POST

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The HTTP POST method sends data to the server. The type of the body of the request is indicated by the Content-Type header.

The difference between PUT and POST is that PUT is idempotent: calling it once or several times successively has the same effect (that is no side effect), where successive identical POST may have additional effects, like passing an order several times.

A POST request is typically sent via an HTML form and results in a change on the server. In this case, the content type is selected by putting the adequate string in the enctype attribute of the <form> element or the formenctype attribute of the <input> or <button> elements:

  • application/x-www-form-urlencoded: the keys and values are encoded in key-value tuples separated by '&', with a '=' between the key and the value. Non-alphanumeric characters in both keys and values are percent encoded: this is the reason why this type is not suitable to use with binary data (use multipart/form-data instead)
  • multipart/form-data: each value is sent as a block of data ("body part"), with a user agent-defined delimiter ("boundary") separating each part. The keys are given in the Content-Disposition header of each part.
  • text/plain

When the POST request is sent via a method other than an HTML form — like via an XMLHttpRequest — the body can take any type. As described in the HTTP 1.1 specification, POST is designed to allow a uniform method to cover the following functions:

  • Annotation of existing resources
  • Posting a message to a bulletin board, newsgroup, mailing list, or similar group of articles;
  • Adding a new user through a signup modal;
  • Providing a block of data, such as the result of submitting a form, to a data-handling process;
  • Extending a database through an append operation.
Request has body Yes
Successful response has body Yes
Safe No
Idempotent No
Cacheable Only if freshness information is included
Allowed in HTML forms Yes

Syntax

POST /test

Example

A simple form using the default application/x-www-form-urlencoded content type:

POST /test HTTP/1.1
Host: foo.example
Content-Type: application/x-www-form-urlencoded
Content-Length: 27

field1=value1&field2=value2

A form using the multipart/form-data content type:

POST /test HTTP/1.1 
Host: foo.example
Content-Type: multipart/form-data;boundary="boundary" 

--boundary 
Content-Disposition: form-data; name="field1" 

value1 
--boundary 
Content-Disposition: form-data; name="field2"; filename="example.txt" 

value2
--boundary--

Specifications

Specification Title
RFC 7231, section 4.3.3: POST Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content
RFC 2046, section 5.1.1: Common Syntax Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
POSTChrome Full support YesEdge Full support YesFirefox Full support YesIE Full support YesOpera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support YesFirefox Android Full support YesOpera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support Yes

Legend

Full support  
Full support

See also