Token salah menghasilkan 401, scope kurang 403. createInvoice wajib amount (>0, maks. 2 desimal) dan menerima deskripsi 1–256, catatan 160, payload, expires_in 60–86.400 (default 1.800), serta tombol pascapembayaran. getInvoice mencari payload dulu; getInvoices 50/halaman; cancelInvoice membatalkan yang aktif (deleteInvoice alias); getStats membaca periode.
Idempotency-Key berisi 1–128 karakter huruf, angka, -_.:. Replay sama mengembalikan tagihan awal; berbeda menghasilkan 409. Error utama: INVALID_AMOUNT, INVALID_PARAMS, ROUTE_NOT_AVAILABLE, INVOICE_NOT_FOUND, INVALID_STATUS. 402 account_not_serviceable memakai error, message, billing di tingkat atas. Nilai uang berupa string; status active, paid, expired, cancelled.