Have you ever clicked a link and seen a confusing error like “404 Not Found”?
Those numbers are HTTP status codes, and they’re the web’s way of telling you what happened with your request.
In this blog post, I’ll explain these codes in plain language, breaking them into bite-sized pieces so you can understand them easily.
What Are HTTP Status Codes Anyway?
HTTP stands for HyperText Transfer Protocol — it’s the system your browser uses to talk to websites.
The “status code” part is like a quick note the server sends back after you make a request, such as loading a page. Imagine it as a traffic light: green for go, red for stop, and yellow for “hold on.”
These codes are just three digits, but they pack a lot of info. They tell you if your request worked, if you need to try something else, or if the server’s having a bad day.
Simple, right?
The Five Groups of HTTP Status Codes
HTTP status codes come in five flavors, grouped by their first digit: 1xx, 2xx, 3xx, 4xx, and 5xx.
Each group has a unique role. Let’s break them down one by one so you can see how they fit into your web experience.
1xx: Info on the Way
Codes starting with 1 are rare visitors. They pop up when the server says, “I got your request, keep going.”
It’s like a waiter acknowledging your order before bringing the food.
Common Examples
- 100 Continue: You’re sending a big file, and the server says, “Looks good so far—finish uploading.”
- 101 Switching Protocols: You asked to change how you’re talking to the server (say, from regular web to a live chat), and it agrees.
- 103 Early Hints – Used for preloading resources before the final HTTP response.
You won’t see these often, but they help behind the scenes, especially with fancy tech like video calls.
2xx: Success—You’re Golden!
Codes in the 2xx club mean everything worked out. You asked for something, and the server delivered.
It’s a high-five from the web.
Common Examples
- 200 OK: You loaded a webpage perfectly—nothing to worry about here.
- 201 Created: You just uploaded a photo, and the server made a new spot for it.
- 202 Accepted: The request has been received but is being processed asynchronously
- 204 No Content: You deleted something, and the server says, “Done, but there’s nothing to show.”
- 206 Partial Content: The server has delivered only part of the requested content
These are the happy codes you want. They mean your browsing or uploading went off without a hitch.
3xx: Time to Redirect
The 3xx codes nudge you to go somewhere else. The server’s saying, “What you want isn’t here—try this spot instead.”
Common Examples
- 301 Moved Permanently: That old blog link you clicked? It’s got a new home forever, and your browser will remember it.
- 300 Multiple Choices – The client must choose from multiple response options.
- 302 Found: The page moved for now, but it might come back later.
- 303 See Other – The client should retrieve the resource using a GET request at a different URL.
- 304 Not Modified: You’ve seen this page before, and it hasn’t changed—use what’s saved on your device.
- 304 Not Modified – The requested resource has not changed since the last request (used for caching).
- 305 Use Proxy – The requested resource must be accessed through a proxy.
- 306 (Unused) – No longer in use.
- 307 Temporary Redirect – Similar to 302, but ensures the request method does not change.
- 308 Permanent Redirect – Similar to 301, but ensures the request method does not change.
Redirects keep you on track when websites shift things around. They’re super common and usually happen without you noticing.
4xx: Oops, That’s on You
When you see a 4xx code, it’s a sign you messed up somehow. Maybe you typed a bad link or forgot to log in.
The server’s pointing the finger back at you.
Common Examples
- 400 Bad Request: You sent something weird, like a broken form, and the server can’t figure it out.
- 401 Unauthorized: You need to log in—enter that password!
- 403 Forbidden: You’re not allowed in, even if you’ve got the right key.
- 404 Not Found: The page is gone—maybe it never existed.
- 405 Method Not Allowed: You tried a trick the server doesn’t like (tech folks call this an unsupported “HTTP method”).
Other 4XX Codes
✔ 402 Payment Required – Reserved for future use (sometimes used for paid API access).
✔ 406 Not Acceptable – The requested resource cannot generate a response acceptable to the client.
✔ 407 Proxy Authentication Required – The client must authenticate with a proxy server.
✔ 408 Request Timeout – The server timed out waiting for the request.
✔ 409 Conflict – The request could not be completed due to a conflict with the current resource state.
✔ 410 Gone – The resource was once available but is now permanently gone.
✔ 411 Length Required – The request must include a valid Content-Length header.
