Handling Trade Server Errors with Retries in MQL5

Summary

This article explains how an MQL5 trading library can respond to errors returned after submitting an order request. It groups responses by the action they call for: continue after acceptance, disable trading, stop the current method, correct request parameters, refresh market or account data, wait before retrying, or create a pending request for later handling. The pending-request case is deferred to a later installment.

The proposed flow retries eligible requests up to a configured attempt limit, stopping early if the server accepts the order and returning failure if attempts are exhausted. The caller can then inspect the final server error. The implementation also adds account-mode access and flags for particular pending-order and stop-limit price errors. This is a library implementation guide rather than a trading study: it gives no measured reliability or execution results, and retry behavior depends on correctly classifying which server responses are safe and useful to retry.

Key ideas

• Server responses should be mapped to explicit actions such as stopping, correcting, refreshing, waiting, or retrying.
• The library retries eligible order requests until acceptance or exhaustion of the configured attempts.
• If all attempts fail, the trading method returns failure so the caller can inspect the last error.
• Some errors require corrected request values, while others call for refreshed data or a delay.
• Pending request handling is identified as future work in the series.

Tags

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.