CURLOPT_MAX_SEND_SPEED_LARGE - rate limit data upload speed

Added in curl 7.15.5

0, disabled

Pass a curl_off_t as parameter with the maxspeed. If an upload exceeds this speed (counted in bytes per second) the transfer pauses to keep the average speed less than or equal to the parameter value. Defaults to unlimited speed. This is not an exact science. libcurl attempts to keep the average speed below the given threshold over a period time. If you set maxspeed to a value lower than CURLOPT_UPLOAD_BUFFERSIZE(3), libcurl might "shoot over" the limit on its first send and still send off a full buffer. This option does not affect transfer speeds done with FILE:// URLs.

int main(void) { CURL *curl = curl_easy_init(); if(curl) { CURLcode ret; curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/"); /* cap the upload speed to 1000 bytes/sec */ curl_easy_setopt(curl, CURLOPT_MAX_SEND_SPEED_LARGE, (curl_off_t)1000); /* (set some upload options as well) */ ret = curl_easy_perform(curl); } }

CURLOPT_MAX_SEND_SPEED_LARGE - rate limit data upload speed

This functionality affects all supported protocols

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).

CURLOPT_LOW_SPEED_LIMIT(3), CURLOPT_MAX_RECV_SPEED_LARGE(3) libcurl 2025-06-16 CURLOPT_MAX_SEND_SPEED_LARGE(3)

#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_MAX_SEND_SPEED_LARGE, curl_off_t maxspeed);