Checking order return codes in MQL5: the minimum

[FXS London Scalper]

A surprising number of EAs send orders without checking whether they worked. In MQL5 the information is all there; it just needs to be read.

The minimum:

• Check the return value of OrderSend. False means the request didn't reach the server or failed a local check.
• Read the result structure's retcode. TRADE_RETCODE_DONE means filled; anything else needs handling.
• Log the retcode with a short description, the requested price and, if filled, the fill price.

Common codes worth handling:

• Requote and price changed: retry once with a fresh price, or skip.
• Invalid stops: the stop is too close; check stop level and recalculate.
• Market closed: stop trying until the session reopens.
• No money: reduce size or stop; never loop.

The worst pattern is a loop that retries forever. Limit retries to one or two, with a short pause, and then log and give up.

A simple test: on demo, deliberately send an order with a stop inside the stop level and check that the EA logs and handles it.

These basics matter more than clever entry logic, because a silent failure can leave the account exposed without anyone noticing.

Which return codes caused you trouble?