Issue invoices in third-party invoicing
Once the delegated connection is live (the supplier approved the request), the delegate issues invoices in the supplier's account - on the web UI or via Számla Agent. The good news: delegated invoicing barely differs from what you are used to:
- Invoicing on the UI? Log in with the dedicated user and invoice the same way as in your own account; details in the Invoicing on the UI section.
- Invoicing via Agent? Send the standard invoice XML with the login credentials (username + password) of the dedicated (
usrMb) user given at connection time; the only thing to watch is the invoice prefix; details in the Invoicing via Számla Agent section.
Establishing the connection: in the UI or via API; roles and the business overview: Third-party invoicing.
Prerequisites
- The delegated connection is approved; see Establish the connection in the UI or Establish the connection via API.
- For Agent-based issuing, you use the credentials (username + password) of the dedicated login user.
- The NAV Online Számla connection is completed for the supplier account.
- Supplier-specific invoice book/prefix is agreed; see Invoice prefix handling.
If these are in place, you can start.
Before going live, the whole delegated flow can be tried risk-free with test accounts; see Testing the flow.
What changes compared to standard invoicing?
The short answer: almost nothing. The system recognises the delegated context from the login: the dedicated user belongs to the supplier's account as a delegated user - everything else works the usual way.
- The seller on the invoice is always the supplier (megbízó) company.
- The invoice is stored in the supplier's account; the supplier sees it like any of their own invoices.
- The cost bearer of the issuing is the delegate: the service has a fixed monthly fee, plus the fees of bulk invoicing or the Számla Agent (if used) as variable costs; current pricing is on the Megbízott számlakibocsátás product page (Hungarian). The available document types and features follow the delegate's subscription plan.
Invoicing on the UI
Invoicing on the UI does not differ from standard invoicing: logged in with the dedicated user, you issue the invoice in the supplier's account on the same invoicing screen, the same way as in your own account. You cannot even pick a wrong invoice book: as a delegated user, the system only offers the delegated invoice books tied to your company.
If the dedicated user has access to more than one account (for example to the delegate's own account too), check in the account selector after login that the supplier's account is selected - the invoice is always created in the currently selected account.
Invoicing via Számla Agent
Nothing changes in the XML. Delegated invoices are created with the standard invoice-generating XML (xmlszamla, action-xmlagentxmlfile), using the login credentials (username + password) of the dedicated (usrMb) user given at connection time; there is no dedicated "delegated" field, and no seller data needs to be provided. See Invoice XML for the full schema.
A Számla Agent key always belongs to an account, not to a user, so it does not carry the delegated relation: a document submitted with a key created in the supplier's account would be issued under the supplier's own name, without the delegated marking and delegated cost bearing. This is true even if you generate the key while logged in to the supplier's account with the dedicated delegated user: the key is always created as a separate, account-level technical user, and it does not inherit the delegated relation of the user who generated it. For delegated Agent calls, always use the username + password pair of the dedicated user.
Invoice prefix
The invoice book decides who the invoice belongs to: as a delegate you may only use invoice books tied to your company. Which book the invoice goes to is decided by the <szamlaszamElotag> field:
- If you send the agreed delegated prefix, it is used.
- If you send no prefix and you have exactly one delegated invoice book, the invoice is automatically created with the prefix assigned to your delegate company.
- Other combinations either fail with a specific error or register a new prefix.
The complete decision tree, including all edge cases: Invoice prefix handling - decision tree.
Response
The response follows standard Agent invoicing: invoice number in the szlahu_szamlaszam header, PDF in the body if requested. See Invoice response.
Common errors
| Code | Message (HU) | Meaning and what to do |
|---|---|---|
| 3 | Sikertelen bejelentkezés. | Login failed: wrong credentials. Make sure you call with the dedicated user's credentials. |
| 164 | Ez a felhasználó (név) több számlázási fiókhoz is hozzáfér, így a funkció nem üzemképes. | Agent calls require a user with access to exactly one account; use the dedicated (usrMb) user. |
| 354 | Ez a számlaszám előtag nem használható. | The given prefix cannot be used by your delegate company (for example it belongs to another delegate, is a receipt-type prefix, or already has invoices). Use your agreed delegated prefix. (A disabled invoice book results in error 202, not this one.) |
| 356 | A megadott számlaszám előtag helyett használd ezt: (előtag). | You already have a delegated invoice book with this supplier; use the prefix returned in the message. |
| 357 | Kérjük, add meg a számlaszám-előtagot. | You sent no prefix and it cannot be selected automatically; send the agreed prefix in <szamlaszamElotag>. |
Full list with resolutions: Error handling.
Restrictions on invoice operations and visibility
This section is about follow-up operations - storno, correction, repeat - so it typically becomes relevant later, not when issuing your first invoice.
Invoices are separated by invoice book (prefix): delegated invoice books belong to the delegate, other invoice books to the supplier. The follow-up operations respect this separation:
| Operation | Delegate on supplier's invoice | Supplier on delegate's invoice |
|---|---|---|
| Storno (reverse) | The delegate cannot reverse the supplier's own invoices; the call fails with error 358. | The supplier cannot reverse delegated invoices; the error 359 message names the delegate to ask for the reversal. |
| Correction | The delegate cannot correct the supplier's own invoices; the call fails with error 493. | The supplier cannot correct delegated invoices; the error 494 message names the delegate to ask for the correction. |
| Repeat (recurring) | Delegated users cannot repeat invoices at all; the call fails with error 17. | The supplier cannot repeat delegated invoices; the error 489 message names the delegate. |
In short: delegated invoices are managed by the delegate, the supplier's own invoices by the supplier.
Visibility follows the same logic:
- the supplier sees all invoices in the account (including the delegated ones),
- the delegate sees only the invoices issued by the dedicated user.
Next step
Delegated issuing also covers receipts, with the same connection model: Issue receipts in third-party invoicing.