Unit 1 · How the web works
404 vs 500 errors: who needs to fix it
A 404 means the server is fine but nothing lives at that address. A 500 means the page exists but the server failed while building it. Codes in the 4xx range point at the request; 5xx codes point at the server.
The mix-up
What people often think
“Every error is a 404.”
What the tutor says
404 means the address points at nothing. When the page exists but the server breaks building it, that is a 500.
How it works
Read the first digit. 2xx is success, 3xx sends you somewhere else, 4xx means the request asked for something wrong or missing, and 5xx means the server itself failed.
A wrong address never breaks a server; it gets a 404. A 500 is never the visitor’s fault and the visitor cannot fix it: the site’s team has to look at the server. If every visitor suddenly sees a 500, that is a server problem, not everyone typing the address wrong.
An example
200 OK the page, as asked
301 Moved Permanently it lives at a new address now
404 Not Found nothing at this address
500 Internal Server Error the server broke building itClose cousins of this mix-up
The tutor watches for these in the same lesson.
“A 500 means the page is gone.”
A missing page is a 404. A 500 means the page exists but the server failed while building it.
“A wrong address means the server is broken.”
The server is fine; it looked and found nothing at that address. That is a 404, not a 500.
“If a page fails, the visitor did something wrong.”
A 5xx code means the server failed. The visitor cannot fix it; the site's team has to.
Practise it with a tutor watching
Status codes
Read a status code and say who needs to fix the problem.
Free with an account. The first two units need no account.