Errors

Every error is a JSON body of exactly two fields with the HTTP status Binance would use:

{ "code": -2010, "msg": "Account has insufficient balance for requested action." }

CCXT's binance class maps code to its typed exceptions (AuthenticationError, InsufficientFunds, InvalidOrder, OrderNotFound, RateLimitExceeded, BadSymbol, ...), so try / catch written for Binance works unchanged.

Codes

HTTP	code	msg	What to do
401	`-2015`	Invalid API-key, IP, or permissions for action.	Missing `X-MBX-APIKEY`, revoked key, or signature mismatch. Check the secret and the signed bytes.
400	`-1021`	Timestamp for this request is outside of the recvWindow.	Sync your clock or raise `recvWindow` (max 30000).
400	`-1102`	Mandatory parameter 'timestamp' was not sent...	Add `timestamp`.
400	`-1131`	recvWindow must be less than 30000	Lower `recvWindow`.
400	`-2010`	This key is bound to a SPOT strategy; use /api/v3	Wrong family for this key.
400	`-2010`	Strategy not live	No strategy bound, or a write against a strategy that is not LIVE.
400	`-2010`	Account has insufficient balance for requested action.	Reduce size; check `free` in the account response.
400	`-1121`	Invalid symbol.	Not in Wellat's `exchangeInfo`.
400	-4161	Leverage reduction is not supported in Isolated Margin Mode with open positions	Close or reduce the position first.
400	`-1116`	Invalid orderType.	Use a type the symbol advertises.
400	`-1102`	Bad or missing parameter	Includes sizing and precision failures: round to `stepSize` / `tickSize` and meet `minNotional` from `exchangeInfo`.
400	`-2013`	Order does not exist.	Wrong `orderId` or `origClientOrderId`.
400	`-2011`	Unknown order sent.	Cancel of an order that is already filled or cancelled.
400	`-4120`	Conditional order type not allowed on /fapi/v1/order	Use `/fapi/v1/algoOrder` for STOP / TAKE_PROFIT.
429	`-1003`	Too many requests...	Back off per `Retry-After`. See Rate limits.
429	`-1015`	Too many new orders...	Slow down order placement.
418	`-1003`	Way too much request weight used; banned until ...	Stop for two minutes.
404	`-1000`	Unknown route	The path is not part of the Bot API.
413	`-1000`	Request body exceeds the 10240 byte limit	Bodies are small form strings; something is wrong with the client.
503	`-1001`	Internal error; unable to process your request. Please try again.	Wellat could not reach its trading engine in time. Retry with the same `newClientOrderId`.

Retrying safely

Wellat never retries a request on your behalf. On a timeout or a 503 you do not know whether an order was placed. Always send newClientOrderId (or clientAlgoId for futures legs) and retry with the same value: a duplicate returns the existing order rather than placing another. Reads are always safe to retry.

What never comes back

No error body is wrapped in { status, message, data } or any other envelope. If you see one, you are not talking to the Bot API.