What do status codes HTTP 100, 101, 102, and 103 mean?

An HTTP status code such as HTTP 100 is a way for a server to communicate with your browser in a standardised manner. The most well-known status code is probably 404, which users often encounter when a URL has been misspelled or removed. HTTP 100 through 103 are less common and can therefore be harder to understand when they appear.  

In this article, we’ll explain the meaning behind status codes HTTP 100, HTTP 101, HTTP 102, and HTTP 103. 

What is a 1xx status code? 

A status code in the 100 range is an informational status code. It is sent to a client to confirm that a request has been received, understood by a server, and that more data is expected. Put simply, a 1xx status code is like an acknowledgment that communication has started.  

This is why 1xx codes are rarely noticed by web users: they are usually followed by additional data that may lead to other status codes, which in turn reveal more about what is happening between server and client. 

What does HTTP 100 mean? 

The HTTP 100 status code is sent from a server to a client after the initial request has been received. HTTP 100 means the server is ready to receive further communication. The purpose is to ensure that data sent to the server is not lost or rejected. This makes communication between server and client more efficient. 

If a server does not send HTTP 100 in response, it may instead return a 403 error to indicate that the request is not allowed. 

What does HTTP 101 mean? 

HTTP 101 is used in response to a request to switch communication protocols. It usually starts with a client request called Upgrade. This request can be sent over HTTP but ask to switch to the WebSocket protocol for further communication. The server then responds with 101 to confirm the protocol switch. After that, the communication proceeds using the new protocol that both server and client have agreed upon. 

Vad betyder HTTP 102?

HTTP 102 is a fairly uncommon status code, but when it does appear, it means the server will send a response—it just takes longer. The delay is generally due to the server still processing the request, so the client is asked to wait for a response.  

Modern web hosting services are so fast that this status code is rarely used anymore. Delays can of course occur due to server overload, but in such cases, other status codes are typically used, such as HTTP 503. 

What does HTTP 103 mean? 

HTTP 103, also called Early Hints, is an important status code that helps websites load faster. With a 103 status code, a server can send information about resources and domains the client will need to connect to in order to display a website. 

For example, say you visit a site that loads images and JavaScript from another domain. After the client sends a request to the site, the site’s server responds with an HTTP 103 containing a link to the domain where the images and JavaScript are hosted, allowing the client to establish a new connection in advance. 

HTTP 103 is thus a way to save time and reduce loading times for a website. It is particularly useful for sites with many resources spread across several domains. HTTP 103 is primarily used with HTTP/2 because it allows multiple parallel resources over the same connection. 

What’s the difference between 1xx and 2xx status codes? 

Codes in the 100 range, such as HTTP 100, are status codes that indicate communication between a server and client is in progress. Codes in the 200 range, on the other hand, confirm that communication was successful and completed. The most common code in the 200 range is 200 OK, which means the page has loaded successfully. The key difference is that 1xx indicates more data is on the way, while 2xx shows the process is complete. 

Do you need to care about HTTP 100 status codes? 

HTTP status codes in the 100 range rarely appear while browsing, but they play an important role in communication between server and browser. Codes 100 through 103 are used to signal that a request has been received, that a protocol switch is occurring, that the server is still processing a request, or to speed up page loading. 

As a website owner, you rarely need to act on these status codes, but understanding what they mean can help with troubleshooting and when discussing technical issues with a developer or your web host. HTTP 103 is also a status code that can contribute to faster and more user-friendly websites. 

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