Skip to main content

SMS Consent

SMS consent is a verified agreement in which a consumer explicitly gives a business permission to contact them via text message.

Text marketing is one of the most direct channels a brand can use. People read texts within minutes of receiving them, and open rates consistently outpace nearly every other digital channel. For businesses seeking to connect with customers in a fast and personal way, that kind of access is genuinely valuable.

But that access comes with responsibility. SMS is an intimate channel — your messages land in the same inbox where people receive texts from their family and friends. That makes consumers protective of their text inboxes, and both regulators and mobile carriers take that protection seriously.

Before you send a single promotional text, you need clear, documented permission from every person you're messaging. Brands that skip that step risk legal exposure and burning the very audience they're trying to reach. The good news is that when consent is collected and managed correctly from the start, it becomes the foundation of one of your strongest marketing channels. Keep reading to learn what SMS consent is, why it matters legally and strategically, and how to collect and maintain it the right way.

What is SMS consent?

SMS consent refers to a customer's explicit, documented agreement to receive messages from a business. The legal standard in the United States is known as "express written consent," which requires the customer to take a deliberate, affirmative step to sign up. That step needs to be clearly tied to the specific type of messages they're agreeing to receive, and it must be documented in a way you can verify later if needed.

This is one area where SMS differs significantly from email. Email marketing operates under regulations that allow for broader interpretations of permission, including some implied consent scenarios. SMS is held to a higher standard because it's a more personal channel. Regulators and mobile carriers both recognize that a text message carries a different level of intimacy than an inbox message, and they regulate it accordingly.

One of the most common mistakes businesses make is assuming that having a customer's phone number is the same as having their permission. It isn't. Purchasing a contact list, using a number from a past transaction, or pulling a number provided during an unrelated sign-up does not constitute legal consent to send SMS messages for marketing purposes. The customer must actively choose to subscribe clearly, voluntarily, and in a way you can document.

Why is it important to obtain consent before sending SMS messages?

Proper consent isn't just a legal formality. It directly affects deliverability, brand reputation, and the quality of your results. Here's why it deserves serious attention:

  • Legal compliance: The TCPA carries fines of $500 to $1,500 per unsolicited text in the United States, and violations can escalate into class-action lawsuits with significant financial consequences. For businesses reaching EU customers, the GDPR applies similar protections. Failing to follow text message laws is an ongoing liability.
  • Carrier deliverability: Mobile carriers like AT&T and Verizon actively monitor sending behavior and filter out messages from brands that don't follow proper protocols. If your account gets flagged, your messages may simply never arrive, no matter how relevant or well-written they are.
  • Brand trust: Texting someone who didn't ask to hear from you is intrusive. It drives high opt-out rates, spam complaints, and the kind of brand friction that's difficult to bounce back from. People guard their text inboxes, and showing up uninvited is one of the fastest ways to lose a customer's goodwill.
  • Higher engagement: Subscribers who actively signed up to hear from you are high-intent by nature. Consent-based lists consistently outperform purchased or scraped ones, with stronger open rates, better click-through rates, and more conversions.

Types of SMS consent

Consent varies depending on what kind of messages you're sending. Here are the three main categories to understand:

  • Transactional consent: This covers non-marketing updates, such as shipping notifications, appointment reminders, order confirmations, and similar messages. Because these are tied directly to an action the customer already took, the consent requirements are less strict than they are for marketing content.
  • Promotional consent: Any marketing content, whether promotions, sales, product announcements, or newsletters, requires express written consent. The customer must clearly and specifically agree to receive marketing texts from your brand. A general terms-of-service checkbox buried at the bottom of a sign-up form won't qualify.
  • Double opt-in: After someone opts in, a confirmation text is sent asking them to verify their intent — typically by replying with a word like "YES." This extra SMS opt-in step confirms the number is valid and that the person who provided it genuinely wants to be on your list. Double opt-in is one of the most reliable ways to keep your list clean and consent records solid.

