Earlier this year, Apple announced that it would comply with a new law in South Korea that required the company to allow third-party payment providers in its App Store apps. Starting today, developers can finally apply to use payment methods other than Apple's in their apps distributed on the South Korean App Store.
See also: Google and Apple are being asked to remove TikTok from their app stores

Background
In August 2021, South Korea’s regulator passed an antitrust law to force both Apple and Google to allow developers to use third-party payment methods in their apps distributed through the App Store and Google Play. As expected, Apple appealed the decision, but the company ended up agreeing to comply with the law.
See also: Apple: What kind of apps we banned from our App Store last year
However, the South Korean regulator was not satisfied with Apple's proposal, as the company would charge a 26% commission for transactions made outside the App Store's in-app purchase system.
Third-party payment providers in South Korea
Apple on Thursday provided more details about how it will allow developers to offer third-party payment providers in their apps distributed in South Korea.
Like what happened in the Netherlands, where Apple created a special entitlement for dating apps that offer alternative payment methods, developers who want to offer an alternative payment processing option in South Korea must use the StoreKit External Purchase Entitlement.
Developers can continue to use Apple’s in-app purchase system if they want, but apps with alternative payment methods will need to create a new version exclusively for the South Korean App Store. Apple also notes that some features like Ask to Buy and Family Sharing will not be available for these apps. The company also won’t be responsible for any subscription management or refunds.
See also: Apple announces new data deletion rule for the App Store

For every sale made using an alternative payment method, developers will have to pay a commission to Apple – however, there will be a 4% discount. Apps will have to make it clear that the user will be paying through an alternative system that is not supported by Apple.
There are currently four South Korean payment providers certified by Apple: KCP, Inicis, Toss, and NICE. If a developer wants to use a different payment provider, they must first be verified by Apple. Those who want to submit an app to the South Korean App Store with an alternative payment method must fill out a request form on the Apple Developer website.
Information source: 9to5mac.com
