Determining time of last input post

I’m looking for a simpler way to determine the last time an input was posted, without knowing an eMonCMS ID for any of the inputs. I know the node number, and the “name” (JSON element that seems to correspond to the “KEY” field in the input list).

Requesting the whole input list is a problem because it is potentially very large, and I can’t guaranty enough memory (ESP8266) to parse it all with arduinoJSON. Is there a way to get information about a single input identified by “node” and “name”, or even to filter by a particular node?

Any other solution to the problem is welcome, as sometimes I miss the obvious. Short of that, I will need to write my own code to read the JSON from input/list.json. Rather not do that.

The reason I need the time is to roll forward from local SD storage after a failure to update (wifi was down, emoncms was down).