Please consider integrating with Aurmur Lock Control Services
Please consider integrating with Aurmur Lock Control Services. They have a unique option of a "check out" button that guests can press when leaving notifying the property manager and cleaners they are out of the house. They are also very inexpensive and allow for messaging guests their codes. I used them when I was with Guesty and was very happy with them. I was sad to discover that Hostfully doesn't integrate with them. It offers an affordable lock service that is reliable. Hosts need all the help they can get financially. We are using Jervis now but there is no comparison.
https://aurmur.com/api-documentation/
Please contact those providers and ask them to create an integration to Hostfully, as those particular integrations are typically implemented by the providers. Some integrators like Lynx might also provide an integration with this provider.