WordPress creator Matt Mullenweg has taken exception to the editor used in Wix’s mobile app, alleging that the do-it-yourself web building service has copied his platform’s editor and failed to give proper attribution and adhere to the general public license (GPL) — basically, to open source the work.

“If I were being honest, I’d say that Wix copied WordPress without attribution, credit, or following the license. The custom icons, the class names, even the bugs. You can see the forked repositories on GitHub complete with original commits from Alex and Maxime, two developers on Automattic’s mobile team,” he wrote in a blog post. “Wix has always borrowed liberally from WordPress — including their company name, which used to be Wixpress Ltd. — but this blatant rip-off and code theft is beyond anything I’ve seen before from a competitor.”

At the center of this controversy is the Wix app that was released earlier this month and allows Wix’s customers to manage their websites while on the go in real time. It comes with features such as the ability to have live chat, manage your ecommerce store, blog on the go, manage hotel bookings, and receive updates around your business operations. The company is in a similar space as WordPress, enabling users to quickly get a website up and running while keeping the content fresh — all without needing to hire a developer.

The issues may not be apparent without digging deeper into the code, but Mullenweg is bothered by the overall transaction. He says it’s not that he minds anyone borrowing the work for themselves, but that it’s important to abide by both the letter and the spirit of the GPL — essentially to pay it forward. It’s through this principle that WordPress’ creator says the platform has been able to flourish. WordPress now powers 25 percent of the web, including VentureBeat, which it has for more than a decade.

Mullenweg puts it this way: “If you want to close the door on innovation, Wix, that’s your decision to make — just write your own code. If you’re going to join the open source community, play by the open source rules.”

He said that Wix can make things right by open sourcing its app under the GPL and having the source code on GitHub so everyone can take advantage of the contributions.

We’ve reached out to Wix for comment and will update if we hear back.

Updated as of 2:07 p.m. Pacific on Saturday: Wix chief executive Avishai Abrahami has responded to Matt Mullenweg’s allegations, denying that his company stole code.