Public API
The Public API is the internet-facing interface for creating and processing eInvoices with Klik Račun. Behind Klik Račun is IIProxy, the underlying informational intermediary system that integrations use through the Public API. Each client is restricted to the organization bound to its credential. The API is intended for server-side integrations such as ERP and point-of-sale systems.
It supports structured JSON and raw UBL 2.1/HR-CIUS XML, validation before issuance, AS4 delivery, fiscalization, eReporting, guarded corrections and reversals, advances, payment evidence, and incoming-invoice responses.
The Public API is available at https://iiproxy.sekkun.co/public/v1.
Security model
Every client is bound server-side to one issuer profile, OIB, permission set, and default revenue account. A supplier OIB in the request body is not authorization and cannot switch organizations.
Every mutation requires an Idempotency-Key. Long-running actions return an operation resource instead of assuming that an external system accepted the document.
UBL XML is not FIS XML
Clients send a business UBL Invoice or CreditNote. IIProxy derives and signs the fiscalization request using its own authority. The Public API never accepts a prebuilt Tax Administration FIS request from a client.
Next: Quick start.