Event schedule changes
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.
Draft, schedule, send — and what cancelling cannot undo
Composing and sending are deliberately different permissions, so the person or script that writes an alert can be forbidden from publishing it. A scheduled alert becomes visible at its time without anything having to run at that minute, which means a server that was briefly down delivers late rather than never. Cancelling is honest about its limits: it stops an alert reaching phones that have not fetched it yet and does nothing at all to the phones that already have it. An alert cannot be unsent.
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.
Four subscribers or four million, same message
Sending does not fan out into per-recipient work: an alert is written once and each phone asks for what it has not seen. That is why the cost and the speed do not change with the size of the audience, why there is no queue to drain and no per-message price to negotiate. It is also the reason the honest-numbers section reads the way it does — the same design that makes it cheap is what makes a delivery receipt impossible.
Questions, answered plainly
Can I unsend an alert?
No. Cancelling stops it reaching phones that have not fetched it yet, and does nothing to the ones that already have it. Compose as a draft and read it back before you send; that habit is worth more than any undo button we could offer.
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.
Does it get slower or more expensive as we grow?
No. An alert is written once and each device asks for what it has not seen, so four million subscribers cost the same to send to as four. Your plan caps how many subscribers a channel may have, but the send itself does not change shape.
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