Is Cachly the Same as geocaching.com?
Cachly is an official partner app of geocaching.com and Geocaching HQ. Because of this, Cachly authenticates using the geocaching.com login page and connects to the Geocaching API. This allows data from the geocaching.com servers to be shown in Cachly.
From the Authorized Developer page:
Made possible through the support of Premium memberships, the API program gives third-party developers the opportunity to work with Geocaching HQ on a full suite of integrated products and services for the community. API partner applications are designed to work with the core services of Geocaching.com and provide additional features to the community and our Premium members.