Permissions for SMS and RCS: How to build a permission base that performs

If you want to succeed with SMS marketing and RCS marketing, permissions are not just a legal requirement - they are the foundation of performance. A permission base built right leads to higher engagement, stronger relationships and better results on mobile.

This article is for those who work in marketing or e-commerce and use - or are considering using - SMS and RCS for marketing messages.

SMS and RCS are among the most direct and personalised channels in your marketing mix. When a customer gives you permission to send marketing messages on mobile, they give you access to a channel where relevance, timing and clear value can translate directly into engagement, sales and loyalty.

In this article, we guide you on how to build a permission base for SMS and RCS that actually creates value. You'll get an overview of what permission marketing is - and isn't - how consent works across SMS and RCS, and which methods work best when you want to collect permissions in practice.

What is permission marketing?

Permission marketing is basically about only communicating with recipients who have actively agreed to hear from you. Instead of interrupting with unwanted messages, build relationships based on clear consent and a clear expectation of what the recipient will gain from being on your mobile list.

You're probably already familiar with permission marketing - for example, when you sign up for a newsletter or say "yes" to being contacted by phone by a company. The common denominator is that communication only starts when you have given your authorisation.

In practice, this means that SMS and RCS are not channels that you can just "adopt". They have to be earned. When a customer gives you permission to send marketing messages on mobile, they have made a conscious choice because they expect something valuable in return - for example, relevant offers, early access, inspiration, invitations or exclusive benefits.

For marketing and e-commerce, permission marketing is particularly effective because it creates a more engaged audience. Recipients are already interested in your brand, which creates optimal conditions for clicks, conversions and long-term loyalty. That's why the quality of your permissions is generally more important than the quantity.

Permission marketing is not just about what you can send. It's a strategic choice to communicate in a way that emphasises relevance, timing and value - especially when working with channels as personal as SMS and RCS.

What is a permission - and what is it not?

A permission is a specific authorisation from the recipient for you to send marketing messages on a specific channel - for example SMS, RCS or email. It is given voluntarily and with the expectation that the communication is perceived as relevant and value-adding. In practice, the terms permission, authorisation and consent are often used synonymously.

A permission is not a blank cheque to send anything, anywhere. Consent implies a clear expectation that you only use the channels the recipient has actively agreed to - and that your messages make sense to the recipient.

That's why permission in practice is as much about aligning expectations as it is about consent. The clearer you are about what the recipient is saying yes to and the better you deliver on it, the stronger the relationship will be. This applies whether you communicate via SMS, RCS or email.

It's also important to distinguish between the legal and the commercial. Legally, permissions are about whether you can send marketing on a given channel. Commercially, it's about whether the recipient wants to keep hearing from you. Here, relevance, timing and clear value are what determines whether your permission base grows over time.

A licence is therefore not a guarantee of engagement - but an opportunity. The better your messages match the recipient's expectations and interests, the stronger the results you can achieve with your permission marketing efforts.

SMS and RCS: Same consent, different expectations

When it comes to mobile consent, SMS and RCS are treated the same. If a recipient has given permission to receive marketing messages on their mobile, the consent applies to the channel they have agreed to - regardless of whether the message arrives as a classic SMS or RCS.

In practice, both RCS and SMS are typically sent via an SMS gateway where it is possible to handle broadcasts, cancellations and integrations in the same system.

However, this doesn't mean that the expectations for the two formats are the same. SMS is a familiar and simple format that most people associate with short, direct messages. RCS is more visual and interactive and more like an app experience. It affects how the recipient experiences your content - and what they expect to get out of subscribing.

RCS offers multiple ways to display products, emphasise messages and create engagement directly in the message. At the same time, it places greater demands on relevance and timing. The more content and visual space you have, the more important it is that the message is perceived as valuable to the recipient.

Therefore, it's a good idea to think of SMS and RCS as two different expressions of the same relationship. The consent is the same, but the experience is different. While SMS is great for short, time-critical messages, RCS allows for more inspiration and deeper engagement - without compromising the expectation of relevance.

In short: Same permission, different expectations. When you adapt your content to the format, you get more out of both SMS and RCS.

What the law says - in a nutshell

When we talk about permissions in marketing, it's ultimately marketing law that sets the framework. In general, however, you must have valid consent before you can directly contact the recipient with marketing messages.

