Abstract: There are provided systems and methods for checkout approval through feature flag tracking and guided user data flows. An online transaction processor may provide account establishment and/or know your customer (KYC) data verification at merchant checkout through use of different account processes and feature flags for mobile applications. A user may utilize their mobile device to scan a code at the merchant checkout, which may cause loading of an interface in the mobile application and a corresponding feature flag. Based on whether the user has previously used the application and/or has an account with the transaction processor, the user may be guided to a processing flow for data input, processing, and verification. The data may include KYC data, which may be used to perform a risk assessment of the user and determine a spending limit extendable to the user.