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CURLOPT_ACCEPT_ENCODING(3)  Library Functions Manual  CURLOPT_ACCEPT_ENCODING(3)

NAME
     CURLOPT_ACCEPT_ENCODING - automatic decompression of HTTP downloads

SYNOPSIS
     #include <curl/curl.h>

     CURLcode curl_easy_setopt(CURL *handle, CURLOPT_ACCEPT_ENCODING, char *enc);

DESCRIPTION
     Pass a char pointer argument specifying what encoding you would like.

     Sets  the	contents of the Accept-Encoding: header sent in an HTTP request,
     and enables decoding of a response when a Content-Encoding: header  is  re-
     ceived.

     libcurl potentially supports several different compressed encodings depend-
     ing on what support that has been built-in.

     To  aid  applications  not  having to bother about what specific algorithms
     this particular libcurl build supports, libcurl allows a zero-length string
     to be set ("") to ask for an Accept-Encoding: header to be used  that  con-
     tains all built-in supported encodings.

     Alternatively,  you  can  specify exactly the encoding or list of encodings
     you want in the response. The following encodings are supported:  identity,
     meaning  non-compressed,  deflate which requests the server to compress its
     response using the zlib algorithm, gzip which requests the gzip  algorithm,
     (since  curl  7.57.0) br which is brotli and (since curl 7.72.0) zstd which
     is zstd. Provide them in the string as a comma-separated list  of	accepted
     encodings, like: "br, gzip, deflate".

     Set  CURLOPT_ACCEPT_ENCODING(3)  to  NULL	to  explicitly disable it, which
     makes libcurl not send an Accept-Encoding: header and  not  decompress  re-
     ceived contents automatically.

     You  can  also  opt  to include the Accept-Encoding: header in your request
     with CURLOPT_HTTPHEADER(3) but then there	is  no	automatic  decompressing
     when receiving data.

     Setting  this  option is a request, not an order; the server may or may not
     do it. It must be set (to any non-NULL value) or else any encoding done  by
     the server is ignored.

     Servers  might  respond  with  Content-Encoding: even without getting a Ac-
     cept-Encoding: in the request. Servers might respond with a different  con-
     tent encoding than what was asked for in the request.

     The  Content-Length: header field servers send for a compressed response is
     supposed to indicate the length of the compressed content so when auto  de-
     coding  is  enabled it may not match the sum of bytes reported by the write
     callbacks (although, sending the length of the non-compressed content is  a
     common server mistake).

     The  application does not have to keep the string around after setting this
     option.

     Using this option multiple times makes the last  set  string  override  the
     previous ones.

     WARNING: when decompressing data, even tiny transfers might be expanded and
     generate  a huge amount of bytes. You might want to limit using this option
     to only known and trusted sites using secure protocols, perhaps in combina-
     tion with CURLOPT_MAXFILESIZE_LARGE(3).

HISTORY
     This option was called CURLOPT_ENCODING before 7.21.6

NOTES
     The specific libcurl you are using must have been built  with  zlib  to  be
     able  to  decompress gzip and deflate responses, with the brotli library to
     decompress brotli responses and with the zstd library  to	decompress  zstd
     responses.

DEFAULT
     NULL

PROTOCOLS
     This functionality affects http only

EXAMPLE
     int main(void)
     {
       CURL *curl = curl_easy_init();
       if(curl) {
	 CURLcode result;
	 curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

	 /* enable all supported built-in compressions */
	 curl_easy_setopt(curl, CURLOPT_ACCEPT_ENCODING, "");

	 /* Perform the request */
	 result = curl_easy_perform(curl);
	 curl_easy_cleanup(curl);
       }
     }

AVAILABILITY
     Added in curl 7.21.6

RETURN VALUE
     curl_easy_setopt(3) returns a CURLcode indicating success or error.

     CURLE_OK (0) means everything was OK, non-zero means an error occurred, see
     libcurl-errors(3).

SEE ALSO
     CURLOPT_HTTPHEADER(3),   CURLOPT_HTTP_CONTENT_DECODING(3),   CURLOPT_TRANS-
     FER_ENCODING(3)

libcurl 			   2026-06-11	      CURLOPT_ACCEPT_ENCODING(3)

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