HTTP 100 Continue vs 524 A Timeout Occurred
HTTP 100 (Continue) is a 1xx Informational response, while 524 (A Timeout Occurred) 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, 524 means that cloudflare-specific. A TCP connection was established but the origin didn't respond with an HTTP response in time.
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
Cloudflare-specific. A TCP connection was established but the origin didn't respond with an HTTP response in time.
When You See It
When a request to the origin takes longer than Cloudflare's 100-second timeout.
How to Fix
Optimize slow endpoints. Move long-running tasks to background jobs.
Key Differences
100 is a 1xx Informational response, while 524 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 524: Cloudflare-specific. A TCP connection was established but the origin didn't respond with an HTTP response in time.
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 524 when when a request to the origin takes longer than Cloudflare's 100-second timeout.
When to Use Which
For 100 (Continue): This is an interim response — no fix needed. The client should continue sending the request body. For 524 (A Timeout Occurred): Optimize slow endpoints. Move long-running tasks to background jobs.