PWA-installable booking on your own server
PWA-installable booking: an app icon on the phone served from your own domain, with no app store, and what is deliberately not cached.
PWA booking is searched by two kinds of people. One wants customers to book from a phone. The other wants the front desk to run the diary from a tablet that behaves like an app rather than a browser tab. The second is the one this page is about, because the first is just a responsive website and every serious booking tool does it.
What a progressive web app is, without the marketing
A progressive web app is a website the browser lets you install. Add it to a phone or tablet home screen and it gets an icon, opens full screen with no address bar, and appears in the task switcher like anything else. Underneath it is still the same site served from the same server.
Three consequences follow, and they are the entire trade.
No app store. Nothing is submitted, reviewed, signed or resubmitted. A fix you deploy on your server is live on the tablet at the next launch, with no review queue between you and it.
No native platform features. No push through the platform's own channel on every device, no background execution, no hardware integrations beyond what the browser exposes. If your workflow needs a barcode scanner driver or an offline day, this is not that.
The install is per device, from the browser. Which is a feature in a business setting: the front-desk tablet installs it, and a member of staff on their own phone does not have to.
What the booking tools here actually do
Slotly installs to a phone or tablet home screen straight from the browser, as a full-screen app served from your own server, with no app store involved. So does its rota sibling Rostera, and the same layer runs across the catalogue.
Try the Slotly demo ↗Live, on sample data, no sign-up.
The deliberate design decision inside that is worth naming: **business data is never cached offline.** Nothing in the product keeps a local copy of appointments to display when the network is down. That means the app is unusable without a connection, and it also means what is on the screen is always live rather than plausible. For a booking diary, a stale copy is worse than an honest error message -- a receptionist looking at yesterday's availability will double-book with confidence.
What to look for
Served from your own domain. The icon on the tablet points at your server. No third-party shell, no vendor's app, nothing that stops working when somebody else's subscription lapses.
An honest statement about offline. Ask directly what is cached. A vague answer usually means something is, and you want to know which screens can lie to you.
A full-screen experience that is actually usable at tablet size. A desktop admin squeezed into a tablet viewport is technically installable and practically useless.
A separate customer-facing page. The public booking form is a normal responsive page that any customer opens from a link -- it is not the thing that gets installed, and it does not need to be.
No store dependency for updates. Which is what makes a same-day fix possible at all.
The limits, stated plainly
There is no native application in any app store, and there is not going to be one -- that is the trade, taken deliberately. Business data is never cached offline, so the app needs a connection. Slotly processes no cards, its calendar feeds run one way, and it runs one business per installation. Reminders wait on a cron line because the application runs no background jobs of its own, and that is as true of the installed app as of the browser tab, because they are the same software.
Questions people ask
Does the front desk need an app store account? No. The install happens from the browser on the device, and the icon is added to the home screen from there.
Does it work without a network? No. Business data is deliberately never cached offline, so a lost connection shows an error rather than a stale diary. That is the intended behaviour for a booking system.
Do customers install anything to book? No. The public booking page is an ordinary responsive page opened from a link. Installing is for the people running the diary.
Where to look next
The product page is Slotly for appointments and Rostera for the rota, each listing the installable layer alongside everything it deliberately leaves out. The side-by-side sets the booking half against the hosted services, and the alternatives page is one common starting point. For what those services charge -- including the ones whose mobile app is the reason for the higher tier -- read the observatory: each figure is quoted verbatim beside the date it was read and a link to the page it came from. Prices are on the observatory; read them on the date shown there.