The app comes courtesy of Boston-based start-up Thumbs Up, which has been building audience engagement tools since last year, and built the app based on their existing API.

”This is our first use case for politics,” said founder Cass Sapir, who was previously a producer at WGBH’s NOVA. “We always knew that debates were one of the great use cases for this, so we pared down and simplified our feature set, and we were lucky to get this domain which really branded it for us.”

Getting started is as simple as pointing your desktop, tablet, or smartphone browser to RateTheDebate.org, selecting a party affiliation, and then clicking thumbs up or down as the debaters spar. Audience reaction is tracked in a constantly updating bar to the right, letting you get a feel for the pulse of the nation as you watch.

The site is also a good way for Thumbs Up to test out and showcase its technology: RateTheDebate is built using the site’s existing API, and the company plans to roll out additional features, such as tracking response by parties and location, for the third and fourth debates. Sapir said that the young startup, a graduate of the Betaspring accelerator, is in talks to roll out its services, including a native iPhone app, to help engage audience reactions across a wider variety of media, such as sports events.