---
title: early_hints
summary: null
url: >-
  https://www.fastly.com/documentation/reference/vcl/functions/tls-and-http/early-hints
---

```
VOID early_hints(STRING resource, STRING resource...)
```

**Available in:** recv, hash, hit, miss, pass, fetch, deliver, error

Emit an HTTP [103 early hint](https://tools.ietf.org/html/rfc8297)
informational response to help the client start making preparations for
processing the final response.

`early_hints` takes as a parameter headers in a text format. This function is
only effective for clients connecting using HTTP/2 or later.

Although the `early_hints` function can be invoked from any VCL subroutine,
invoking it in methods later than [hit/miss/pass](https://www.fastly.com/documentation/guides/vcl/using#the-vcl-request-lifecycle)
may not provide the benefits of the informational response. For example, if you
call `early_hints` in `vcl_deliver` the browser will receive the early hints
response at the same time as the main response headers.

## Example

```vcl
sub vcl_recv {
  if (fastly_info.is_h2 || fastly_info.is_h3) {
    early_hints("link: </hinted.js>; rel=preload", "link: </hinted.css>; rel=preload");
  }
}
```