HTTP Status Codes Explained

Understanding HTTP Status Codes

For Atlanta readers, no, not that one. This sorta made-up but dev-approved holiday is dedicated to the most infamous of all HTTP status codes: 404 Page Not Found.

Status codes are the little three-digit messages your browser gets every time it tries to load something online. They’re how websites quietly tell you (or your dev team), “Hey, this worked,” or “Nope, something broke” and everything in between.

And while 404 is the one most folks know by name, it’s just one member of a whole family of codes—from 1XX to 5XX—all doing important behind-the-scenes work.

In honor of 404 Day, we’re breaking down what each group means—and translating some of the most common codes into plain English.

1xx: Informational Codes

These are the polite head nods of the HTTP world. They're rare, and you’ll probably never see them in the wild unless you're debugging something very specific.

• 100 Continue – “Cool, keep going.”
• 101 Switching Protocols – “Hang on, changing the way we talk.”
• 103 Early Hints – “Here’s what’s coming—don’t get too excited yet.”

2xx: Success Codes

These are the happy path responses. 200 codes mean everything’s working as expected—move along, nothing to fix here. Be more like a 200 success code.

• 200 OK – “All good, here’s your content.”
• 201 Created – “We made a new thing, just for you.”
• 204 No Content – “Mission accomplished, but there’s nothing to show.”

3xx: Redirection Codes

These codes are the detour signs of the internet. The page or file is somewhere else now—just follow the signs. If you’re familiar with 404s, then you may be familiar with 3XX codes that can fix them.

• 301 Moved Permanently – “That lives somewhere else now. Update your bookmarks.”
• 302 Found – “Temporarily hanging out over here.”
• 304 Not Modified – “No need to reload, you already have the latest version.”

4xx: Client Error Codes

These ones sometimes involve some finger pointing... 400-level codes pop up when something’s wrong with the request your browser made. Maybe a site editor deleted or moved a page to a draft without setting up a redirect? Maybe an old page never made the great migration from an older site? Either way. Nothing doing.

• 400 Bad Request – “That was nonsense. Try again.”
• 401 Unauthorized – “Who are you, and why don’t you have the password?”
• 403 Forbidden – “We know who you are. You still can’t come in.”
• 404 Not Found – “This page ghosted you.”
• 408 Request Timeout – “You took too long. The server got bored and moved on.”
  • P.S. This one’s commonly flagged by SEO scanning tools on login-gated content, like when you include external links to Facebook or LinkedIn on your site
• 418 I’m a Teapot – “I’m a teapot. I don’t brew coffee.” 
  • (Yes, this is real.)

5xx: Server Error Codes

These errors mean the server messed up. It heard your request, but something broke on its end. Nothing you can do but wait or call your friendly neighborhood dev.

• 500 Internal Server Error – “Something’s broken and it’s probably our fault.”
• 502 Bad Gateway – “The middleman server got a weird response.”
• 503 Service Unavailable – “The server’s taking a nap. Try again later.”
• 504 Gateway Timeout – “Too slow. We gave up waiting.”

Why Should I Care About HTTP Codes?

Even if you're not coding, these little numbers matter. A properly configured 301 redirect is a reliable weapon for a healthy SEO operation. Catching a bunch of 404s could mean fixing broken links before users bounce. And a spike in 500 errors? That’s your sign to call in backup.

We sweat the small stuff and QA tirelessly—like making sure your launch doesn’t ship with surprise 404s or mystery 500s. Plus, we love any opportunity to make 404 pages a little delightful (because if you're gonna land on an error, it might as well be cute).

Happy 404 Day, y'all. 🫖