HTTP 425 Too Early vs 524 A Timeout Occurred
HTTP 425 (Too Early) is a 4xx Client Error response, while 524 (A Timeout Occurred) is a 5xx Server Error response. 425 indicates that the server is unwilling to risk processing a request that might be replayed. Used with TLS 1.3 early data (0-RTT). 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 is unwilling to risk processing a request that might be replayed. Used with TLS 1.3 early data (0-RTT).
When You See It
When a server rejects a request sent as TLS 1.3 early data due to replay risk.
How to Fix
Retry the request after the TLS handshake completes.
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
425 is a 4xx Client Error response, while 524 is a 5xx Server Error response.
HTTP 425: The server is unwilling to risk processing a request that might be replayed. Used with TLS 1.3 early data (0-RTT).
HTTP 524: Cloudflare-specific. A TCP connection was established but the origin didn't respond with an HTTP response in time.
You encounter 425 when when a server rejects a request sent as TLS 1.3 early data due to replay risk.
You encounter 524 when when a request to the origin takes longer than Cloudflare's 100-second timeout.
When to Use Which
For 425 (Too Early): Retry the request after the TLS handshake completes. For 524 (A Timeout Occurred): Optimize slow endpoints. Move long-running tasks to background jobs.