Have you looked at Alpaca's Market Data API or Polygon.io. Both premium options are reasonably priced and give you access to both historical and real time trades. Source: over 1 year ago

I think https://alpaca.markets/data still offers free api keys for research purposes. Source: over 1 year ago

Https://alpaca.markets/data - As you see you get 100% market coverage for all US exchanges and unlimited API / WebSocket access. They also have 1min bar historical data (I do not know about the tick level). I can not speak to the quality of the API Access as I have a TotalView subscription. Source: almost 2 years ago

Free tier for researchers, now $99/month for the algotrading access (link: https://alpaca.markets/data). Source: almost 2 years ago

Https://alpaca.markets/data free plan has 200 calls/minute limit which is what you want anyway. Source: over 2 years ago

Has anyone thought about using Digit's bank account? Seems like it has a lot of similar features to One/Simple. I'm definitely intrigued! https://digit.co/. Source: about 2 years ago

Also, just want to point out for anyone else who's reading that I'm not sure how well this would work for microbudgeting — e.g. gas, food, power bill, etc. — feels like that would be tedious to use with this UI. For me, I'm just setting aside rent, an emergency fund, credit card payments, and "fun money" so they're separate from my main balance. It's more like Digit than YNAB. Source: about 3 years ago