1xx Informational Status Codes
Showing 4 status codes
HTTP 1xx status codes are provisional responses that indicate the server has received the client's request and is continuing to process it. These codes are sent before the final response and are used to communicate intermediate status information.
The most common 1xx codes include 100 Continue (used with the Expect: 100-continue header to check if the server will accept the request body), 101 Switching Protocols (used when upgrading to WebSocket or HTTP/2), and 103 Early Hints (used to preload resources while the server prepares the final response).
These informational responses help optimize communication between clients and servers, particularly for large uploads, protocol negotiations, and resource preloading. While browsers handle most 1xx responses automatically, understanding them is valuable for debugging and optimizing web applications.
1xx Informational Status Codes FAQ
What is the purpose of HTTP 1xx status codes?
HTTP 1xx status codes are informational responses that indicate the server has received the request headers and the client should continue with the request. They serve as interim responses before the final response is sent, helping with protocol negotiation, large uploads, and resource preloading.
Do I need to handle 1xx responses in my code?
Most HTTP clients and browsers handle 1xx responses automatically. However, if you're building a custom HTTP client or working with WebSocket connections (101 Switching Protocols), you may need to handle these responses explicitly.
What is the difference between 100 Continue and 102 Processing?
100 Continue indicates the server is ready to receive the request body (used with Expect: 100-continue header). 102 Processing indicates the server is still working on the request and prevents client timeout during long operations, commonly used in WebDAV.