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MQL5 trade server return code

MQL5 Error 10030: Invalid order filling type

MQL5 error 10030 is TRADE_RETCODE_INVALID_FILL, the official trade server return code for invalid order filling type. Read SYMBOL_FILLING_MODE for the symbol and select a permitted filling policy. With CTrade, call SetTypeFillingBySymbol before Buy, Sell, or PositionOpen. Read MqlTradeResult.retcode after OrderSend because a successful function return does not by itself mean that the order was executed.

Open MQL5 Coding AgentReview the diagnostic example

Open the Coding Agent and choose MQL5 from the language menu.

Check retcode 10030.mq5
#include <Trade/Trade.mqh>

CTrade trade;

bool BuyWithSymbolFilling(const string symbol, const double volume)
  {
   if(!trade.SetTypeFillingBySymbol(symbol))
     {
      Print("Cannot select a filling mode for ", symbol);
      return false;
     }

   bool sent=trade.Buy(volume,symbol);
   PrintFormat("sent=%s retcode=%u %s",
               sent ? "true" : "false",
               trade.ResultRetcode(),
               trade.ResultRetcodeDescription());
   return sent;
  }
  • Official code: TRADE_RETCODE_INVALID_FILL
  • Meaning: Invalid order filling type
  • Layer: trade server response
  • Verify: MqlTradeResult.retcode

Also searched as: mt5 error 10030 unsupported filling mode.

What error 10030 actually reports

The code belongs to MqlTradeResult.retcode, not to the compiler error list and not necessarily to GetLastError. The trade server uses 10030 to report invalid order filling type.

Keep the request, the boolean returned by OrderSend, result.retcode, result.comment, and the symbol properties in the same log record. That separates a client-side request failure from a server-side rejection.

Inspect the request before changing the strategy

Use the smallest failing order and compare every broker-sensitive value with the current symbol and account. Do not hide the error by retrying unchanged input.

  • Compare request.type_filling with SYMBOL_FILLING_MODE.
  • Do not assume that FOK, IOC, or RETURN is accepted for every symbol.
  • If CTrade builds the request, set its filling policy for the current symbol.
  • Log the exact broker symbol because symbol settings are server-specific.

Repair and verify

Read SYMBOL_FILLING_MODE for the symbol and select a permitted filling policy. With CTrade, call SetTypeFillingBySymbol before Buy, Sell, or PositionOpen.

Run OrderCheck with the completed request, log its retcode and comment, then send only if the check is acceptable. OrderCheck improves diagnostics but does not guarantee execution.

Use a focused diagnostic

The example delegates filling-policy selection to CTrade using the current symbol settings, then logs the server retcode instead of relying on the boolean alone.

A valid request can still be rejected or filled differently by the trade server. Check the returned retcode, test with the broker symbol and account, and review risk before any live order.

Check retcode 10030.mq5
#include <Trade/Trade.mqh>

CTrade trade;

bool BuyWithSymbolFilling(const string symbol, const double volume)
  {
   if(!trade.SetTypeFillingBySymbol(symbol))
     {
      Print("Cannot select a filling mode for ", symbol);
      return false;
     }

   bool sent=trade.Buy(volume,symbol);
   PrintFormat("sent=%s retcode=%u %s",
               sent ? "true" : "false",
               trade.ResultRetcode(),
               trade.ResultRetcodeDescription());
   return sent;
  }
Where Pineify fits

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A practical verification workflow

  1. 1

    Capture the complete result

    Log the OrderSend return value, result.retcode, result.comment, symbol, order type, volume, price, stops, and filling mode. Confirm that the retcode is 10030.

  2. 2

    Read current constraints

    Query the symbol and account immediately before building the request. Broker constraints can differ between symbols and sessions.

  3. 3

    Change the invalid field

    Read SYMBOL_FILLING_MODE for the symbol and select a permitted filling policy. With CTrade, call SetTypeFillingBySymbol before Buy, Sell, or PositionOpen.

  4. 4

    Check, send, and retest

    Call OrderCheck, submit the corrected request, then reproduce it in Strategy Tester and a demo account before considering live use.

Frequently asked questions

What does MQL5 error 10030 mean?

It is TRADE_RETCODE_INVALID_FILL, the official MQL5 trade server return code for invalid order filling type.

Is 10030 a GetLastError code?

Treat it as a trade server return code when it appears in MqlTradeResult.retcode. GetLastError reports the terminal runtime error layer, which is a separate diagnostic channel.

Does OrderSend returning true mean the trade executed?

No. The official OrderSend reference says true means the request passed basic checks and was accepted for processing. Inspect result.retcode and subsequent trade events to determine the outcome.

Last verified against the linked official references on . Compile and test the final source in the MetaTrader 5 build, broker, symbol, and account environment you plan to use.

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