Why an app is usually the problem
Every well-known chat service wants to be installed first. That means an app store account, an install that a device policy may forbid, an update that will nag you later, and a signup with a phone number or email address at the end of it. On a managed device you usually fail at the first step, and on a borrowed one you do not want to be signed in as yourself anyway. None of those steps exist here: the address is the application.
What actually loads
The chat is one HTML page of roughly 64 kB with the styling and the code inside it. It pulls in no external stylesheets, no font files and no third-party frameworks, so opening a room is essentially one request. That is why it comes up quickly on a slow school connection, on hotel wifi and on an old phone, and why it keeps working on browsers a few years behind the current one.
Nothing to sign in to
There is no account, so there is nothing to be signed into on a shared computer and nothing to forget to sign out of. You choose a nickname when you arrive, and when you close the tab that is the end of it. On a machine that is not yours, that is the difference between chatting and leaving your identity behind in a browser profile.
The honest limit: a filter can still block this
It is worth being straight about this, because a lot of sites in this category are not. Having no app to install gets you past a software restriction, but it does not get you past a network filter. A school or company network can block any domain it likes, and if it filters by category then a chat site is exactly the sort of thing that category contains. If chatinbrowser.com does not open on your network, that is almost certainly why, and there is nothing on this end that changes it. We are not going to sell you a workaround for your school's network.
Where this genuinely helps
The realistic cases are ordinary ones. A group that needs somewhere to talk for an afternoon without everybody joining a platform. A person on a device they do not control. Somebody who wants one conversation and not another account. A link you can paste into an email or turn into a QR code, where whoever opens it is simply in the room. That is the whole shape of it.
Does this work on a Chromebook?
Yes. It is a web page, so a Chromebook needs nothing extra and no permission from whoever manages the device, as long as the network itself allows the site.
Do I need to allow notifications or a microphone?
No. The site does not ask for notifications, a microphone, a camera or your location, because it does not use any of them. It is text only.
Will it work on an old browser?
Usually. It needs JavaScript and WebSocket support, which browsers have had for well over a decade. Very old or heavily stripped-down browsers may not manage the live connection.
Can my employer or school see that I used it?
Yes, in the same way they can see any site you visit on their network. The connection is encrypted, so the contents of what you type are not visible to them, but the domain you visited is. Nothing on this site changes what network monitoring can see.
Is there a desktop app if I want one?
No, and there are no plans for one. If you want it to feel like an app, most browsers will let you save a page to your home screen or desktop as a shortcut.