I have tried out Plaid Connect and it worked really well for me. This was in beta when only a very limited selection of banks were supported, so I had to go get a Bank of America account just to use it.

Authentication was incredibly easy and they handled security questions very gracefully in my opinion. I was able to build a pretty good Simple Goals clone with a weekend's worth of work.

I haven't used their Plaid Auth product yet.

Charley from Plaid here! We now support over 18,000+ banks in the US and Canada for Connect (transaction data) with our longtail integration :) https://plaid.com/docs/#long-tail-institutions

Intuit also offer an API to gather financial data. https://developer.intuit.com/docs/0020_customeraccountdata/0...

+1 for plaid. It's awesome, I built something similar to OP about 6 months ago just using plaid and my existing bank account.