Errors

Errors are returned as JSON with an error message and the matching HTTP status.

{ "error": "side must be BUY or SELL" }

Status	Meaning	Typical cause
`400`	Bad request	Unsupported pair, bad `side`, non-positive `amount`, or invalid JSON
`401`	Unauthorized	Missing or invalid API key
`403`	Forbidden	API key revoked
`429`	Too many requests	More than one request per 5s for the key (see Rate limits)
`503`	Service unavailable	No price available right now — retry shortly

A 200 response always contains a full quote (or the rates list).