Where and how is it better to take the exchange rates of Russian banks?

Question

Payment systems

Good day!
I need up-to-date information on exchange rates of Russian banks. Here's the best place to get it.
If from some services, then the course will be received with a delay (until the service asks for information, later my site will contact the service). But if you parse directly from bank sites, then you need to write regular expressions for each site, plus, for a long time to collect all the information. And banks update the rate throughout the day.
I will also clarify, I plan to store the exchange rates of different cities (i.e. the rate in the city of Omsk may differ from the rate in Moscow).
If you parse from the service, you need to bypass all the pages by city. If from the sites of banks - each site + each city of the bank.
Will banks/services ban me for such parsing? Maybe I somehow think wrong, then tell me how such services collect information.
And further. What kind of services do you know (preferably with API).