Installable store (PWA) and push notifications: permission, frequency and what to send

Most people who visit your store do not buy, do not register and do not subscribe to the newsletter. They look at two products and leave. You have neither their email address nor their phone number, so there is no way to remind them of anything.

Web push notifications are a channel for those people: an alert that appears in their browser or on their phone, sent by your store, with their permission. And an installable store (PWA) means your website can be added to the home screen and opened like an app, with no app store involved.

What a PWA is

A Progressive Web App is a website that the browser lets you install. It needs three things:

• HTTPS. Without a certificate there is no PWA and no push.
• A manifest: a file with the store name, icons and colours.
• A service worker: a script that the browser keeps registered and that receives notifications even when the store is not open.

For the customer, the result is an icon on their phone that opens your store full screen, without the browser bar. For you, it means being on their home screen alongside the apps they use.

How a push notification works

1. The visitor agrees to receive alerts. The browser generates a unique subscription.
2. Your store saves that subscription, encrypted with its own key pair (the VAPID keys).
3. When you want to send something, the store encrypts the message and hands it to the browser's push service (Google's for Chrome, Mozilla's for Firefox, Apple's for Safari).
4. The browser receives it and displays it, even if the store is closed.

An important detail: subscriptions are tied to those keys. If you switch tools and lose the keys, you lose all your subscribers. When you choose how to do it, make sure the list and the keys belong to you and can be exported.

Asking for permission: you only get one chance

This is the costliest mistake. If the browser's native window asking for notification permission pops up as soon as someone enters the store, most people click «Block». And once blocked, the website cannot ask again: the visitor would have to go into the browser settings to unblock it, and they will not.

The right way is a two-step prompt:

1. First, the store's own message, in your design, explaining what you will send: «Shall we let you know when it is back in stock or drops in price?».
2. Only if they say yes is the browser window triggered.

And timing matters. Not on the first page, but when there is interest: after viewing several product pages, after adding to the cart, when scrolling through a product, on the page of an out-of-stock item.

Which messages work

The ones the customer asked for

• Back in stock for a product they wanted.
• Order status: shipped, out for delivery.
• Price drop on something they looked at.

Nobody sees them as advertising. They have the best open rates and cause the fewest unsubscribes.

The ones that recover a sale

• Abandoned cart, checking just before sending that it has not already turned into an order.
• Abandoned browsing: someone viewed the same product several times and did not add it. A reminder with the product and its current price.

Campaigns

A new arrival or a promotion, segmented: to those who have viewed that category, to those who have bought before, by language or by country. A campaign to the whole list for every promotion is the fastest way to empty it.

Frequency: how much is too much

There is no figure that applies to every store, but there are some rules:

• A cap per person, daily and weekly, adding up flows and campaigns.
• Spacing between marketing alerts: if someone received one a few hours ago, the next one waits.
• Quiet hours in the customer's time zone. Nobody wants an alert from a store at three in the morning.
• Automatic exit: anyone who buys stops receiving reminders about what they have already bought.
• Measure unsubscribes, not just clicks. If each campaign costs you more subscribers than it converts, you are sending too much.

Consent and data protection

The browser permission is one part; the other is how you process data. If you link the subscription to the registered customer and use what they have viewed for segmentation, say so in your privacy policy, record consent and make it easy to unsubscribe. When a customer asks for their data to be erased, their subscriptions must be deleted too.

An up-to-date technical base

Web push needs HTTPS, a modern browser and a scheduled task (cron) that sends whatever is pending. In old stores, with outdated PHP or without a certificate properly configured on every URL, the service worker does not register or the encryption libraries do not work. Having PrestaShop and PHP up to date is a prerequisite, not an extra.

Checklist

• HTTPS across the whole store.
• The store's own prompt before the browser permission, at a moment of interest.
• Transactional messages first: stock, order, price.
• Caps per person, spacing and quiet hours.
• Exportable keys and subscribers.
• Updated privacy policy and cascading deletion.
• Instructions for installing the store on iPhone.

How to solve it in PrestaShop

RKR Mensajería makes your store installable (PWA) and sends push notifications from your own domain with your own VAPID keys, with no Firebase and no fees. It first asks for permission with its own prompt (triggered by time, scroll, exit intent, adding to the cart or after several product pages viewed) and only then triggers the browser's. It comes with flows whose filters are checked before each step, such as the abandoned browsing template, and automations for order status, back in stock, abandoned cart, price drop and win-back, with daily and weekly caps, quiet hours and segmented campaigns. It measures messages sent, clicks and attributed revenue, exports the list with its keys and records consent with cascading deletion. On iPhone, it shows a guide to anyone who has not installed the store.