When integrating Cord’s API, it’s worth handling failed responses well to give a good experience.

Error structure

Failed responses return a flat JSON object with two fields:

{
  "error": "Company name is required",
  "code": "invalid_request"
}

• error: a human-readable message you can show or log.
• code: a stable identifier to branch on in your code (e.g. invalid_json, invalid_request).

Common HTTP codes

• 400 Bad Request: a parameter is missing or the JSON is malformed (code: "invalid_request" or "invalid_json").
• 401 Unauthorized: your API key is invalid, revoked, or you didn’t send the Authorization header ("invalid_key", "missing_key").
• 402 Payment Required: your subscription hit the number of API keys included in your plan ("subscription_key_limit"); revoke an older key or upgrade.
• 403 Forbidden: your key lacks the required scope (e.g. using a read-only key for a POST, code "insufficient_scope"), or a publishable key is used from an unauthorized origin/domain ("unauthorized_origin", "missing_origin").
• 404 Not Found: the resource doesn’t exist or doesn’t belong to your organization.
• 409 Conflict: the action doesn’t fit the resource’s current state — for example, voiding an invoice that already has payments applied responds 409 with code: "credit_note_required": the correct document is a credit note instead.
• 413/415: the request body exceeds the size cap ("payload_too_large") or isn’t sent as application/json ("unsupported_media_type").
• 429 Too Many Requests: you exceeded either the request-rate limit or your plan’s monthly quota ("api_quota_exceeded"). See Rate limits.
• 500 Internal Server Error: an error on our side (rare; contact support if it persists).
• 502/503: an external provider the operation depends on didn’t respond — for example, stamping an invoice without being able to prove the exchange rate responds 503 with code: "fx_unavailable" instead of making one up (see the exchange-rate policy in the invoicing documentation).

Note: the v1 API does not process card charges directly; that happens on the Cord public link. Therefore, card-decline errors do not appear in these responses.