Uptime is the share of time your website is reachable. Availability is the real-world version of the same question: can a visitor load your site right now, from where they are? They sound identical, and they're closely related — but the difference is where a lot of hosting decisions quietly get made.
Uptime measures whether the server is up. Availability measures whether a real visitor can actually reach your site. On a distributed network, the two stay close together — because there's no single machine whose failure takes the site offline.
What "uptime" really counts
Uptime is usually written as a percentage of time a service is up. You'll see figures like "three nines" or "four nines" — 99.9% or 99.99%. Those numbers are a useful shorthand, but they describe a single server's health, not your visitor's experience. A machine can be technically "up" while being too slow to use, or up in one city while unreachable from another. That's why it helps to think in terms of availability instead: not "is the server on?" but "can this person load the page?"
Why one server is a fragile way to stay online
If your entire site lives on one machine, that machine is the whole story. A power event, a network hiccup, a burst of traffic, a routine restart — any of them can take the site offline for everyone at once. You can make that one server sturdier, but you can't make it two places at once. There's a ceiling on how available a single point can be.
How a distributed network stays available
A global network changes the shape of the problem. Your site isn't tied to one server — it's served from many locations. If one location is busy or unreachable, the network simply routes visitors to the next nearest healthy one. Nobody gets a dead page while someone flips a switch; the reroute happens automatically, in the background. Watch it happen below: a visitor is being served by their nearest edge, that edge drops out, and traffic moves to the next nearest one without anyone lifting a finger.
Failover you never have to think about
The word for this is failover: healthy locations quietly pick up the work when another can't. On a single server, failover is something you engineer, monitor, and hope works when it's needed. On a network, it's the default behaviour — the same routing that sends each visitor to their nearest edge is what sends them to the next one if the first is out.
What actually affects your availability
- How many places serve your site. More independent locations means no single failure can take everything down.
- Whether rerouting is automatic. Availability depends on the network noticing a problem and moving traffic without you being involved.
- How your site is built. A static-first site has fewer moving parts that can fail than one that rebuilds every page on every request.
- Whether there's anything to maintain. Every server you have to patch or restart is another thing that can be down when you're not looking.
A note on uptime guarantees
Plenty of hosts advertise a specific uptime percentage. Treat those as a statement of intent rather than a promise your visitors will feel — a number on a page can't route around a failure by itself. What actually keeps a site available is the architecture underneath: many locations, automatic rerouting, and as little for a human to manage as possible. We'd rather point you at how the network behaves than quote you a figure and hope you never test it.
How this works on Just Web Hosting
Sites published with Just Publish are served across the whole network, so they're built to stay online by design. There's no single origin for you to watch, no failover to configure, and nothing to restart at 3 a.m. If a location has a bad moment, your visitors are already being answered somewhere else.
Hosting that is built to stay online.
Sites on Just Publish are served across the whole network — automatic failover, nothing to monitor or restart.