Screenshot by Dara Kerr/CNET

A company that lets developers pull Craigslist data off the site is suing the online classifieds site for trying to stop competition in the growing market.

3Taps, which lets apps like PadMapper use Craigslist's listings, filed a counter lawsuit against Craigslist today, according to a court document (posted below). Craigslist originally filed suit against PadMapper and 3Taps for copyright infringement.

Not only does 3Taps's response deny Craigslist claims -- the company argues that public facts are public property and should be open for everyone to use -- it says Craigslist has created a "monopoly."

"While we respect what Craigslist has accomplished in the past in attaining dominance over online classified advertising, we object to them using that market power illegally to stifle innovation and hurt consumers," Greg Kidd, founder and CEO of 3Taps, said in an e-mailed statement. "As Craigslist spends heavily to bully and intimidate companies that challenge them, consumers are deprived of better ways to find and execute real-time exchange transactions."

We've asked Craigslist for a comment and will update when we hear back.

The online classifieds site warned apartment listings app PadMapper in June with a cease-and-desist letter. Craigslist claimed PadMapper -- which displays and links listings, found on Craigslist and other services, on a Google map -- was violating Craiglists' terms of use. PadMapper took the listings down, but then found a workaround provided by 3Taps. Craigslist filed suit shortly after.