Consent must be voluntary, active and informed. The recipient needs to know who is sending the messages, what channel is being used and that it is marketing. In addition, it should always be easy to withdraw consent - for example via an unsubscribe link in the message.

It's important to distinguish between marketing and service messages. Service and operational messages such as order confirmations, delivery updates and other necessary information do not require consent in the same way. It is only when the message has a marketing purpose that the consent requirement comes into effect.

However, we must emphasise that inMobile does not provide legal advice. This article is for guidance only and it is always your responsibility to ensure that you comply with applicable legislation. The rules can change over time, and in case of doubt, we recommend that you seek legal advice or stay updated via official sources such as the Danish Data Protection Agency's website, the Consumer Ombudsman's website or the Danish Marketing Practices Act.

With the legal foundation in place, you can focus on the most important thing: using your permissions correctly and creating value for those who have agreed to hear from you.

How to build your permission base

A strong permission base doesn't happen by accident. It's built where your customers are already engaged and where it makes sense for them to say yes.

Common to the most effective methods is that they link permission to a clear value and a natural situation in the customer journey. The closer you are to a purchase, an active choice or an existing customer relationship, the higher quality your permissions will be - and the better your SMS and RCS communication will perform.

There are many creative ways to collect permissions. Below we go through some of the most common and effective ways to build your permission base.

1. Customer clubs and loyalty programmes

Customer clubs and loyalty programmes are among the strongest sources of permissions. Customers don't just say yes to hearing from you - they actively choose to enter into a relationship with your brand.

When a customer joins a customer club, the expectation is already set: they want to receive relevant communication, special benefits and content that feels more exclusive than what everyone else gets. This makes the customer club an ideal place to collect permissions and create a foundation for increased customer loyalty.

At the same time, loyalty programmes give you a clear starting point for communicating value. It could be early access to sales, personalised offers, points status, invitations or product news. The clearer the link between permission and benefit, the stronger the quality of the permissions you collect.

An important point is that permissions in customer clubs often have a long lifespan. Members have already shown interest and engagement, which means that mobile communication here can be used more strategically and relationally - not just campaign-based. The result is typically higher engagement and fewer cancellations.

2. Competitions and polls

Contests and polls are an effective way to collect permissions because they combine low friction with high involvement. The user gets something here and now, while you get to quickly expand your permission base.

Competitions work particularly well for activating new audiences or creating awareness around campaigns, launches and events. Polls are better suited to existing customers and can provide insights into preferences and interests that can be used for segmentation later.

Competitions and polls are particularly relevant when you want to drive activity and quickly grow your permission base - especially as an integral part of a campaign where engagement is already a focus.

3. Pop-ups

Pop-ups are one of the most common methods of collecting permissions on a large scale - and for good reason. They are easy to implement and can be placed exactly where the user is already active on your website.

Pop-ups work best when they appear in a relevant context. This can be after a certain period of time, at scroll, at exit intent or in connection with specific pages or products. The better the timing, the more likely the user is to opt-in.

It's crucial that the pop-up is clear and easy to understand. The user should be able to quickly see what they get by signing up and what they agree to. Short, clear text and a simple choice makes it easier to make the decision without distracting from the experience.

4. Lead ads

Lead ads are an effective way to collect permissions because they make it easy for the user to sign up directly in the advert without having to leave the platform they are already on. The form is also often pre-filled with the user's details, which reduces friction and increases sign-up rates.

Also known as lead generation, it works particularly well on social media where the user is already in a mindset of browsing and inspiration. Lead ads are often used to offer something concrete - for example, competitions, early access, a benefit, a piece of content or participation in a campaign - in exchange for permission.

This also means that there will typically be a certain proportion of early cancellations. Some users sign up just to get the specific offer and then unsubscribe afterwards. It's a natural part of the mechanics of lead ads and something you should expect and plan for.

The task is therefore to use your SMS or RCS communication to show that there is a good reason to stick around and get more - even after the initial incentive has been redeemed.

Lead ads are particularly suitable when you want to scale your permission base quickly and reach new audiences who don't necessarily have prior knowledge of your business - and where volume and reach are more important than long-term relationships from first contact.

