Is it possible to search for people by precinct? I'd like to use the API to find all people in a given precinct, so that I can build a strikethrough system for election day.
You can not search for people by precinct. This is because the precinct is not a unique identifier for a person.
See what is possible with the precinct API here.
See which attributes are searchable here under "Search Endpoint".
Complete and current information on how to use NationBuilder is available in the documentation section.