HTTP 100 Continue vs 103 Early Hints
Both HTTP 100 (Continue) and 103 (Early Hints) belong to the 1xx Informational category. 100 indicates that the server has received the request headers and the client should proceed to send the request body. This lets the client know it can continue with the request or abort if the headers were rejected. Meanwhile, 103 means that used to return some response headers before the final HTTP message. Allows the browser to start preloading resources while the server prepares the response.
Description
The server has received the request headers and the client should proceed to send the request body. This lets the client know it can continue with the request or abort if the headers were rejected.
When You See It
When a client sends an Expect: 100-continue header, the server responds with 100 before the client sends the body.
How to Fix
This is an interim response — no fix needed. The client should continue sending the request body.
Description
Used to return some response headers before the final HTTP message. Allows the browser to start preloading resources while the server prepares the response.
When You See It
When a server wants the browser to start loading CSS/JS before the full response is ready.
How to Fix
No fix needed. This optimization helps speed up page loading.
Key Differences
HTTP 100: The server has received the request headers and the client should proceed to send the request body. This lets the client know it can continue with the request or abort if the headers were rejected.
HTTP 103: Used to return some response headers before the final HTTP message. Allows the browser to start preloading resources while the server prepares the response.
You encounter 100 when when a client sends an Expect: 100-continue header, the server responds with 100 before the client sends the body.
You encounter 103 when when a server wants the browser to start loading CSS/JS before the full response is ready.
When to Use Which
For 100 (Continue): This is an interim response — no fix needed. The client should continue sending the request body. For 103 (Early Hints): No fix needed. This optimization helps speed up page loading.