Crystal — currently the most popular ad-blocker on the iOS App Store — is allowing advertisers who pay for the privilege to bypass the app's filters, a report said on Thursday.

The policy stems from a deal Crystal developer Dean Murphy forged with Adblock Pro creator Eyeo, the Wall Street Journal said. Eyeo does maintain an "acceptable ads" standard limiting intrusiveness, but over 70 companies, such as Google and Microsoft, have reportedly paid to skip past filters. Users can enable full ad blocking by disabling the "acceptable ads" option.

Over 700 businesses have ads that could potentially allowed through, Eyeo commented. The firm is paying Murphy a flat fee each month.

Murphy claimed to the Journal that he wants people to be able to support publishers, most of which are still dependent on ads for income.

"Given how popular Crystal has become, it doesn't provide any way for users to support publishers," he said. "I decided that's a good feature to provide, and from what I've seen the 'acceptable ads' policy doesn't let through what I'd classify as bad ads."

The app has already generated about $75,000 for Murphy, despite costing just 99 cents and having been out for a single week.