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Luke · Software Developer
Luke · Software Developer

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Why “99.9% uptime” doesn’t mean your users are fine

For years, uptime has been treated as the ultimate signal of reliability.

If a dashboard shows 99.9% uptime, everything must be fine.

Servers respond. Checks are green. Alerts are silent.

And yet, users complain.

Pages load but don’t render correctly.

Critical actions fail.

Performance is inconsistent depending on where users are located.

From a monitoring perspective, everything looks “up”.

From a user’s perspective, the product feels broken.

This disconnect is more common than most teams realize.


Uptime is an infrastructure metric

Uptime answers a very specific question:

Does a server respond to a request?

That’s it.

It doesn’t tell you:

  • whether the page actually renders
  • whether critical user flows work
  • whether the experience is usable
  • whether users in different regions see the same thing

Uptime is necessary, but it’s only a baseline.

Treating it as a proxy for user experience is where problems begin.


When everything is “up” but nothing works

Many real incidents don’t show up as downtime:

  • A frontend deploy introduces a JavaScript error
  • An API responds, but returns incorrect data
  • A checkout page loads but fails silently
  • A CSS issue breaks layout on specific devices
  • A feature flag misconfiguration affects only part of the audience

From the outside, the site is reachable.

From the inside, dashboards stay green.

From the user’s point of view, the product is unusable.


The regional blind spot

Another common failure mode is regional availability.

A site may be:

  • fully accessible from one country
  • slow or unreachable from another

CDNs, DNS resolution, routing paths, and ISPs all play a role here.

Centralized monitoring often checks from a limited set of locations.

If those locations are healthy, the issue stays invisible.

This is why teams hear:

“I can’t reproduce it.”

And users keep experiencing problems.


Why teams struggle to communicate incidents

When availability issues are unclear, communication breaks down too.

Teams fall back to:

  • replying to individual support tickets
  • posting updates in chat tools
  • sending ad-hoc emails
  • answering “is it down?” repeatedly

There’s no single source of truth.

Users don’t know where to look.

Support load increases exactly when teams are already under pressure.

The problem isn’t just technical.

It’s about shared understanding.


What actually helps

Teams that handle incidents well tend to focus on a few principles:

  • Think in terms of availability, not just uptime
  • Look at systems from the user’s perspective
  • Verify reachability from outside their own environment
  • Detect user-facing breakage, not just server response
  • Communicate clearly and consistently

Monitoring becomes less about collecting metrics

and more about reducing uncertainty.

If you want a deeper look at how uptime differs from real availability,

this guide explores the topic in more detail:

👉 https://perkydash.com/guides/why-uptime-is-not-enough


Quick checks still matter

Sometimes, teams don’t need a full dashboard or historical data.

They just need a fast answer to a simple question:

Is the site reachable for users right now?

A quick external check can help:

  • confirm or rule out availability issues
  • validate user reports
  • decide whether deeper investigation is needed

Tools that check reachability from the outside are useful exactly because

they step outside internal networks, cached DNS, and existing sessions.

Here’s a small free tool that does just that:

👉 https://perkydash.com/tools/uptime-check


Availability is the real goal

Uptime should be treated as a baseline, not a success metric.

What users care about is whether they can:

  • access the product
  • use it as expected
  • complete what they came to do

When teams shift their mindset from uptime to availability,

they start seeing issues earlier, communicating better,

and making decisions with more confidence.

Green dashboards are reassuring.

Understanding what users actually experience is far more valuable.

Top comments (1)

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lideroocom profile image
Luke · Software Developer

Thanks for reading 🙏

This article comes from real situations I’ve seen repeatedly:
green dashboards, no alerts, and users still reporting issues.

I’m curious how others here think about availability in practice:

  • Do you rely mostly on uptime metrics?
  • Have you experienced regional or user-facing issues that were hard to reproduce?
  • How do you usually verify what users are actually seeing during incidents?

Happy to discuss and learn from different approaches.