Webfrontend and apps GoToSocial generally works with all Mastodon API compatible mobile and desktop apps, but it only has a read-only web-interface itself. So to post something to your account you need to use an external app. We host such an web-app for easy use on https://phanpy.f-hub.org   It will ask for the address of your Mastodon instance, where you can use social.f-hub.org to log in.