Well, it's on now.

Yesterday, Spotify publicly filed a complaint against Apple to the European Commission over "unfair" App Store rules, which allegedly make it hard for Spotify to compete with Apple Music on equal ground.

Today, Apple responded by saying that Spotify wants "all the benefits of a free app without being free," and throwing a couple more jabs for good measure.

In a lengthy post on the company's website, Apple said that Spotify has used the App Store "for years to dramatically grow their business," but now it wants to keep the benefits of that ecosystem "without making any contributions to that marketplace."

Furthermore, Apple says, Spotify's claims that Apple locked them out of its services such as Siri, HomePod and Apple Watch are untrue. Apple says it reached out to Spotify about Siri and AirPlay 2 support "on several occasions," to which Spotify replied it's "working on it." As far as Apple Watch goes, Apple claims it reviewed and approved Spotify's Apple Watch app, which was submitted in Sept. 2018, "with the same process and speed with which we would any other app." The company also points out that Spotify's Watch app is currently the number one app in the Watch Music category.

Regarding Apple's 30% tax that it levies on paid apps, which is the crux of Spotify's complaint as Apple Music is not subject to it, Apple says Spotify left out a few key pieces of info in its complaint. First, the 30% revenue share that Apple gets is for the first year of annual subscription, after which it drops to 15%. Also, Apple claims that the majority of Spotify customers use their free, ad-supported product, and a significant number of Spotify customers come through mobile carrier partnerships. Ultimately, Apple claims, only a "tiny fraction" of Spotify's subscriptions pay the 30% Apple tax.

"Let’s be clear about what that means. Apple connects Spotify to our users. We provide the platform by which users download and update their app. We share critical software development tools to support Spotify’s app building. And we built a secure payment system — no small undertaking — which allows users to have faith in in-app transactions. Spotify is asking to keep all those benefits while also retaining 100 percent of the revenue," Apple says.

In the post, Apple also pointed out that Spotify is stingy when it comes to paying artists, even taking them to court over royalties.

We'll undoubtedly hear more from both companies -- and the European Commission -- about this dispute in the future.

In response to our query, Spotify had no further comment beyond pointing to their version of the timeline and the facts related to the case.