend signup forms automatically include TCPA-compliant legal text when you enable the SMS opt-in and add the Legal Consent block. Learn more about signup forms
2. Subscriber Preference Center or Landing Page
Ask existing customers to update their subscription preferences and add their phone number for SMS marketing.
Go to Store Settings → Preference Center to add an SMS opt-in option. You can also add TCPA legal text here to collect TCPA consents for US/Canada customers.
3. Text to Join Promotions
With Text to Join, customers sign up for your SMS marketing list by texting a keyword to your phone number.
Setup:
Go to Store Settings → SMS → Generate phone number to get your toll-free number
Your default keywords are JOIN, SUBSCRIBE, or START
Promote your keyword and phone number to gather leads
Promoting Text-to-Join
Share your keyword and phone number through:
Email campaigns and order confirmations
Social media posts and bios (Facebook, Instagram, TikTok)
Instagram stories with discount codes
Website banners or popups
Printed receipts or product packaging
In-store signage
Example promotion: "Text JOIN to 1-833-XXX-XXXX for 10% off your next order!"
⚠️ TCPA compliance: When promoting Text to Join, include TCPA disclosure text in your promotions explaining:
What messages customers will receive (promotional, marketing)
Message frequency
"Msg & data rates may apply"
"Reply STOP to opt out"
4. Checkout Opt-in (Shopify & WooCommerce)
Shopify Checkout
Shopify merchants can collect SMS opt-ins at checkout.
Setup:
Go to Shopify Settings → Checkout → Customer contact
Scroll down to Marketing consent
Enable the SMS marketing checkbox option
Omnisend is compliant with the Shopify SMS checkbox, and phone numbers will sync to Omnisend Audience with the correct subscription status.
WooCommerce Checkout
The Omnisend plugin allows you to add an SMS opt-in checkbox at WooCommerce checkout.
Setup:
Go to WordPress → Omnisend Plugin settings
Check "Add an opt-in checkbox to the checkout page."
Customize the SMS consent text
During checkout, everyone who checks this box will sync to Omnisend as an SMS subscriber.
5. Import Existing SMS Subscribers
If you're migrating from another platform and already have customers who opted in to SMS, you can import them.
Setup:
Go to Audience → Imports → Import contacts from a file
Upload your CSV file with phone numbers in international format (+country code + number)
Check "Import phone numbers as subscribed to SMS channel"
⚠️ Important: Only import contacts with documented SMS marketing consent – not just contacts who provided a phone number at checkout. You must have records of their prior opt-in for compliance. Store consent records (date, source, method) as custom properties for compliance documentation.
💡 Note: TCPA consent records collected in other platforms do not migrate automatically. You must have documented proof of consent for imported contacts.
Compliance by Region
SMS opt-in requirements vary by region:
US and Canada (TCPA)
Requires express written consent with specific disclosures
Must include all required TCPA legal text (message frequency, data rates, STOP/HELP instructions, privacy policy)
Checkboxes must be unchecked by default
Separate checkbox recommended for SMS (distinct from email)
Toll-free number verification required
Europe (GDPR)
Requires explicit consent before sending SMS marketing
Must include privacy policy link
Clear unsubscribe method required
One checkbox can cover both email and SMS if language is clear
Serving multiple regions: If you serve customers in both US/CA and EU, ensure your forms meet the strictest requirements (TCPA + GDPR). Use separate checkboxes and include all required TCPA disclosures.
Track Your SMS Subscribers with Segments
After you start collecting SMS opt-ins, create segments to track your SMS subscribers.
SMS Subscribed Segment
This segment shows contacts subscribed to the SMS channel:
Go to Audience → Segments → Create segment
Add rule: Subscription status → is subscribed to → SMS channel
TCPA Consent Segment (US/Canada)
This segment shows customers with TCPA consent records:
⚠️ Important: Only send SMS campaigns to contacts with valid TCPA consent records if you're targeting US/Canada customers.
Platform-Specific Notes
Shopify: Phone numbers collected via Shopify checkout with the SMS opt-in checkbox enabled are automatically synced as SMS subscribers.
WooCommerce and BigCommerce: Phone numbers are synced to Omnisend but marked as non-subscribed by default – even if customers provided them at checkout. You must collect SMS opt-in separately using Omnisend forms, the WooCommerce plugin checkbox, or other opt-in methods.
Other platforms: Check your platform's integration documentation to understand how phone numbers and SMS opt-in status are synced.
FAQ
Does Omnisend support SMS double opt-in?
No. SMS in Omnisend uses single opt-in only. Once a customer opts in through a signup form, Text to Join, or checkout, they're immediately subscribed to SMS. Double opt-in for SMS is not required by GDPR or TCPA regulations. Double opt-in is only available for email subscriptions.
Can I use one checkbox to collect consent for both email and SMS?
It depends on your audience location:
For Europe (GDPR): One checkbox with clear language stating consent for both channels is acceptable.
For US/Canada (TCPA): Best practice is to use two separate checkboxes – one explicitly for email and one for SMS – to ensure clear, unambiguous consent.
For both regions: Use separate checkboxes to meet both GDPR and TCPA requirements.
Why was my toll-free number verification rejected?
Common reasons for rejection:
SMS opt-in checkbox is pre-selected (must be unchecked by default)
Missing required TCPA disclosures (message frequency, data rates, STOP/HELP instructions, privacy policy link)
Checkbox doesn't explicitly state SMS consent
Combined email/SMS checkbox without separate SMS language
Review your form, ensure checkboxes are unchecked by default, and include all required TCPA disclosures. Take a new screenshot and resubmit verification.
How do I import SMS subscribers from another platform?
Go to Audience → Imports → Import contacts from a file. Ensure phone numbers are in international format (+country code + number). When importing, check "Import phone numbers as subscribed to SMS channel."
Only import contacts who previously gave you explicit SMS consent – you must have records of their opt-in for compliance. Store consent records as custom properties.
Do European merchants need to follow TCPA rules?
No. TCPA applies only to SMS sent to US and Canadian customers. If you're based in Europe and only send SMS to European customers, you only need to follow GDPR (explicit consent, privacy policy link, clear unsubscribe method).
If you serve both EU and US/CA customers, follow both GDPR and TCPA requirements.
Can I pre-check the SMS opt-in checkbox to make signup easier?
No. SMS opt-in checkboxes cannot be pre-selected in Omnisend forms. Customers must actively check the box themselves to provide valid consent. Pre-checked boxes violate GDPR and TCPA compliance requirements and will cause toll-free number verification rejection.
Exception: WooCommerce checkout allows pre-selection.
If you have any questions, don't hesitate to reach out to our support team via in-app chat or [email protected].