How to collect SMS consent

There's no single right way to build a compliant list. Here are the most common and effective methods:

  • Signup forms: Pop-ups and dedicated landing pages with a separate SMS field are straightforward and easy to automate. Every form must include clear disclosure language that includes what kind of messages the subscriber is signing up for, how often they'll arrive, and how to unsubscribe.
  • Keywords: Campaigns like "Text JOIN to 12345" are widely used on social media, physical signage, and broadcast advertising. They lower the barrier to entry for customers and are simple to track and manage on the back end.
  • Checkout subscription checkbox: Adding a subscription option at the point of purchase captures customers at a moment when they're already engaged and transacting with your brand. The checkbox must always be unchecked by default. A pre-selected box does not meet SMS compliance standards and won't hold up to scrutiny.
  • QR codes: A scannable code that opens a pre-filled text message removes friction from the sign-up process entirely. This format works well in retail environments, at live events, or on printed materials where typing a number isn't practical.
  • The must-haves: Every consent collection point — regardless of format — needs to clearly state the program name, how often messages will be sent, a note that message and data rates may apply, and links to your Terms of Service and Privacy Policy. Missing any of these elements can put you out of compliance even when the customer did intend to sign up.

Best practices for maintaining compliance

Your customers simply don't want to receive SMS messages they didn't ask for. But collecting consent is only half the job. These best practices help you stay compliant and protect your list over time:

Keep records for SMS compliance

Document the timestamp, IP address, and source for every subscriber at the moment they sign up. If your consent is ever challenged, you must be able to produce that information quickly. Most reputable SMS platforms capture this data automatically, but it's worth verifying yours does.

Provide easy SMS opt-outs

Proper SMS consent also means managing opt-out requests to ensure you don't text someone who has decided they no longer want to hear from your business. Every message should include a clear way to unsubscribe. "Reply STOP to cancel" is the industry standard.

Honoring those requests promptly isn't optional; it's required by law and good practice for keeping your list healthy.

The same SMS consent language you used to bring subscribers in should carry through to how you let them leave.

Respect SMS quiet hours

Texting subscribers late at night or early in the morning is intrusive and may violate state-level regulations. Always respect SMS quiet hours, accounting for the recipient's time zone, and keep your sending window to roughly 8 am to 9 pm local time.

Message frequency is also important. Sending texts too often is one of the fastest ways to drive opt-outs, so stick to the cadence you promised when subscribers signed up. Message frequency varies depending on the timing of promotions or seasonal campaigns — just make sure any increase in volume still falls within what subscribers reasonably expected when they opted in.

Verify identity

Using double opt-in to confirm that the phone number belongs to the person who signed up helps prevent fraud, reduces undeliverable messages, and gives you a stronger legal footing if a subscriber ever disputes their consent.

How to get the most out of SMS consent

A compliant, permission-based list is a strong foundation. Here's how to build on it:

  • Integrate with email: Mailchimp's multi-channel tools let you sync SMS and email preferences across a single customer profile. This provides a unified view of how each person prefers to hear from you and makes coordinating cross-channel campaigns significantly easier.
  • Personalization: A high-intent subscriber list is an opportunity to be genuinely useful. Use what you know about each person, such as their purchase history, preferences, and browsing behavior, to send targeted, relevant texts rather than broad announcements. Segmented messages consistently outperform generic ones.
  • Automation: Set up a welcome text that triggers the moment someone subscribes. Reaching out while they're most engaged sets the right tone immediately and can drive real action right away. From there, automated flows for re-engagement, cart abandonment, and milestone moments can run largely on their own.

Building better connections with SMS

SMS consent is, at its core, about mutual respect. When you ask permission before reaching out, you're telling your customers that their attention has value and that earning it matters more than simply demanding it. That approach is what separates brands that build lasting SMS audiences from those that constantly cycle through new contacts because their current ones keep leaving.

A strong SMS program grows on trust. Subscribers who actually want your messages are worth far more than a large list of people who never asked for them. Prioritizing genuine permission, proper collection, and ongoing compliance is what makes your marketing efforts perform well. When the foundation is solid, everything built on top of it works better.

Mailchimp's SMS marketing tools are built to help you manage all of this in one place. From compliant sign-up forms and automated welcome sequences to opt-out management and list health monitoring, Mailchimp provides the infrastructure to grow a real, engaged audience without having to navigate the nuances of SMS consent on your own. Sign up for Mailchimp today. General - Inline article CTA - Sign up - Unlock the power of email + SMS