Open Banking and open-source client-side software is a poor fit (btw, the "open" is a sham, there's nothing open about it).
Open Banking is implemented as a set of REST APIs using oAuth offered either by the banks directly (if you have the necessary regulatory approval) or by a gatekeeper such as TrueLayer/Plaid/etc (and I believe you can piggyback off their license, so no regulatory approval necessary).
Consuming oAuth APIs relies on guarding a client ID & the associated secret which would be impossible in an open-source app (or any client-side app for that matter, since extracting those is merely a reverse-engineering problem), therefore out-of-the-box Open Banking support is impossible.
However, nothing prevents them from developing the integration and let the end-user provide their own client ID/secret from their own accounts, and I believe most of these Open Banking providers have a free dev plan that can nevertheless connect to real accounts and would be enough for this.
In Germany, we have HBCI/FinTS, it's basically a standardised protocol to do "home-banking", and it works really well. I use an open source Java app, Hibiscus [0], and it connects to all my accounts and downloads the transactions. I can also make transfers in the software and they're pushed to the respective banks.
It's almost what I imagine client-server Open Banking could have been.
There's also the EBICS protocol, but that is more for B2B, server-server communication I believe.
Open Banking is implemented as a set of REST APIs using oAuth offered either by the banks directly (if you have the necessary regulatory approval) or by a gatekeeper such as TrueLayer/Plaid/etc (and I believe you can piggyback off their license, so no regulatory approval necessary).
Consuming oAuth APIs relies on guarding a client ID & the associated secret which would be impossible in an open-source app (or any client-side app for that matter, since extracting those is merely a reverse-engineering problem), therefore out-of-the-box Open Banking support is impossible.
However, nothing prevents them from developing the integration and let the end-user provide their own client ID/secret from their own accounts, and I believe most of these Open Banking providers have a free dev plan that can nevertheless connect to real accounts and would be enough for this.