Errors & rate limits

Errors

A wrong or missing API key returns HTTP 401 with UNAUTHORIZED (see Authentication). A read-only fxs_ro_ key returns HTTP 403 with READ_ONLY_KEY on the trading routes and on any method other than GET or HEAD. An unknown path returns a plain 404 from the edge. Everything else comes back in the same envelope: an error code, a message, and a command_id for log correlation. The code is fixed, so branch on it, never on the message:

{
  "error": "MRPC_UNKNOWN_SYMBOL",
  "message": "unknown symbol: EURUSDX",
  "command_id": 19
}

Two of these tell you whether a trade ran. MRPC_ABANDONED means it didn't, so sending it again is safe. MRPC_TRADE_OUTCOME_UNKNOWN means it may have, so never resend that order blindly. Send every order with a clientOrderId and the question goes away: a repeat with the same id never trades twice and returns the first reply instead (see Trading).

cTrader Trade Errors and Their Retcodes

A rejected order is not an error response: the request worked, the broker said no. It comes back as HTTP 200 with success: false. cTrader names its refusals with codes such as NOT_ENOUGH_MONEY, so the bridge translates each into the matching MT5 retcode and puts cTrader's message in comment. Your code can branch on the same retcodes for cTrader, MT4 and MT5 accounts:

{
  "success": false,
  "outcome": "rejected",
  "retcode": 10014,
  "retcodeDescription": "Invalid volume",
  "deal": 0,
  "order": 0,
  "comment": "volume 0.015 is not a multiple of 0.01 lots from 0.01 to 100",
  ...
}

A successful market order reports 10009 (Done), a placed pending order 10008 (Placed). outcome sums the result up as applied, no_change (retcode 10025, safe to treat as applied), partial or rejected. A volume off the symbol's step (10014), a pending price on the wrong side of the market (10015) and a modify that changes nothing (10025) are answered by the bridge before anything goes to cTrader.

Orders cTrader cannot take the way MetaTrader means them never reach the broker: a stop-limit order (BuyStopLimit, SellStopLimit) and execution: "Manual" are answered with HTTP 400 and MRPC_VALIDATION, with the reason in message.

Rate Limits

cTrader accounts reach Spotware through FxSocket's connections to the Open API, which limits requests per connection, history requests most tightly. The bridge paces requests within those limits, so a burst waits a little rather than failing, and it keeps closed bars, so asking for the same price history again costs nothing. A trade that cTrader still refuses for frequency comes back as retcode 10024. Platform routes under /v1 are rate limited per API key: if you exceed a limit you get a 429 with a Retry-After header, so wait that long and retry. For live prices, positions, or account changes, prefer the WebSocket streams over polling: you get pushed updates without burning round-trips.