How to leverage SMS marketing agency to increase return visits

Welcome to the Purple technical briefing series. Today we are talking about one of the most underused tools in the venue operator's marketing stack - SMS. Specifically, how you use your guest WiFi infrastructure to build a verified, consented phone number database, and then how you work with an SMS marketing agency to turn that data into return visits. I am going to take you through the architecture, the compliance requirements, the campaign mechanics, and the real-world numbers. Let's get into it. First, let's set the scene. You run a hotel, a retail chain, a stadium, or a conference centre. You already have guest WiFi deployed. Guests connect every day. But right now, most of that connection data is sitting idle. You know how many people connected. You might know their email addresses. But you probably do not have their mobile numbers - and even if you do, you may not have the right consent to market to them via SMS. That is the gap we are going to close today. Here is why SMS matters more than any other channel right now. Open rates for SMS sit at 98 percent, according to multiple industry studies. Email averages around 20 percent. Response rates for SMS campaigns average 45 percent, compared to 6 percent for email. And the ROI figures are striking - businesses report between 21 and 41 dollars returned for every dollar spent on SMS, with some seasonal campaigns hitting 71 dollars per dollar. These are not marginal improvements. They are a different order of magnitude. So how does guest WiFi become your SMS data engine? Let's walk through the architecture. When a guest connects to your WiFi, they pass through a captive portal - that is the branded login page they see before they get internet access. Purple's captive portal, deployed across 80,000 venues globally, can collect a phone number at that login step. The key word here is consent. Under GDPR in the UK and Europe, and CCPA in California, you cannot simply collect a phone number and start texting people. You need explicit, freely given consent for marketing communications. The consent checkbox must be separate from the WiFi access terms. Tying marketing consent to WiFi access is not valid consent under GDPR - the ICO has been clear on this. What Purple does is present a separate, clearly worded opt-in at the login screen. Something like: "Tick here to receive exclusive offers and updates by SMS." That consent event is timestamped, stored, and linked to the guest's profile. Purple is ISO 27001 certified, GDPR and CCPA compliant, and B Corp certified - so the data handling meets the standards your legal team will ask about. Now let's talk about the technical integration between Purple Engage and your SMS marketing agency. Purple Engage is the top-tier plan in Purple's guest WiFi stack. It sits above Connect and Capture. With Engage, you get automated journey triggers, CRM integration via over 400 connectors, and the ability to push verified, consented phone numbers directly into your SMS platform of choice. Whether your agency uses Attentive, Klaviyo, Twilio, or a bespoke SMS gateway, Purple's API layer handles the data transfer. The phone numbers arrive pre-verified and pre-consented, which means your agency does not need to run a separate opt-in campaign from scratch. You are starting from a warm, verified list. Purple works hardware-agnostically across Cisco Meraki, HPE Aruba, Ruckus, Juniper Mist, Ubiquiti UniFi, Cambium, Extreme, and Fortinet. You do not need to rip and replace your existing infrastructure. Purple sits as a cloud overlay on top of whatever access points you already have deployed. Let me give you a concrete example from hospitality. A mid-scale hotel group with 12 properties deploys Purple Engage across all sites. At login, guests enter their mobile number and tick the SMS marketing opt-in. Within 30 days, the group has collected 8,000 verified, consented mobile numbers. They brief their SMS marketing agency to run a re-engagement campaign targeting guests who stayed more than 60 days ago. The agency segments the list by property, by visit frequency, and by average spend. They send a personalised SMS: "Hi Sarah, it's been a while since your last stay at [Property Name]. Book direct this weekend and get 15 percent off." The campaign achieves a 34 percent click-through rate and drives a 22 percent uplift in direct bookings over the following four weeks. The hotel avoids OTA commission on those bookings - at an average commission rate of 15 to 20 percent, the saving per booking is significant. Now let's look at retail. A fashion retailer with 40 stores uses Purple to capture shopper phone numbers at WiFi login. Their SMS marketing agency segments the list by store location and purchase history, synced from the retailer's CRM via Purple's connector library. When a new collection drops, the agency sends a geo-targeted SMS to shoppers within five miles of each store. The message includes a unique discount code trackable back to the SMS campaign. The retailer sees a 19 percent redemption rate on the codes - significantly above their email campaign benchmark of 4 percent. Return visit frequency increases by 28 percent among SMS subscribers compared to non-subscribers over a six-month period. Let's talk about implementation pitfalls, because there are several that will cost you time and money if you hit them. The first is consent architecture. I said this already but it bears repeating - do not bundle SMS marketing consent into your WiFi terms of service. Keep it separate, keep it optional, keep it clearly worded. Your SMS marketing agency will thank you, because a clean consented list outperforms a large dirty list every time. The second pitfall is frequency. Around 53 percent of SMS unsubscribes are triggered by over-messaging, according to consumer research. Work with your agency to set a frequency cap - typically no more than two to four messages per month per subscriber. More than that and your opt-out rate climbs, which damages your sender reputation with the SMS gateway. The third pitfall is attribution. If you cannot measure return visits driven by SMS, you cannot prove ROI to your board. Make sure your agency uses unique tracking links, UTM parameters, or unique discount codes on every campaign. Purple's analytics dashboard shows you return visit rates by guest segment, so you can cross-reference WiFi reconnection data with SMS campaign sends. If a guest receives an SMS on Tuesday and reconnects to your WiFi on Thursday, that is a measurable return visit attributable to the campaign. The fourth pitfall is data hygiene. Phone numbers change. People switch numbers. Run a monthly validation pass on your SMS list to remove bounced numbers and update records. Purple's Engage platform flags inactive profiles automatically, which helps keep your list clean without manual effort. Now for a rapid-fire Q and A on the questions we hear most often. Can I use SMS for event-day communications at a stadium? Yes - and it is one of the highest-performing use cases. Fans connect to WiFi on arrival, opt in at the portal, and you can send real-time offers for merchandise, food and beverage, or post-match promotions within hours of the event. Do I need a dedicated SMS marketing agency or can I run campaigns in-house? Either works. Purple Engage has built-in journey automation for basic triggered campaigns - welcome messages, re-engagement flows, birthday offers. For more complex segmentation and creative, an agency adds value. Many operators start in-house and bring in an agency once the list reaches a meaningful size, typically around 5,000 subscribers. What is the minimum viable list size to start SMS campaigns? Most agencies recommend at least 1,000 verified numbers before running a broadcast campaign. Below that, the statistical significance of your results is too low to optimise from. Focus on building the list first. Is SMS compliant with PECR in the UK? Yes, provided you have explicit prior consent for marketing. The Privacy and Electronic Communications Regulations apply to SMS marketing in the UK, and the consent captured through Purple's portal meets PECR requirements when configured correctly. To wrap up - here are the five things to take away from today. First, your guest WiFi is already collecting the data you need. The question is whether you are capturing phone numbers with proper consent at the login step. Second, SMS outperforms email on every engagement metric - 98 percent open rate, 45 percent response rate, and ROI between 21 and 41 dollars per dollar spent. Third, Purple Engage connects your WiFi data directly to your SMS marketing agency's platform via API, with verified, consented numbers that are ready to use. Fourth, compliance is not optional - separate consent, frequency caps, and clean attribution are the three pillars of a sustainable SMS programme. Fifth, measure return visits through WiFi reconnection data cross-referenced with campaign sends. That is your proof of ROI. If you want to see how this works in practice for your venue type, speak to the Purple team. We have deployed this architecture across hospitality, retail, transport, and events - and the data from 440 million logins in 2024 gives us a clear picture of what works. Thanks for listening.