HEAD request method
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
The HEAD HTTP method requests the metadata of a resource in the form of headers that the server would have sent if the GET method was used instead.
This method can be used in cases where a URL might produce a large download, for example, a HEAD request can read the Content-Length header to check the file size before downloading the file with a GET.
If the response to a HEAD request shows that a cached URL response is now outdated, the cached copy is invalidated even if no GET request was made.
Warning:
If a response to a HEAD request has a body, the response body must be ignored.
Any representation headers that describe the erroneous body are assumed to describe the response body that a GET request would have received.
| Request has body | No |
|---|---|
| Successful response has body | No |
| Safe | Yes |
| Idempotent | Yes |
| Cacheable | Yes |
| Allowed in HTML forms | No |
Syntax
HEAD <request-target>["?"<query>] HTTP/1.1
<request-target>-
Identifies the target resource of the request when combined with the information provided in the
Hostheader. This is an absolute path (e.g.,/path/to/file.html) in requests to an origin server, and an absolute URL in requests to proxies (e.g.,http://www.example.com/path/to/file.html). <query>Optional-
An optional query component preceded by a question-mark
?. Often used to carry identifying information in the form ofkey=valuepairs.
Examples
Successfully retrieving resource metadata
The following curl command creates a HEAD request for example.com:
curl --head example.com
This is the equivalent to a GET request, except the server shouldn't include a message body in the response.
It creates an HTTP request that looks like this:
HEAD / HTTP/1.1
Host: example.com
User-Agent: curl/8.6.0
Accept: */*
The server sends back a 200 OK response comprised only of headers.
The response is effectively metadata that describes the resource instead of the resource itself (some caching headers are omitted in this example for brevity):
HTTP/1.1 200 OK
Content-Type: text/html; charset=UTF-8
Date: Wed, 04 Sep 2024 10:33:11 GMT
Content-Length: 1234567
Specifications
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| HTTP Semantics # HEAD |
Browser compatibility
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Legend
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- Full support
- Full support