I think you can apply to get access to some sandbox from your bank (at least one of my EU banks does this) where you get access to documentation and fake APIs. Then you can go through a lengthy process to have it approved, but in my case I think it also requires a proper business entity to move it to "production". This might differ from bank to bank.

Or, you can use something like GoCardless which provides a sort of aggregated API and "connection APIs" for making things simpler: https://gocardless.com/bank-account-data/

Not affiliated with them, but I do use GoCardless to automatically import transaction data from a couple of EU bank accounts to my local datastore.

I wish. It's only available to licensed AISPs that carry fun requirements such as:

> The license can be obtained within 6-9 months for the application fee of 6,800 EUR. The minimum capital requirement varies depending on the nature and scale of the AISP’s activities but is typically around 125,000 EUR. The amount is ultimately determined on a case-by-case basis by the Dutch Central Bank which is the regulator of the Dutch financial market.

Not by regulation, you need a specific “payment service provider” licence for that.