404 NOT FOUND!

The classic status code everyone has seen before. You click a link and get a big error staring back at you — but what does it actually mean? It means the server is up and running, it received your request just fine, but the specific page or resource you asked for doesn’t exist. It’s like walking into the right building but trying to go to a room that was never there.

There are 4 status code ranges that tell you what happened at a glance:

• 2xx — Success. Everything went as expected.
• 3xx — Redirect. The resource has moved somewhere else.
• 4xx — Client’s fault. You sent something wrong or don’t have permission.
• 5xx — Server’s fault. Something broke on the backend.

A 2xx means you’re good — like 200 OK for a successful request or 201 Created when something new gets added. But the 4xx range is where it gets interesting. If you try to access your bank account without being logged in, you’ll get a 401 Unauthorized — the server doesn’t know who you are. If you’re logged in but try to access someone else’s account, that’s a 403 Forbidden — the server knows exactly who you are, it just won’t let you in. Status codes tell you specifically what went wrong so you’re not left guessing.

Certain status codes are important to know if you are a software developer or just someone who likes to understand the little things.

• 200 — OK — This is the standard success response. Your browser requested the HTML from the server and everything came back fine.
• 201 — Created — You get this when something new is made, like creating a new user account. The server is saying “got it, here’s what was just created.”
• 204 — No Content — Success, but nothing to send back. This is common after a DELETE request — the thing is gone so there’s nothing to return.
• 301 — Moved Permanently — The page has a new home forever. Update your bookmarks and links because it’s not coming back to the old URL.
• 302 — Moved Temporarily — Like a site that redirects you to a maintenance page. Follow the redirect but keep the original URL saved because it’ll be back.
• 400 — Bad Request — The data you sent was wrong or missing something. The server couldn’t understand it.
• 401 — Unauthorized — You’re not logged in. Like trying to access your bank account without entering your password first.
• 403 — Forbidden — You’re logged in but you don’t have permission. Like trying to access someone else’s bank account.
• 404 — Not Found — The server is running fine but the page or resource you asked for doesn’t exist.
• 500 — Server Error — Something broke on the server side. Not your fault — the backend crashed or hit an unexpected bug.

These status codes give so much insight into what’s happening behind closed doors. So much is going on that we can’t see with the naked eye, and these codes are crucial for knowing whether everything went smoothly — or figuring out exactly what went wrong when it didn’t.