sschuberth/routex-client-kotlin

routex-client-kotlin is a toolkit that lets apps built with Kotlin connect to bank accounts through YAXI's Open Banking platform. Instead of an app developer having to build custom integrations for every individual bank, this library handles the communication so you can let your users link their accounts, search for banks, and fetch financial data. The library walks your app through the process of connecting to a bank step by step. First you search for a bank by name, then you ask the user for their credentials. From there, the library manages the back-and-forth conversation that banks require, things like asking the user to pick a login method, enter a TAN code, or visit a web page to confirm their identity. Once the user finishes these steps, the library hands your app the authenticated data and a token to speed up future requests. It also gives you a way to save the connection details, so your app can silently refresh that user's financial data later without making them log in again. This is built for developers creating personal finance apps, fintech products, or accounting tools who want to add bank connectivity. For example, if you are building a budgeting app and want to let a user securely pull their transaction history from their German bank, this library manages that entire flow. A companion "refresh client" is included for backend servers that need to automatically pull updated account balances in the background, long after the user originally gave their consent. The project is built using Kotlin Multiplatform, meaning it works natively on both standard Java server environments and Android apps. The code examples in the README use Kotlin's native asynchronous style, but Java developers can use a provided wrapper that works with standard Java futures. One important detail the README highlights is that when the library returns authenticated data as a signed token, your app should verify that signature in a trusted, secure environment before actually trusting or acting on the data.