A proximity marketing upsell offers a customer the better version of what they are about to buy — the large instead of the medium, the premium seat, the drink with the hot dog — where and when they are choosing. Bluetooth beacons, Wi-Fi and GPS geofences can place a phone near that moment, but their offers have usually traveled through the brand’s app, and a one-time visitor has little reason to install it. LISNR’s Radius Web SDK lets the web page a customer already has open receive the offer as an ultrasonic tone from the venue’s speakers, once the customer allows microphone access. No native app needs to be installed on the customer’s phone.
You do not have to abandon the invitation to join or download. But research suggests you should give customers a reason to consider it before asking them to decide.
A customer can want your offer without wanting your app
Remember the last time you were on a city trip and were asked to download an app when all you wanted was two metro rides? A driver stopping for fuel and coffee at an unfamiliar convenience store faces the same decision. So does the one-time visitor to your stadium who joined a friend for the game while in town.
These are your transient users. The first time you encounter them they are in a transactional mode. They may want a fare, an offer, or a place in your loyalty program without knowing when they will return. You want them to take that next action. Requiring an app download asks them to make a second decision before they have received the benefit of the first.
Transient customers are customers with an intention to buy from you and a limited reason to install your app.
Every additional click you make them take, loses you around 50% of remaining users
Mobile signups create a 30-45% drop-off per step per uxcam’s study from 2024. In practice, a forced hop from mobile web into the App Store—redirect, store page, authentication/FaceID, download wait, open, re-navigation—effectively adds 4-6 steps. At typical per-step loss rates of 15-30%, that sequence can easily cut your completing cohort in half or worse compared to a single-page mobile web checkout.Every time you ask the user click you lose half of them.
According to Andrew Chen’s growth analyses each additional required click or step often cuts the audience by roughly half, and that asking users to download an app can cause around 80% of them to bounce at that step.
When you, again, layer these 4-6 extra steps (store redirect, authentication, download, open, re‑navigation) on top of a mobile web flow that might otherwise have 1–2 steps, basic funnel math implies a 2-5x higher effective acquisition cost versus completing the same action on the open web.
To increase revenue you should avoid turning purchase intent into an installation decision. Because for a visitor who may never return, those are very different propositions.
Proximity marketing upsells stalled at the app install
Upselling by location is an old promise. In the beacon wave of the 2010s, retailers put Bluetooth transmitters in their aisles to push offers to phones passing by. A March 2026 retrospective in CPG Matters lists what it took for one of those offers to arrive: “a shopper needed to have the retailer’s app installed on their phone, have Bluetooth enabled, have location permissions granted, and have push notifications turned on. Most shoppers did none of these things.” (Wolpow, 2026)
The one route around the app closed in 2018. Android’s Nearby Notifications could show beacon content to phones without the brand’s app, and Google stopped serving them on December 6, 2018, after “a significant increase in locally irrelevant and spammy notifications” (Android Developers Blog, 2018).
The radios could detect phones. What failed was the channel. Every offer depended on an app the customer had not chosen to install, and that shut out the transient customers, the ones most open to a one-time upsell.
Give customers a reason to say “Yes!” before you ask for more
Upselling to transient customers requires capturing their attention during highly specific moments.
Imagine a visitor sitting in your stadium for one game with a friend. She has your matchday page open after checking the lineup. Now she is watching the field, phone in hand. A screen near their section shows a hot-dog-and-drink deal at the concession stand. She misses it.
The venue’s sound system is also sending the offer’s reference through a Radius tone. Her open page receives it and plays on her device’s screen. The offer she missed on the stadium screen is now on the phone in her hand.
She hadn’t planned to buy food, but now the offer makes the walk to the concession stand worthwhile. She taps to claim it.
“Download our app to redeem.”
She hesitates. A meal deal has become a request to install software for a venue she may never visit again.
You already had a customer on your website, sitting in your stadium. You got her attention and gave her a reason to make another purchase. Now you risk losing that purchase to a decision she did not come to make.
The offer gave her a reason to get up from her seat. Let her redeem it through the browser while she has that reason to act.
This is the upsell proximity marketing has promised since the beacon years, a relevant offer at her seat while she can still act on it. What kept it from reaching her was the app it required.
