Ability to track external account balances using API

It would be really cool to be able for developers to display custom balances inside the app by using the API. For examples being able to post a balance to the API and have it displayed in the App. And also have the API callout to a custom webhook when someone views the balance to have it update, and even transactions and extra information for these balances. Monthly payments etc, would good to have this as custom metadata so developers can specify this information.

I think this would be really useful as people could integrate into various types of accounts without Monzo needing to implement all of them. For example people could display their Loans Balances, Credit Cards, Crypto Currencies and anything else they can think of.