RESTCONF combines REST principles with YANG data models. You get the simplicity of HTTP with the structure of YANG.
YANG models define the data structure. RESTCONF exposes that structure via HTTP URLs. Each YANG container becomes a REST resource.
Example URL:
/restconf/data/ietf-interfaces:interfaces/interface=GigabitEthernet1
Operations map to HTTP: GET reads data, PUT/PATCH modifies data, POST creates data, DELETE removes data.
Compared to NETCONF: Easier to use from web tools and scripts, supports JSON, no SSH session management.