My Exchange tells me not to share API keys with any third party?
This is good advice, and in general you should always be careful with whom you share your API keys. Unfortunately, we cannot retrieve data about your account without an authorization from you, either by API key or by Oauth login.
Similar to how some apps connect to your bank accounts with a username and password, we use these API keys to retrieve information from your exchange. You can always set the least amount of permissions you're comfortable giving us, for instance, letting us read balances but not letting us place trades or make withdrawals.
We store your information with bank-level security, and we will delete it immediately upon your request. We are also registered with the SEC as an investment adviser, so we have to keep the federal government updated on our activities.
If you would like to read more about our security practices, you can get more information at our security page.