c: Copyright (C) Daniel Stenberg, , et al. SPDX-License-Identifier: curl Long: hsts Arg: Protocols: HTTPS Help: Enable HSTS with this cache file Added: 7.74.0 Category: http Example: --hsts cache.txt $URL See-also: proto Multi: append --- This option enables HSTS for the transfer. If the file name points to an existing HSTS cache file, that will be used. After a completed transfer, the cache will be saved to the file name again if it has been modified. If curl is told to use HTTP:// for a transfer involving a host name that exists in the HSTS cache, it upgrades the transfer to use HTTPS. Each HSTS cache entry has an individual life time after which the upgrade is no longer performed. Specify a "" file name (zero length) to avoid loading/saving and make curl just handle HSTS in memory. If this option is used several times, curl will load contents from all the files but the last one will be used for saving.