The driver stopping for fuel on a long trip presents a similar opportunity. They may already have your menu open on their phone. An offer for a sandwich with their coffee could give them a reason to add something to their purchase. The opportunity is to make that offer relevant to their visit, and let them act on it without first deciding whether they want your app.
What happens when that browser visit reaches your door?
In Top 4 Ways Progressive Web Apps Are Quietly Redefining Our Relationship with Software, we explored how software is becoming something people can use in the moment, with less effort up front.
The next step is connecting that browser experience to the store, vehicle, or service physically in front of them, not sending them away to an app store.
With Radius Web SDK you reach your customer in the web browser
A progressive web app can run directly in the browser. Customers can open a link, use the service, and close the page. They do not have to agree to install a different kind of app before they can participate.
Loyalty and installation are separate decisions
Starbucks illustrates the distinction. In its 2018 PWA presentation, Starbucks described extending ordering ahead, mobile payment, and Rewards engagement across the web and multiple devices. Its US rewards program allows customers to join through the website or web app. They need an account to enroll, but they do not need to download the native app to join.
The visitor at your stadium just as the traveler buying breakfast can decide whether today's offer makes enrollment worthwhile. An app download is another decision, one that repeat visits may eventually justify.
Downloading and installing the native app is a separate choice, a second commitment the customer may not be ready to make. Defer that invitation until they have received your service and have a reason to come back. By then, the convenience of the app and the benefits of using it regularly may be worth the additional commitment.
For other brands, the lesson is to make participation available before asking for a place on the customer’s phone. A loyalty program can welcome new members through the web. Existing members can sign in there, too. And you can offer a guest experience for someone who simply wants to make a purchase. The browser gives the business room to design each path around the value it offers. With Radius Web SDK, that experience can also communicate with nearby devices.
Why an extra Web SDK? The iPhone has NFC and Bluetooth but Safari limits access
Sure, your phone has NFC and Bluetooth, but not all web browsers i.e., Safari, provide the web interfaces needed to communicate directly with nearby devices. That matters when you want to pass your current offer to the customer’s web browser, but their browser can’t receive your data.
Radius uses ultrasound for device-to-device communication. Its Web SDK lets a web page receive Radius tones through the microphone built into the customer’s phone.
The browser makes participation possible without an app download. Just as with the existing Radius SDK you can now offer a comparable user experience with the new Web SDK.
The open page can respond to your customers’ surroundings
At a physical location, that experience can become more useful when the web page receives information from nearby equipment.
A display can pass the reference for the offer it is showing to a customer’s open page. With LISNR’s Radius, a compatible speaker carries that reference as a tone and the phone receives it through its microphone.
- At your stadium, that connects the offer on the screen to the guest’s matchday page.
- At your retail location, it can connect an offer on a display to the product catalogue or menu the customer has open in their browser.
Now return to our stadium visitor. It is a screen near her section that shows the hot-dog-and-drink deal, but she is watching the field and misses it. The venue has connected its audio equipment to its web experience through Radius. On her open matchday page, she selects the option to receive offers from the venue. The page explains that it needs microphone access to receive a signal, and she grants permission.
A compatible speaker plays a short Radius tone carrying the offer’s reference. Her browser decodes it, and the venue’s web application brings up the deal and where to redeem it. She walks to the concession stand, follows the venue’s redemption process at checkout, and returns to her seat with food. The page she opened for the lineup has helped turn the offer into an additional purchase.
The venue supplies the local information. When its promotion changes, the same active page can receive a different reference. A venue can use a common matchday page while its screens and audio equipment supply the current offer.
The venue integrates the SDK with its offer system, checks its audio hardware and supported browsers, and controls eligibility and redemption. The customer’s page stays active while receiving. For this guest offer, neither membership nor an app download is required. But if you choose that the offer requires membership, then sign-in or enrollment can happen on the web, too.
Your proximity upsell stays welcome when the customer controls each step
Make the offer worth the walk. The stadium deal works because it is something she wants, a short walk from her seat. Relevance also protects the channel. Irrelevant, spammy notifications are what ended Android’s beacon notifications for phones without the brand’s app.
