Associated Press offers a data feed http://ap.org/products-services/elections/FAQs https://developer.ap.org/ap-elections-api

"Shortly before the polls close, over 4,000 stringers report to county election centers. When the first polls close, they’ll be ready to start phoning in the raw vote as it is reported by the counties. They’ll place their calls to AP election centers around the country.

At the centers, a total of over 800 vote entry clerks will answer those calls, and walk each stringer through a dialogue as they enter the number of precincts reporting and the candidates’ votes into our election night system. "