5. Checkout on the website

Checkout is an obvious place to collect permissions because the user is already an active customer and has taken a clear step in their relationship with your brand. Here, trust is typically higher than earlier in the customer journey and the context makes it natural to offer SMS and RCS sign-up.

Permissions at checkout are often used to keep the customer updated with offers, news or exclusive benefits after purchase. It can also be a way to invite the customer into a customer club or loyalty programme where mobile communication is part of the experience.

It's important that signing up at checkout is an active choice and not something that feels hidden or forced. A simple checkbox and a short explanation is often enough to make it clear what the customer is agreeing to - without disrupting the purchase flow or making the customer unsure of what they are agreeing to.

As a method, checkout typically provides high-quality permissions because they come from customers who have already shown purchase intent. This makes checkout particularly suitable if you want to build a permission base with a focus on existing customers and loyalty.

6. From email to mobile permission

Many organisations have already built a solid permission base on email. This makes email an obvious starting point for inviting customers to SMS or RCS as well - as a supplement, not a replacement.

At the same time, it's normal to experience a certain reluctance to give up your phone number, as mobile feels more personal than email for many. That's why the transition works best when it builds on an existing relationship where the recipient already knows your brand.

In practice, the transition can be done via emails where you invite the recipient to sign up for SMS or RCS to get faster messages, exclusive access or content better suited for mobile.

When the purpose is clear and the value is clear, many organisations find that the initial reluctance quickly disappears. The result is high-quality permissions because they build on existing engagement, trust and a conscious choice on the part of the recipient.

Use case: From email to mobile permission

At home and lifestyle store KAiKU, email has long been a central part of customer communication. Therefore, it was natural to build on the existing email permission when they wanted to expand their communication to SMS.

To get off to a good start, KAiKU sent a well-worded email to their email list, inviting recipients to also hear from them via SMS. The message was simple and focused on what you could expect to receive on mobile - including messages about special promotions, events and in-store customer nights.

The email achieved an open rate of 52.2% and 6.7% of those who opened the email chose to sign up to the SMS list. Overall, 3.5% of all recipients converted to mobile permissions, resulting in 240 new SMS permissions via email alone.

The case shows how email can act as an effective lever to build mobile permissions. By introducing SMS and RCS as a natural next step in the relationship, KAiKU managed to extend their communication to mobile.

Tips for your permission collection

When working to build a permission base for SMS and RCS, there is rarely one method that stands alone. The best results are achieved when multiple levers are combined and when permission collection is thought of as an ongoing part of the customer journey - not as a one-off activity.

Here are some of the tips we see recurring in companies that succeed with their permission collection.

#1 Make the value clear

Although the methods may be different, there is one common denominator: the user must quickly understand why it makes sense to say yes to mobile communication. It doesn't have to be complex, but it has to be concrete. The clearer the connection between signing up and what you get access to, the easier it is to make the decision.

#2 Collect in the right context

Timing matters a lot. Permissions work best when they are collected in situations where the user is already engaged - for example, after a purchase, during a campaign or as part of an existing relationship. It makes signing up more natural and less intrusive.

#3 Segment already at sign-up

If you can, it can be beneficial to segment your recipients already in the sign-up process. This can be by allowing the user to choose areas of interest or the type of messages they want to receive. This gives you better opportunities for targeted communication later on. But be careful not to make the registration unnecessarily complex.

Summarising

Permissions are the foundation of all effective SMS and RCS marketing. Not just as a formality, but as a prerequisite to comply with marketing law and drive engagement, relationships and long-term results on mobile.

If you want to succeed with SMS and RCS, the task is clear: Build your permission base where customers are already engaged and where it makes sense for them to say yes. This can be at checkout, via customer clubs, through lead ads, competitions or by inviting existing email recipients to mobile.

SMS and RCS are based on the same consent but used differently. SMS is great for short, direct messages, while RCS allows for more visual and engaging content. When you choose the format according to situation and purpose, you get more out of both channels.

The KAiKU case study shows that you don't have to start from scratch. Existing relationships - especially via email - are often the strongest starting point for building mobile permissions because trust is already established.

In short: Start with the relationships you already have. Make it clear why it makes sense to hear from you on mobile. And use SMS and RCS where they make a real difference. Then you don't just get a permission base - but a strong foundation for mobile marketing that can grow over time.