Know the second an endpoint breaks.
WhisperSentinel watches your HTTP endpoints and fires a native desktop alert the moment a condition you define is met. No dashboard to babysit, no data leaving your machine.
Features
Everything you need to catch a problem early.
Native desktop alerts
A real macOS, Windows, or Linux notification the moment a condition trips. No browser tab to keep open.
Checks on your schedule
Poll every ten seconds or every few hours. You set the interval per endpoint.
Conditions in JavaScript
Write a plain expression against the JSON response. Full access to the payload, no query language to learn.
A full history
Every trigger logged with timestamp and response body, so you can see exactly what happened and when.
Authenticated endpoints
Add Authorization headers or API keys to watch endpoints that sit behind a login.
Fire-once alerts
Tell an alert to stop after the first trigger, ideal for a price drop or a deal you only need to catch once.
Setup
Running in four steps.
Point it at an endpoint
Paste the URL you want to watch and, if it needs one, add a custom header.
Describe what's wrong
Write a JavaScript expression that reads the response. Reference the payload as "data".
Pick a frequency
Choose how often WhisperSentinel checks, from seconds to hours.
Get out of the way
It runs quietly in the background and only speaks up when your condition is met.
Use cases
If it returns JSON, you can watch it.
API monitoring
Watch production APIs and hear about it the second a service goes down or slows.
Business metrics
Track sales, signups, or inventory and get pinged when a number crosses a line that matters.
Price tracking
Follow a product price and catch the drop, then let the alert switch itself off.
System health
Keep an eye on error rates and server metrics so you catch trouble before your users do.
System requirements
macOS
- · macOS 10.15 or later
- · Intel or Apple Silicon
- · 50MB free disk space
Windows
- · Windows 10/11 (64-bit)
- · 50MB free disk space
- · Internet connection
Linux
- · Ubuntu 18.04+ or equivalent
- · X11 or Wayland
- · 50MB free disk space
Common questions
What can I point it at?
Any HTTP endpoint that returns JSON. REST APIs, webhook URLs, status pages, or anything custom you build.
Where does my data go?
Nowhere. Everything stays on your machine. WhisperSentinel doesn't collect, store, or transmit your endpoints or configurations.
How many endpoints can I watch?
As many as you want. Each alert has its own condition and interval.
Does it handle authenticated APIs?
Yes. Add Authorization tokens, API keys, or any headers your endpoint requires.
Need a hand?
Stuck on a condition or wondering if your endpoint will work? Ask us. A real person reads every message.