In this reference, you can find two APIs.

Apps Gateway API

It allows you to initialize backend flows of the apps from our FinTech App Store.

Customer Information API

It allows you to get data that has already been saved in Transactionlink by any of the apps from our FinTech App Store. In other words, this is the only API you need to connect to in order to get the data from all the apps we provide.

Authorization

Both APIs (Gateway and Customer Information) use the same token to authorize your requests.
You can get your token via Authorization endpoint.
To get API keys required for authorization please visit getting access page.