Errors

Errors are returned as JSON with a stable type code:

{
  "error": {
    "type": "subscription_required",
    "message": "An active subscription is required to use the payment API."
  }
}

Error types

HTTP	Type	Meaning
401	`authentication_error`	Missing, invalid, or revoked API key.
402	`subscription_required`	No active subscription.
402	`transaction_limit_reached`	Plan limit for the billing period used up.
403	`merchant_suspended`	Account suspended — contact support.
403	`domain_not_allowed`	Request came from a browser origin not in your allowed domains.
404	—	Unknown payment reference (or owned by another merchant).
422	—	Validation failed; see the `errors` object.
429	—	Rate limited (120 requests/minute per key).

Payment failure reasons

Failed payments carry a failure_reason: duplicate_trx_id (the TrxID was already used to verify another payment) or rejected_by_admin (manually rejected after review).