How to leverage SMS marketing program to increase return visits

Executive summary

SMS marketing delivers a 98% open rate and a 45% response rate, outperforming email by a factor of seven [SAP Engagement Cloud, 2026]. For venue operators, the challenge is not the channel itself - it is capturing verified, consented phone numbers at scale. Your Guest WiFi infrastructure is the answer. When a shopper, guest, or fan connects to your network, the captive portal becomes a data capture engine. Purple Engage captures verified phone numbers at login, links them to a device MAC address, and automates SMS campaigns triggered by specific visit behaviours. The result is a closed-loop attribution system: you send an SMS, the device returns to the venue, and the network confirms the visit. This guide walks you through the architecture, the compliance requirements, the deployment steps, and the business case.

Technical deep-dive

The data capture problem

Most venue operators have a significant gap between the number of visitors they receive and the number of verified contacts in their CRM. Anonymous footfall generates no revenue after the visit ends. The only way to close that gap in a physical space is to capture data at the point of connection.

The captive portal (a web page that users must interact with before accessing a public WiFi network) is the most effective tool for this. When a visitor connects to your SSID, the network controller redirects all HTTP traffic to the Purple splash page. Here, you request a phone number and present an explicit SMS marketing opt-in. This conscious-choice opt-in - where the checkbox is unticked by default - is a strict requirement under GDPR Article 7 and CCPA Section 1798.100.

Purple operates as a hardware-agnostic cloud overlay, integrating directly with Cisco Meraki, HPE Aruba, Ruckus, Juniper Mist, Ubiquiti UniFi, Cambium, Extreme Networks, and Fortinet. Regardless of your underlying hardware, the data capture process is consistent across your entire estate.

Authentication and verification architecture

The authentication flow relies on RADIUS (Remote Authentication Dial-In User Service), the networking protocol that provides centralised authentication. When a device associates with the SSID, the access point sends an authentication request to the RADIUS server. Purple acts as the identity layer, processing the request and returning an accept or reject signal.

To prevent database degradation from fake numbers, Purple enforces SMS verification during the login process. The platform sends a one-time passcode to the provided number. The user must enter the code to gain internet access. This step eliminates inaccurate data at the source and ensures that every phone number in your Purple Engage database is verified and reachable.

Once authenticated, Purple stores the verified phone number alongside the device MAC address (the unique identifier assigned to a network interface controller). This pairing is the foundation of deterministic tracking - the ability to attribute physical visits to specific marketing campaigns based on definitive identifiers rather than probabilistic models.

Segmentation and automation

Raw data is not a marketing programme. The value comes from segmentation and automation within Purple Engage. The platform allows you to build audience segments based on visit frequency, dwell time, last visit date, and venue location. You can then configure automation rules that trigger SMS messages when a visitor meets specific criteria.

For example, a shopper who visited a Retail location three weeks ago but has not returned can be placed in a "lapsed visitor" segment. Purple Engage automatically sends an SMS with a time-limited offer when the lapse period is reached. The message includes a trackable link, and when the device MAC address is detected at the venue again, the return visit is logged and attributed to that specific campaign.

This integration with WiFi Analytics closes the attribution loop that digital advertising cannot. You are not measuring clicks - you are measuring physical footfall.

Implementation guide

Deploying an SMS marketing programme requires four coordinated steps.

Step 1: Configure the captive portal. In the Purple dashboard, set up your splash page to request a mobile number. Ensure the SMS opt-in checkbox is unticked by default. Add clear, plain-language consent text that explains what the visitor is agreeing to. This text must be specific: state the type of messages they will receive and how frequently.

Step 2: Enforce SMS verification. Enable the one-time passcode flow in Purple Engage. This is non-negotiable. Without verification, users will enter fake numbers to access the WiFi, and your database will be worthless within months.

Step 3: Define your automation triggers. Map out the key visitor behaviours you want to respond to. Common triggers include: first visit (welcome message with a discount), lapsed visit after 14 days (re-engagement offer), and high-frequency visitor (loyalty reward). Configure these rules in Purple Engage before you go live.

Step 4: Segment before you send. Never send a broadcast message to your entire database. Use Purple Engage's segmentation tools to target specific groups. A first-time visitor at a Hospitality venue needs a different message than a guest who has stayed five times.

