Zerowhen

Tell me when. Waiting is free.

Zerowhen runs small watchers that wait for something to happen and tell you when it does: a price drops, an appointment opens up, a certificate nears expiry. Set one up yourself, or ask your AI assistant to.

Between checks a watcher sleeps and costs nothing, so it can wait for weeks and still act the moment something happens.

For developers

Scale to zero, for real. A watcher is a shell script (curl, jq, grep and friends) in a sandbox. While it waits for a timer, a reply or a webhook, it parks: no process, no thread, no socket, about 100 KiB of storage. Then it resumes where it left off. Deploy one by command line, HTTPS API or MCP.

Our promise

We charge you; we don't study you.

• No ads, no data sales, no training on anyone's data.
• The least data: a watcher sees only its URL, selector, condition and fetched pages. An AI check sees only what changed, and its model gets no tools.
• Delete your account: its data is gone in 24 hours, from backups in 30 days.

In private testingQuestions or early access: hello@zerowhen.com