• Get ConnectionStrings

ARMClient.exe post /{subscription}/resourceGroups/{resourceGroup}/providers/Microsoft.Web/sites/{site}/config/connectionStrings/list?api-version=2014-11-01 

Note: it is a POST since the result contains sensitive site info (only Owner and Contributor allowed).

• Update ConnectionStrings

ARMClient.exe put /{subscription}/resourceGroups/{resourceGroup}/providers/Microsoft.Web/sites/{site}/config/connectionStrings?api-version=2014-11-01 @payload.json 

Example payload.json below to add DUMMY ConnectionStrings.

{ "location": "West US", "properties": { "DUMMY": { "Value": "SomeValue", "Type": 0 } } }

Note: The update will replace the existing connectionStrings entirely. Hence, roundtripping any existing values is required.