There are a number of choices, depending on what you're trying to accomplish.
Two that come to mind are CoinAPI and Apifiny Connect.
- CoinAPI is a pure connection solution
- Apifiny Connect seems to have what you may be looking for. I'm trading on 5 out of something like 20 exchanges. They all have colocation which they gave me for free, but I'm not sure if that was a special offer. We're using the FIX API. I'd check them both out, depending on what you need. My fees are lower with them than on the exchanges, too.
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Alternative for these platforms is Shrimpy - "The Social Trading Platform for Cryptocurrency. Simplify the way you manage your portfolio by automating your trading strategy" -
https://www.shrimpy.io/.
I checked their demo page and it quite a good, very nice UI. And if you are a developer, or have some knowledge on API, they have Developer's API can be found here:
https://developers.shrimpy.io/They have this demo page, you can check it here:
https://www.shrimpy.io/demoAnd I saw they already have a lot of supported exchanges, most of them are popular crypto exchanges with huge trading volumes.