This is some information about MetaTrader.

MetaTrader is an all in one concept: You get free software for charting, market analysis, backtesting, manual- and robot trading and free market data along with history data.

Therefore, you trade only with the MetaTrader Broker connected to your MetaTrader client.

The MetaTrader broker usually charges you by commissions and / or
the costs imposed by an artificial spread.

Spread : The difference between lowest Sell Offer =Ask and highest Buy offer=Bid.

This way, MetaTrader brokers can always do a posititive deal. This is also the reason, why there is no market data API in the client, because MetaTrader broker need to have control about market data for their business concept.

So it is not possible to feed MetaTrader charts or internal data containers  with external data. You may can patch the history data, but this is tricky and not recommendable.

MetaTrader is powerful tool and traders can get in by very low costs. As good as it sounds, you should always be aware that MetaTrader brokers want to earn money with it and someone has to lose to do so.

Sometimes poeple find commissions to high or orders executed for bad prices. This is where trade-commander.con can help with bridging products to InteractiveBrokers (IBKR). IBKR has no artificial spread, no dealing desk. You get directly on the markets.

Interactive Brokers enjoys a good reputation and also they want to earn money.  But they do this only with fixed commissions, which are charged for each order. This is a big difference.