Best practices

The following principles are drawn from deployment data across Purple's 80,000+ live venues.

Respect frequency limits. Data from SAP Engagement Cloud shows that 53% of consumers opt out due to over-frequency. Limit promotional SMS messages to a maximum of once every 14 days per user. Use Purple Engage's frequency capping to enforce this automatically.

Provide immediate value. Consumers opt into text messages for specific, practical reasons: exclusive discounts (58%), early access to deals (45%), and appointment reminders (76%) [Sakari, 2025]. Every SMS you send must offer tangible value. If it does not, cut it.

Integrate channels. Brands that integrate SMS into their omnichannel strategies see a 47.7% lift in customer engagement [Omnisend]. Use email for detailed content and newsletters. Reserve SMS for urgent, time-sensitive offers where the 98% open rate and 90-second read time work in your favour. For more on this, see How to leverage SMS marketing softwares to increase return visits .

Time your messages correctly. SMS is an immediate channel. A message sent at 7am on a Sunday will generate opt-outs. For retail, Thursday afternoon sends targeting weekend shoppers consistently outperform other timing windows. For Transport hubs, post-journey messages sent within 30 minutes of departure perform well.

Test message copy. Short, direct messages outperform long ones. A message under 160 characters (one SMS segment) avoids carrier splitting and reduces cost. Include a clear call to action and a trackable link. A/B test your copy in Purple Engage using small audience splits before rolling out to the full segment.

Troubleshooting and risk mitigation

High opt-out rates. The primary cause is over-frequency. If your opt-out rate exceeds 3.5% per send, reduce frequency immediately and review your segmentation. Ensure you are not sending SMS and email on the same day to the same user.

High bounceback rates. This indicates fake or inactive numbers in your database. The fix is to enforce SMS verification at the Captive Portal. If you have an existing database without verification, run a re-engagement campaign and remove all numbers that do not respond within 30 days.

GDPR compliance failures. The most common failure is an ambiguous consent mechanism - for example, a pre-ticked opt-in box. Purple's captive portal templates are designed with GDPR-compliant, unticked checkboxes by default. Do not modify this behaviour. Retain consent records, including the timestamp and the exact consent text shown, for a minimum of three years.

Low delivery rates. If your delivery rate drops below 90%, check your sender ID registration. In the UK and EU, unregistered sender IDs are increasingly filtered by mobile carriers. Register a named sender ID (for example, "PremierInn" rather than a random short code) to improve deliverability.

Attribution gaps. If you cannot reconcile SMS sends with return visits, check that MAC address logging is enabled in your Purple network configuration. Some enterprise hardware vendors disable MAC address randomisation detection by default. Verify this setting on Cisco Meraki, HPE Aruba, and Ruckus deployments specifically.

ROI and business impact

SMS marketing delivers between $21 and $41 ROI for every $1 spent under conservative estimates [Upcity, 2024]. Some seasonal campaigns report returns up to $71 per dollar [Attentive, 2024]. For venue operators, the more relevant metric is incremental return visit rate.

Purple's deterministic tracking allows you to calculate this directly. If you send a targeted SMS to 1,000 lapsed visitors and 150 return within seven days, you can calculate the exact revenue generated against the cost of the SMS segment. This is far superior to probabilistic ad attribution, which relies on modelled estimates.

A typical 200-site retail chain deploying Purple Engage across its estate can expect to build a verified SMS database of 15,000 to 50,000 contacts within the first six months, depending on daily footfall and portal conversion rates. A well-segmented re-engagement campaign to lapsed visitors typically achieves a 12% to 18% return visit rate within seven days of send.

Brands that integrate SMS into omnichannel workflows alongside email see a 47.7% lift in customer engagement [Omnisend]. SMS plus email produces approximately 56% higher ROI than email alone [Sakari, 2025]. The channels amplify each other: email handles depth, SMS handles urgency.

References

[1] SAP Engagement Cloud. "Customer Loyalty Index 2025." 2026. [2] Sakari. "SMS Marketing Statistics: Data-Backed Insights for 2025-2026." 2025. [3] Upcity. "SMS Marketing Survey." 2024. [4] Attentive. "2024 Consumer Trends Report." 2024. [5] Omnisend. "Omnichannel Marketing Statistics." 2024.