---
name: "CURLOPT_UPKEEP_INTERVAL_MS"
section: "3"
platform: "linux"
package: "curl"
version: "8.23.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/CURLOPT_UPKEEP_INTERVAL_MS"
---

# CURLOPT\_UPKEEP\_INTERVAL\_MS(3)

connection upkeep interval

## NAME

CURLOPT\_UPKEEP\_INTERVAL\_MS - connection upkeep interval

## SYNOPSIS

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

## 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)](/curl_easy_upkeep/3.md)* 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)](/curl_easy_upkeep/3.md)* is called, an HTTP/2 PING frame is sent on the connection.

## DEFAULT

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

## PROTOCOLS

This functionality affects all supported protocols

## 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

Added in curl 7.62.0

## RETURN VALUE

*[curl\_easy\_setopt(3)](/curl_easy_setopt/3.md)* returns a CURLcode indicating success or error.

CURLE\_OK (0) means everything was OK, non-zero means an error occurred, see *[libcurl-errors(3)](/libcurl-errors/3.md)*.

## SEE ALSO

[**CURLOPT\_TCP\_KEEPALIVE**(3)](/CURLOPT_TCP_KEEPALIVE/3.md)