Apollo founder Christian Selig said he's "heartbroken" about pulling the plug on the third-party app following Reddit's API pricing changes.

A popular third-party Reddit app shut down Friday – and some of the social network's users are pledging to walk away as a result.

Some "Redditors" said in posts on Apollo's subreddit that they'll abandon the network.

"I'm gonna be dropping it," one user wrote. "I just finished using power delete suite to purge my entire history over the past 8 years."

Apollo founder Christian Selig said he would close down the app on June 30 after the company announced a pricing policy to charge developers an "egregiously high" price to access its API.

Third-party apps do not display the advertisements that generate revenue for Reddit – a problem for a company eyeing a stock market listing.

The app, which let Redditors access the platform through its own interface, had more than 1.5 million monthly users in June, Selig said, citing data from analytics firm Mixpanel.

"I suppose I feel a lot of emotions," Selig told Insider on Friday. "I'm heartbroken that an app I loved building and so many people enjoyed using over the years has come to an end so abruptly. And I'm genuinely surprised by how callous and dishonest Reddit has been toward developers, moderators, and the community as a whole over the last few weeks."

He said he felt "incredibly fortunate" to have built and worked with an "amazing community" who helped shape the app: "It's been the journey and honor of a lifetime, and I wouldn't have changed a thing."

The Canadian developer previously said Reddit's demands for compensation were unreasonable compared with how much money Apollo made from paid subscriptions.

"I'm going to quit mobile Reddit," said one user. "If it's not Christian who brings me news, memes and (let's be honest) porn, then I don't want it."

Another said it's "goodbye Reddit, not just goodbye Apollo. Switched to Apollo once Alien Blue went away. Have tried Reddit's official app; unusable is an understatement. Instead of getting used to a new app, I've been practicing getting used to no Reddit. End of an era."

Opponents of Reddit's changes have argued the company was built on the free labor of independent developers, and they should not be required to support Reddit financially.

Major communities on Reddit opted to go dark to protest the API changes, significantly reducing the amount of content on the service. Certain communities have labeled themselves as mature, therefore making themselves ineligible for advertising, to reduce Reddit's revenues.

Reddit did not immediately respond to a request for comment from Insider, made outside normal working hours.