HTTP 100 Continue vs 503 Service Unavailable
HTTP 100 (Continue) is a 1xx Informational response, while 503 (Service Unavailable) is a 5xx Server 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, 503 means that the server is temporarily unable to handle the request due to maintenance or overload. Should include a Retry-After header.
Описание
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.
Когда вы это видите
When a client sends an Expect: 100-continue header, the server responds with 100 before the client sends the body.
Как исправить
This is an interim response — no fix needed. The client should continue sending the request body.
Описание
The server is temporarily unable to handle the request due to maintenance or overload. Should include a Retry-After header.
Когда вы это видите
During maintenance windows, server overload, or when the application pool is exhausted.
Как исправить
Wait and retry. Check the Retry-After header. Scale up servers if it's a capacity issue.
Ключевые различия
100 is a 1xx Informational response, while 503 is a 5xx Server 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 503: The server is temporarily unable to handle the request due to maintenance or overload. Should include a Retry-After header.
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 503 when during maintenance windows, server overload, or when the application pool is exhausted.
Когда что использовать
For 100 (Continue): This is an interim response — no fix needed. The client should continue sending the request body. For 503 (Service Unavailable): Wait and retry. Check the Retry-After header. Scale up servers if it's a capacity issue.