Is there a way to retrieve the OData API Metadata from all entities and also one specific entity?
To fetch the entire metadata of an instance, we use the API call: https://<hostname>/odata/v2/$metadata
However if you need to fetch the metadata of some specific entity, we can form the query as follows: https://<hostname>/odata/v2/User,Photo/$metadata
Above sample query would give you the metadata of only User and Photo entity. You just need to change the <hostname> by the url from your instance. Please check the article 2215682 to check on how to build your URL.
Odata API, Metadata, entity, $metadata, REST, WSDL, WADL , KBA , LOD-SF-INT-ODATA , OData API Framework , LOD-SF-INT , Integrations , How To