pfSense

Dynv6.com (https://dynv6.com/) provides dynamic DNS for A and AAAA records free of charge. The API is documented here: https://dynv6.com/docs/apis

Until support is officially added to pfSense users can utilize the service with a custom DDNS type with the following settings:

To update an AAAA record add a custom type with these settings:

Update URL: https://ipv6.dynv6.com/api/update?hostname=yourhostname.dynv6.net&ipv6=auto&token=YourDynV6APIToken
Result match: addresses unchanged|addresses updated

To update an A record add a custom type and simply change the update url to to: ipv4.dynv6.com

Update URL: https://ipv4.dynv6.com/api/update?hostname=yourhostname.dynv6.net&ipv6=auto&token=YourDynV6APIToken
Result match: addresses unchanged|addresses updated