Server
- Standard term
A server is a program, or the computer running it, that waits for requests from other programs, called “clients,” and answers them by sending data or doing work.
Requests and answers follow an agreed format, called a “protocol,” such as HTTP for web pages. Because the format is shared, one server can answer any client that uses it, whether a browser, a phone app, or a script someone wrote yesterday, as long as the client knows the server's address.
Where you’ll meet it
Midway through a long answer, your AI chat app stops and shows "Something went wrong. Please try again." Other websites load fine, and so does the app's own page.
What to do
Since other websites load, your device and connection are fine, and the likely trouble is the servers that write the answers. Copy your prompt so it isn't lost, search the app's name with "status" to find the provider's status page, and retry once that page shows no problem.
Easy to mix up
| Server | Client |
|---|---|
| On a machine in a data center that stays on | On your own device, as a browser or an app |
Check yourself
A setup guide tells you to "restart the server" after you change a setting in your app. What should you restart?
Go deeperClient and server are roles, and one program can play both
Your app's server answers browsers, then becomes a client itself when it asks a payment company's server to charge a card. Chains like that can cross several companies' systems before a single reply comes back.
Most servers today are virtual machines, software copies of a computer that share one physical machine with others, or containers, apps packaged with what they need to run. Serverless hosting still runs on servers. The provider starts your code when a request arrives and stops it afterward, so you never manage the machine.