✔ 412 Precondition Failed – The server does not meet the preconditions specified by the client.
✔ 413 Payload Too Large – The request body is too large for the server to process.
✔ 414 URI Too Long – The requested URL is too long for the server to process.
✔ 415 Unsupported Media Type – The server does not support the media type in the request.
✔ 416 Range Not Satisfiable – The requested range is not available for the resource.
✔ 417 Expectation Failed – The server cannot meet the Expect request-header field requirements.
✔ 418 I’m a Teapot – A joke status code from the Hyper Text Coffee Pot Control Protocol.
✔ 421 Misdirected Request – The request was sent to a server that cannot produce a response.
✔ 422 Unprocessable Entity – The request is well-formed but cannot be processed.
✔ 423 Locked – The resource is locked.
✔ 424 Failed Dependency – The request failed because a previous request failed.
✔ 425 Too Early – The server is unwilling to process the request early to prevent replay attacks.
✔ 426 Upgrade Required – The client must upgrade to a different protocol.
✔ 428 Precondition Required – The server requires the request to have preconditions.
✔ 429 Too Many Requests – The client has sent too many requests in a given period (rate limiting).
✔ 431 Request Header Fields Too Large – The request headers are too large.
✔ 451 Unavailable For Legal Reasons – The resource is unavailable due to legal restrictions.
These errors help you fix what went wrong. A quick tweak, like correcting a URL, often does the trick.
5xx: Server’s Having a Meltdown
The 5xx codes mean the server’s in trouble — not your fault!
Common Examples
- 500 Internal Server Error: Something broke, and the server’s too embarrassed to explain.
- 502 Bad Gateway: The server asked another server for help and got nonsense back.
- 503 Service Unavailable: The site’s down—maybe too many people showed up at once.
- 504 Gateway Timeout: The server waited too long for an answer and gave up.
Other 5xx status codes
- 501 Not Implemented – The server does not support the request method.
- 502 Bad Gateway – The server received an invalid response from an upstream server.
- 505 HTTP Version Not Supported – The server does not support the HTTP version used in the request.
- 506 Variant Also Negotiates – A variant resource is configured incorrectly.
- 507 Insufficient Storage – The server cannot store the requested data.
- 508 Loop Detected – The server detected an infinite loop while processing a request.
- 510 Not Extended – Further extensions are required for the request to be fulfilled.
- 511 Network Authentication Required – The client must authenticate to gain network access.
You can’t fix these, but they let you know to try again later. Patience is your friend here.
Common HTTP Status Codes in Web Development
Here’s a handy table to pin up in your brain. Scan it whenever you hit a code and need a fast answer.
| Status Code | Meaning | Usage Example |
| 200 OK | Success | Standard response for successful requests |
| 301 Moved Permanently | Redirect | Used for permanent URL changes |
| 302 Found | Temporary Redirect | Used for temporarily moved resources |
| 400 Bad Request | Client Error | When a request is improperly formatted |
| 401 Unauthorized | Authentication Required | When login or API authentication is needed |
| 403 Forbidden | Access Denied | When the client doesn’t have permission |
| 404 Not Found | Resource Missing | Common for broken links or missing pages |
| 500 Internal Server Error | Server Failure | When an application or backend fails |
| 503 Service Unavailable | Server Overload | Used for maintenance mode or overloading |
Why Should You Care About HTTP Status Codes?
You might wonder, “Do I really need to know this?”
If you’re just browsing, maybe not—but it’s empowering. Spotting a 404 means you can double-check that URL yourself.
For anyone building a website or app, these codes are your best pals. They tell you if your visitors are happy or hitting roadblocks.
Even as a casual user, understanding them cuts the mystery out of errors. Next time you see “502 Bad Gateway,” you’ll know the server’s having a rough day—not you.
How to Handle HTTP Status Codes?
For SEO:
- 301 Redirects should be used for permanent URL changes to avoid broken links.
- 404 Pages should be customized to help users find alternatives.
For API Development:
- Use 429 Too Many Requests for rate-limiting users.
- Use 400 Bad Request when the client sends an invalid request.
For Web Performance:
- Cache responses with 304 Not Modified to reduce bandwidth usage.
- Avoid excessive 500 Errors by handling server-side errors properly.
Understanding HTTP status codes is crucial for debugging, optimizing performance, and improving user experience.
