---
title: Check success now says what it actually measures
description: A monitor could sit at Down with check success reading 100%, which looks like a contradiction until you know what the number counts. It is a reachability…
canonical: https://watchfor.io/changelog/2026-09-06-check-success-meaning
---

[All updates](/changelog/page/4#2026-09-06-check-success-meaning) ⚡ Improved Sep 6, 2026 · v 6.8.1

# Check success now says what it actually measures

A monitor could sit at Down with check success reading 100%, which looks like a contradiction until you know what the number counts. It is a reachability figure: the share of checks where our probe reached your service and got a response. A response that then fails one of your rules — the wrong status code, a failed assertion, an expired certificate — still counts as reached, and shows up as an incident instead. The dashboard, reports, the docs and the API now all say this plainly: read check success for flakiness (timeouts, refused connections, one location misbehaving) and uptime for health.

## Two numbers, two questions

- Uptime answers "was the service healthy?" It goes down only for confirmed critical incidents.

- Check success answers "could we reach it?" It is the share of checks where our probe connected and got a response.

A response that fails one of your rules still counts as reached: an HTTP 500, a failed API assertion, an expired certificate. Those show up as incidents, and in uptime, instead.

## Example

At 14:00 your API starts answering every request with HTTP 503. Every check reaches it and gets an answer, so check success stays at 100 %. The status code rule fails, an incident opens, the monitor is Down and uptime drops.

A week later one location starts timing out every few checks while the others are fine. No incident opens and uptime stays at 100 %, but check success for that location drops. That is your hint to look at the network path from there, not at your code.

## Where you see it

Next to uptime in reports, per monitor and per location, and as check_success_percent in the API. A monitor with no checks in a period shows "—" rather than an invented 100 %. More in [How uptime is calculated](/docs/monitors#how-uptime-is-calculated).

Share this update

---

Canonical page: https://watchfor.io/changelog/2026-09-06-check-success-meaning · Site guide: https://watchfor.io/llms.txt