EA, API or browser: how a trade copier connects

A trade copier has to place orders on your accounts. There are three ways to do it, and the choice decides how fast copies are, what has to stay running, and whether a prop firm's technical restrictions get in the way.

Expert Advisor (EA) in your terminal

The copier gives you a small program that runs in your MetaTrader 4 or 5 terminal. It reads the source's trades or places the copies itself.

• Pros: works with any MT4/MT5 broker; orders come from your own terminal, as if you traded by hand.
• Cons: the terminal must stay open (a computer or a VPS); you update the EA when a new version comes out.

The broker's API

The copier connects to the platform directly: cTrader, TradeLocker, DXtrade, or MetaTrader through a service such as MetaApi.

• Pros: nothing to keep running on your side; fast and robust; positions are tracked by their exact id.
• Cons: the broker or prop firm must allow API access. Some block it on purpose.

A browser session

When there is no usable API, the copier drives the platform's web interface the way a person would (MatchTrader in HydraSync's case).

• Pros: works where API access is closed.
• Cons: the slowest of the three, heavier to run, and a redesign of the broker's site can break it until it is adapted.

What it means for prop firms

Separate two questions: is copy trading allowed by the firm's rules, and does the connection work technically. A firm can allow copying while blocking API access, or the reverse. Before connecting a funded account, read the firm's rules, then pick the connection that matches them. More in Prop firms and Supported platforms.

FAQ

Which is the fastest?

Usually the API, then the EA, then the browser.

Can I mix them?

Yes. A source on an EA can feed destinations on APIs and the other way round.

Does the EA need my password?

No. It runs inside your terminal, which is already logged in. API connections need the platform's credentials or a token.