Ask for the microphone when the customer asks for offers. The visitor chooses to receive offers from the venue; only then does the page request microphone access and explain why. A customer who declines should still be able to use the page for everything else.
Let the customer redeem where the offer arrived. “Download our app to redeem” turns an upsell into an installation decision. Keep redemption in the browser, along with sign-in or enrollment when an offer requires membership.
Let your systems choose the offer. The tone carries a reference for the place and the offer. Your offer system decides what each customer sees, so a member who signs in can get an upgrade that fits their purchase history while a guest sees the general offer.
Research indicates: Let the experience earn the next commitment
Your visitor is back in her seat with her food. She received the offer, redeemed it, and got on with the experience she came to enjoy. Downloading your app was never part of the bargain.
Now your invitation can start with something she has experienced instead of just a promise of what she might receive after signing up.
The question changes from “Will you join so you can enjoy this offer?” to “You enjoyed this. Here is what joining makes possible next.”
For a loyalty program, that might mean member offers on future visits. For an app, it might mean useful features for customers who expect to return regularly. In either case, explain the additional benefit, not just the action you would like the customer to take.
Joining your loyalty program and installing your app remain separate choices. A visitor can decide that membership is worthwhile without deciding that your app deserves a place on her phone. Give each invitation its own reason to say yes.
This is not simply about moving the same signup request to the end of a transaction. It is about changing what supports the request. The customer has experienced something worthwhile and now your invitation shows how continuing the relationship could make it more worthwhile.
Research on relationship marketing suggests that genuinely helpful benefits can generate gratitude and reciprocal behavior. But a customer does not have to feel indebted to want the relationship to continue. Having experienced something worthwhile, they may simply see a reason to receive more of it.
Some visitors will still only want today’s purchase. That is not a failure of the experience. They should be able to enjoy the visit they have already chosen without agreeing to a relationship they do not need.
This is how you make the next commitment a way to receive more value instead of an obstacle to the value you have already offered.
Reach customers beyond your app with Radius Web SDK
A customer who declines your app has not necessarily declined your offer. Radius Web SDK lets your web page receive signals from nearby equipment, giving you a way to connect an offer to the customer’s visit without requiring an app download.
For the visitor in your stadium, that can mean receiving a relevant offer, buying something she wants, and enjoying the rest of the game.
For the driver stopping at your forecourt, it can mean discovering a sandwich-and-coffee offer on the menu page they already have open, picking up breakfast, and getting back on the road. They get more from the stop without having to download an app for a place they may never visit again.
Whether they ever join your loyalty program or download your app is a separate decision and not the measure of whether you served a customer well today.
Both experiences create an opportunity for an additional purchase. Neither needs to result in a loyalty membership or an app download to be worthwhile—for the customer or for your business. But each gives you something to build on: the customer has experienced the value of your offer. Your next invitation can explain what continuing the relationship would add.
Which customer interaction are you still making conditional on an app download?
Start with one in-person offer customers currently need your app to redeem. Use a Radius Web SDK trial to explore how they could discover and redeem it through your web experience instead.
Let them receive the benefit first. Then give interested customers a specific reason to join your loyalty program or download your app.
The next commitment should extend a good experience. Start that experience in the browser with Radius Web SDK.
Chen, Andrew (2024). Every time you ask the user to click you lose half. https://andrewchen.com/every-time-you-ask-the-user-click-you-lose-half/
Palmatier, Robert W., Jarvis, C. B., Bechkoff, J. R., & Kardes, F. R. (2009). The Role of Customer Gratitude in Relationship Marketing. Journal of Marketing, 73(5), 1-18. https://doi.org/10.1509/jmkg.73.5.1
Wolpow, Scott. (2026, March 23). A Look Back at Beacons: How a Promising In-Store Marketing Tool Got Lost in the Aisle. CPG Matters. https://www.cpgmatters.com/article/look-back-beacons-how-promising-store-marketing-tool-got-lost-aisle
Android Developers Blog (2018, October 25). Discontinuing support for Android Nearby Notifications. https://android-developers.googleblog.com/2018/10/discontinuing-support-for-android.html