CURLOPT\_UPKEEP\_INTERVAL\_MS(3) Library Functions Manual CURLOPT\_UPKEEP\_INTERVAL\_MS(3)

# [NAME](#NAME)

CURLOPT\_UPKEEP\_INTERVAL\_MS - connection upkeep interval

# [SYNOPSIS](#SYNOPSIS)

```
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_UPKEEP_INTERVAL_MS,


                          long upkeep_interval_ms);
```

# [DESCRIPTION](#DESCRIPTION)

Some protocols have "connection upkeep" mechanisms. These mechanisms usually send some traffic on existing connections in order to keep them alive; this can prevent connections from being closed due to overzealous firewalls, for example.

The user needs to explicitly call [*curl\_easy\_upkeep(3)*](/man/os/curl/curl_easy_upkeep.3) in order to perform the upkeep work.

Currently the only protocol with a connection upkeep mechanism is HTTP/2: when the connection upkeep interval is exceeded and [*curl\_easy\_upkeep(3)*](/man/os/curl/curl_easy_upkeep.3) is called, an HTTP/2 PING frame is sent on the connection.

# [DEFAULT](#DEFAULT)

CURL\_UPKEEP\_INTERVAL\_DEFAULT (currently defined as 60000L, which is 60 seconds)

# [PROTOCOLS](#PROTOCOLS)

This functionality affects all supported protocols

# [EXAMPLE](#EXAMPLE)

```
int main(void)
{


  CURL *curl = curl_easy_init();


  if(curl) {


    CURLcode result;


    /* Make a connection to an HTTP/2 server. */


    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");


    /* Set the interval to 30000ms / 30s */


    curl_easy_setopt(curl, CURLOPT_UPKEEP_INTERVAL_MS, 30000L);


    result = curl_easy_perform(curl);


    /* Perform more work here. */


    /* While the connection is being held open, curl_easy_upkeep() can be


       called. If curl_easy_upkeep() is called and the time since the last


       upkeep exceeds the interval, then an HTTP/2 PING is sent. */


    curl_easy_upkeep(curl);


    /* Perform more work here. */


    /* always cleanup */


    curl_easy_cleanup(curl);


  }
}
```

# [AVAILABILITY](#AVAILABILITY)

Added in curl 7.62.0

# [RETURN VALUE](#RETURN_VALUE)

[*curl\_easy\_setopt(3)*](/man/os/curl/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)*](/man/os/curl/libcurl-errors.3).

# [SEE ALSO](#SEE_ALSO)

[**CURLOPT\_TCP\_KEEPALIVE**(3)](/man/os/curl/CURLOPT_TCP_KEEPALIVE.3)

2026-09-24 libcurl

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Document: CURLOPT_UPKEEP_INTERVAL_MS(3) from curl 8.22.0-r3 (Chainguard OS)
Source: https://github.com/curl/curl.git