New listing alerts for an estate agent
Setting this up takes about a minute. The slow part is not the software — it is deciding what to call yourself, because the handle ends up on a poster and cannot be changed afterwards.
What this actually looks like
The people most likely to buy are the ones who already asked you to call them. A channel is that list without the list: they subscribe, you post the new instruction with a photograph and a viewing time, and a circle on the map keeps it to the town it is actually in.
How you would set it up
- Create a channel for the branch and put its QR code in the window and on every particulars sheet.
- Post the listing with one good photograph attached and the first viewing slot in the text.
- Draw a geofence when a listing is genuinely local — the circle is compared on each phone, and no position is ever sent to us.
A picture, a sound or a document, when words are not enough
A diverted bus route is a map. A boil-water notice is a paragraph of instructions people will re-read. An alert can carry an image, a sound file or a document alongside the text. Documents are stored exactly as written and re-rendered from a sanitised copy rather than being run as markup, so an attachment cannot turn into a script on somebody’s lock screen. The bytes are uploaded once and attached by reference, which keeps a send cheap however large the audience.
One handle, printed once, permanent
A channel lives at drop.top followed by its handle, and that address never changes. It cannot be edited after creation, because it ends up on a poster in a school entrance, on a festival gate and inside a QR code somebody has already laminated. The page behind it explains what the channel is, what it asks a phone for, and how to subscribe — so a stranger reading a poster can decide before installing anything. We generate the QR code for you, server-side, and it is never sent to a third-party image service.
Draw a circle without knowing who is inside it
You place a centre and a radius on a map, and the circle travels attached to the alert. Every subscriber’s phone receives it and compares its own position locally, then decides whether to show it. No subscriber position is ever sent to us, which is why this is a design fact rather than a promise: there is no column anywhere that could hold one. Two consequences follow deliberately. A geofence only ever narrows — it cannot add somebody who did not subscribe. And it fails open: a phone that cannot work out where it is shows the alert rather than hiding it, because missing an evacuation is worse than seeing one meant for the next street.
Questions, answered plainly
Can I attach a map or a PDF?
You can attach an image, a sound file or a document. A document is stored exactly as submitted and rendered from a sanitised copy, so it can never execute anything on a subscriber’s phone.
Can I change my handle later?
No, and that is on purpose. It gets printed on posters and encoded into QR codes, and a handle that could change is a handle that turns somebody’s laminated sign into a dead link. Choose it the way you would choose a street name.
Do you know where my subscribers are?
No. The circle is sent with the alert and each phone compares its own position locally. We hold no subscriber location, so there is nothing to leak, subpoena or lose. A phone that cannot determine its position shows the alert rather than hiding it.
Do subscribers need an account?
No. They install the app, subscribe to a handle, and that is the whole of it. Only the person running the channel signs up for anything.
Say it once. Every subscribed phone gets it.
Free up to 100 subscribers, no card to start, and the handle is yours permanently.
Start a channel