Signal Types
SignalWhen supports four types of signals, each designed for a specific monitoring use case.
Website Change
Monitor any public webpage for content changes. SignalWhen fetches the page, extracts the text content, and compares it to the previous check.
URL — The webpage to monitor.
CSS Selector (optional) — Narrow monitoring to a specific part of the page.
Available on all plans.
Uptime
Monitor the availability of any URL. SignalWhen sends an HTTP request and checks if the server responds with a success status code.
URL — The endpoint to check.
Expected Status (optional) — The HTTP status code to expect (default: 200).
Available on Starter plans and above.
RSS Feed
Watch RSS and Atom feeds for new items. SignalWhen parses the feed and alerts you when new entries appear.
Feed URL — The RSS or Atom feed URL.
Available on Pro plans and above.
JSON API
Monitor any JSON API endpoint. SignalWhen fetches the response, extracts values using a JSON path, and alerts you when they change.
URL — The API endpoint.
JSON Path — Dot-notation path to the value to track (e.g.,
data.price).Headers (optional) — Custom request headers for authentication.
Available on Pro plans and above.