HTTP 100 Continue vs 431 Request Header Fields Too Large
HTTP 100 (Continue) is a 1xx Informational response, while 431 (Request Header Fields Too Large) is a 4xx Client Error response. 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. In contrast, 431 means that the server refuses to process the request because an individual header field or all headers collectively are too large.
説明
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.
このコードが表示される場合
When a client sends an Expect: 100-continue header, the server responds with 100 before the client sends the body.
解決方法
This is an interim response — no fix needed. The client should continue sending the request body.
説明
The server refuses to process the request because an individual header field or all headers collectively are too large.
このコードが表示される場合
When cookies accumulate to an excessive size, or a single header (like Authorization) is too long.
解決方法
Reduce header sizes. Clear excessive cookies. Use shorter tokens.
主な違い
100 is a 1xx Informational response, while 431 is a 4xx Client Error response.
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 431: The server refuses to process the request because an individual header field or all headers collectively are too large.
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 431 when when cookies accumulate to an excessive size, or a single header (like Authorization) is too long.
どちらをいつ使うか
For 100 (Continue): This is an interim response — no fix needed. The client should continue sending the request body. For 431 (Request Header Fields Too Large): Reduce header sizes. Clear excessive cookies. Use shorter tokens.