In July last year Journalism.co.uk reported on the Post's intention to develop a fact-checking tool after it was awarded a $50,000 grant from the Knight Foundation's Prototype Fund.
At the time, executive producer for digital news Cory Haik said the news outlet already had "a very robust fact-checking operation", but the idea was to add a "near real-time" element to its resources with Truth Teller.
Now the Post has launched the prototype of the application. Users can play a series of videos, with the speech also displayed as a transcript highlighted to show the part of the speech the video is playing.
Parts of the text are then compared to a database of facts, with the reader also able to click through to the specific sources of these facts. The prototype shows this fact-checking process in use with pre-recorded video relating to the tax reform debate.
But the plan is for Truth Teller to be used with live video and audio by the Post, behind-the-scenes, within a couple of weeks.
Haik said currently the application is "not totally there to just set it up and let it live stream". But she added that "the bones have been built".
In a press release the Post said the prototype of the app "is a step toward creating a Post app that can be used during live speeches and discussions".
"It currently focuses on the looming debate over tax reform. Users can play videos from President Barack Obama, Speaker of the House John Boehner and other politicians and instantly see which statements are true, false or misleading."
The release adds: "To create the prototype, the Post is using several technologies by combining video and audio extraction with a speech-to-text technology to search databases of facts and fact checks."
The Post has produced the below video to introduce the prototype: