What are the most common HTTP status codes and their meanings?

1xx - Informational: 100 Continue 2xx - Success: 200 OK, 201 Created, 204 No Content 3xx - Redirection: 301 Moved Permanently, 302 Found, 304 Not Modified, 307 Temporary Redirect 4xx - Client Errors: 400 Bad Request, 401 Unauthorized, 403 Forbidden, 404 Not Found 5xx - Server Errors: 500 Internal Server Error, 501 Not Implemented, 503 Service Unavailable These codes provide information about the status of the request and help both clients and developers understand what happened during the communication between the client and the server.

HTTP status codes are three-digit numbers returned by web servers to indicate the status of a client's request. They are part of the HTTP/1.1 standard and include informational responses, successful responses, redirections, client errors, and server errors. Common status codes include "100 Continue," "101 Switching Protocols," "200 OK," "201 Created," "204 No Content," "206 Partial Content," "300 Multiple Choices," "301 Moved Permanently," "302 Found (or Moved Temporarily)," and "304 Not Modified." Understanding these codes can help diagnose and troubleshoot issues when interacting with web servers.

1. 1xx Informational: 100 Continue 1. 2xx Success: ? 200 OK ? 201 Created ? 204 No Content 2. 3xx Redirection: ? 301 Moved Permanently ? 302 Found ? 304 Not Modified 3. 4xx Client Errors: 400 Bad Request 401 Unauthorized 403 Forbidden 404 Not Found 4. 5xx Server Errors: 500 Internal Server Error 502 Bad Gateway 503 Service Unavailable 504 Gateway Timeout These are some of the most common HTTP status codes, but there are many more in the HTTP specification. Each status code carries specific meaning and provides information about the outcome of the request. Clients and servers use these status codes to communicate and handle different scenarios when exchanging HTTP requests and responses.

Using 1xx codes follows the general principle of HTTP that servers should provide helpful information to clients in the status code, headers, and body. The 1xx codes help avoid the client making incorrect assumptions if the final response is delayed. For example, 100 Continue indicates the initial request was valid and the client should continue sending the request body. They allow some optimization and efficiency improvements. For example, 103 Early Hints allows the server to send back key headers before the full response is ready. The 1xx codes tend to be uncommon in practice compared to 2xx success, 3xx redirects, etc. Servers don't usually need to provide a lot of interim information before the final response.

HTTP status codes are three-digit numbers that provide information about the status of a request made by a client to a server.. Here are some of the most common HTTP status codes and their meanings: 1xx Informational: 100 Continue 2xx Success: 200 OK 201 Created 204 No Content 3xx Redirection: 301 Moved Permanently 302 Found 304 Not Modified 4xx Client Error: 400 Bad Request 401 Unauthorized 403 Forbidden 404 Not Found 5xx Server Error: 500 Internal Server Error 501 Not Implemented 503 Service Unavailable These are some of the most commonly encountered HTTP status codes. There are additional status codes for more specific situations, and the complete list can be found in the HTTP/1.1 specification.

It's worth noting that there are different types of 3xx redirects ranging from permanent redirect to temporary redirect to not modified. This allows the server to signal the appropriate redirect handling to clients. 3xx codes are very commonly used in practice compared to other categories like 1xx informational. URL changes and caching are common needs, so redirects are essential for functional websites. One additional point is that incorrect or convoluted redirection paths using 3xx can sometimes cause problems for web crawlers. So it's best to implement clean and purposeful redirects.

Unlike 4xx errors which are common, 5xx errors indicate more serious issues and should happen infrequently for robust server applications. One extra point is that APIs should handle 5xx gracefully and implement fallback/retry logic, rather than just failing requests. The errors can be transient.