TradingView team works hard to make the service better in all aspects every day. Right now we are adding new markets and planning to support more timeframes for existing ones. The result will benefit all our users. To feed our charts with high quality data, we must stay compliant with exchange regulations and rules. According to those rules, only one browser can receive data at a time. That means that now you will need more than one subscription, if you want to access TradingView on more than one device/browser at the same moment.
We understand that for some users it might be convenient to use the same account on multiple devices and we consider allowing multiple subscriptions for one account in the future. Please send us an email to firstname.lastname@example.org if you are interested in such extended account.
Thank you for understanding.