How to Register for Hungary's NAV Online Számla: Setup & API Guide

Registering for Hungary's NAV Online Számla requires an active Hungarian tax number (adószám), access to the NAV portal, and configuration of a technical user for API reporting. The setup process takes 1-3 business days and includes a test environment for validation before going live.

Prerequisites

Prerequisites includes: Active adószám: Hungarian tax identification number (format: XXXXXXXX-Y-ZZ) NAV portal access: Ügyfélkapu (Government Gateway) credentials for the company's authorized representative

• Active adószám: Hungarian tax identification number (format: XXXXXXXX-Y-ZZ)
• NAV portal access: Ügyfélkapu (Government Gateway) credentials for the company's authorized representative
• Invoicing software: System capable of generating NAV XML 3.0 and connecting to the API

Step-by-Step Registration

Step 1: Access the NAV Online Számla Portal

Navigate to onlineszamla.nav.gov.hu and authenticate with your Ügyfélkapu credentials.

Step 2: Register Your Company

Enter your company's adószám (8-digit tax number). NAV automatically verifies your registration and links it to your company data.

Step 3: Create a Technical User

1. Navigate to "Technikai felhasználó kezelése" (Technical User Management)
2. Create a new technical user with a unique username
3. Set a password meeting NAV's complexity requirements
4. Generate the XML signature key (aláíró kulcs) — this is used for HMAC-SHA512 request signing
5. Generate the XML exchange key (cserekulcs) — used for AES-128 encryption
6. Save all credentials securely — the signature and exchange keys cannot be retrieved later

Step 4: Configure API Connection

• Production endpoint: https://api.onlineszamla.nav.gov.hu/invoiceService/v3/
• Test endpoint: https://api-test.onlineszamla.nav.gov.hu/invoiceService/v3/
• Authentication: Technical user credentials + HMAC-SHA512 request signature

Step 5: Test in Sandbox

1. Submit test invoices to the test endpoint
2. Verify successful acceptance and response handling
3. Test error scenarios (duplicate invoices, invalid data)
4. Validate modification and cancellation workflows

Step 6: Go Live

Switch your invoicing software to the production API endpoint and begin real-time reporting.

Managing Multiple Technical Users

Managing Multiple Technical Users includes: You can create multiple technical users for different software systems Each technical user has independent credentials and keys

• You can create multiple technical users for different software systems
• Each technical user has independent credentials and keys
• Permissions can be limited (e.g., reporting only, no query access)

How Invoicemonk Simplifies NAV Setup

Invoicemonk requires only your adószám and technical user credentials to begin automated NAV reporting. Our system handles API authentication, XML generation, and real-time submission — no manual API configuration needed.