Errors & status codes

Errors use standard HTTP status codes and carry a human-readable message inside the same response envelope:

{
  "success": false,
  "code": 400,
  "data": null,
  "error": "Bad request",
  "message": "an active trial account already exists for this email"
}

Always branch on success (or the HTTP status), then surface message to the user.

Status codes

Code	Meaning
200	OK.
201	Created (signup, order placed).
204	No content (cancel, logout).
400	Bad request — validation failed; `message` says which field.
401	Unauthorized — missing/expired token, wrong credentials, expired trial.
403	Forbidden — your scope can't perform this action.
404	Not found.
409	Conflict — e.g. an active trial already exists for the email.
500	Server error.
503	A downstream service (e.g. report generation) is unavailable.

Message	Cause
`not enough margins, order need=…`	Insufficient free margin for the lot size.
`Maximum volume for <SYMBOL> is <n>`	Lot size exceeds the symbol's `volume_max`.
`you can't update market order`	Only pending orders can be modified.
`you can't update the order at this point`	The order isn't in a modifiable state.
`Action not permitted on this session`	Read-only (Investor) scope tried to trade.

WebSocket errors arrive as event frames (bad_request, forbidden, unauthorized, …) — see WebSocket events.