- Property Manager name: Early Hints
- Behavior version: The
v2024-10-21
rule format supports theearlyHints
behavior v1.0. - Rule format status: GA, stable
- Access: Read/Write
- Allowed in includes: Yes
Use Early Hints to send an HTTP 103 status code with preliminary HTTP headers at the client request stage, so that a browser can preload critical website resources or preconnect to a specific domain while waiting for the final response.
The 103 response occurs only when the Sec-Fetch-Mode
request header’s value is navigate
. Since this is a default setting that’s already a part of the behavior’s logic, you don’t need to set any additional match criteria. However, if you add this behavior to a rule where a [requestHeader](#) criteria matches a
Sec-Fetch-Modevalue other than
navigate`, you get a validation error.
See the Property Manager guide for more caveats, examples, and implementations using EdgeWorkers.
Option | Type | Description | Requires | |
---|---|---|---|---|
enabled | boolean | Enable the behavior so that browsers can use that waiting time to preload the resource URLs you specify or preconnect to static or image domains. | {"displayType":"boolean","tag":"input","type":"checkbox"} | |
resourceUrl | string (allows variables) | Enter the URL to a resource you want clients to receive as an early hint. Edge servers include each resource URL you provide in an instance of the Example: | {"displayType":"string","tag":"input","type":"text"} {"if":{"attribute":"enabled","op":"eq","value":true}} |