DownDetector is the default answer when people search "is X down" — it has brand recognition and a large user base. But there is a fundamental limitation to how it works that affects the usefulness of what it tells you. Understanding the difference helps you pick the right tool when you need a fast, accurate answer.
What DownDetector actually measures
DownDetector aggregates user reports. When people visit the site and click "I have a problem," that vote is counted and graphed. A spike in reports is treated as evidence of an outage.
This is a useful signal — but it is only a signal. There are two key problems with relying on it alone.
First, crowd reports lag. Users experience a problem, search for it, find DownDetector, and submit a report. This process takes minutes. By the time a report spike appears, the outage has already been ongoing.
Second, crowd reports cannot distinguish between a global outage and a localised issue. If 2,000 users in one city lose access to a service because of an ISP routing problem, DownDetector will show a spike — even though the service itself is perfectly operational for everyone else.
What WebsiteDown adds
WebsiteDown runs a direct server-side HTTP probe to the target domain from our own infrastructure. This is not dependent on users submitting reports — it is an active check that happens the moment you enter a domain.
If our probe reaches the server and gets a valid response, the site is up — regardless of how many user reports exist. If our probe fails, the site is down from an external vantage point.
This distinction matters in two common scenarios. If a site has a vocal user base reporting problems but the server is actually reachable, the issues are likely client-side, regional, or account-specific — not a global outage. If a site has zero user reports but our probe is failing, you have early warning of an outage before the report volume catches up.
AI intelligence layer
On top of the server probe, WebsiteDown layers AI-powered web intelligence that scans social media, official status pages, and news sources in real time. This catches the nuanced outages that a binary probe misses: login systems failing, CDN edge nodes down in specific regions, payment processing errors.
The combination — live server check + community reports + AI signal scan — gives a more complete picture than any single signal source.
When to use which
Use DownDetector when you want to see historical outage patterns for a service — their graphs go back years and are useful for understanding how reliable a service has been over time.
Use WebsiteDown when you need an immediate answer right now: is this service actually reachable from the outside world, and what is the web saying about it in the last 15 minutes?
Both are free. The best answer often comes from checking both, but if you only have time for one, a server-side probe gives you something crowd reports cannot: an objective, real-time measurement that does not depend on how many users have already noticed the problem.