Агрегаторы
https://www.cryptocompare.com/api/
https://apiv2.bitcoinaverage.com/
hitbtc.com
https://github.com/hitbtc-com/hitbtc-api/blob/master/APIv1.md
https://packagist.org/packages/dzarezenko/hitbtc-api
https://gemini.com/api-agreement/#welcome-to-the-gemini-api
https://docs.gemini.com/rest-api/
https://docs.gdax.com/
https://packagist.org/packages/mrteye/gdax
https://www.kraken.com/help/api
https://github.com/payward/kraken-api-client/tree/master/php
https://docs.bitfinex.com/docs
https://github.com/mariodian/bitfinex-api-php
bitstamp.net
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