I wanted to display my bank account balance on my mirror to easily track my finances. Nothing was available so I set up a Plaid account and created a module that checks their API every 10 min.
It’s safe. You have to use your own Plaid account and your access token is stored in the config file, and I, as the developer can’t access any of your financial information.

Here’s the repo: https://github.com/louisondumont/mmm-bank

Devs: This is my first module using the template found on github, and I coded it in 2h, so bear with me on the design or code cleanliness. I actually welcome anyone who would want to improve this module. So much can be done.
For example:

• cleaning the code
• allowing other countries besides US (Plaid supports many countriess)
• allowing multiple access tokens for multiple accounts
• displaying transactions
• displaying 24H/30D balance increase/decrease