IPN messages
💵 Invoice payment status updates
There is an option for the web store (or other business application) to receive notifications about the payment status of a document (invoice or pro forma invoice) via IPN (Instant Payment Notification).
This message is sent by Számlázz.hu to the specified web address as an HTTP POST request. The URL can be specified within the billing account on the Fiók beállítások / Számlázás alapadatok page.
The detailed IPN description is available in the Számlázz.hu knowledge base.
⏰ When is the IPN message sent?
The IPN message is created when:
- The paid amount of a document (invoice or pro forma invoice) changes (e.g., partial or full payment occurs)
- The change occurs on the document issuer's side
- The company has a configured IPN URL
Payment of a pro forma invoice
- If the "Díjbekérő automatikus számlázása" (automatic invoicing of pro forma invoices) setting is enabled, an invoice is issued from the paid pro forma invoice, the payment is recorded on the invoice, and the IPN is sent about the invoice. In this case
szlahu_szamlaszamis the invoice number,szlahu_dijbekero_szamais the pro forma invoice number, andszlahu_rendelesszamis the order number inherited from the pro forma invoice. - If the setting is disabled, or a bank transaction smaller than the full amount is manually paired with the pro forma invoice, no invoice is issued, and the IPN is sent about the pro forma invoice. In this case
szlahu_szamlaszamis the pro forma invoice number, andszlahu_dijbekero_szamais empty.
📋 IPN message parameters
The IPN message contains the following parameters:
| Parameter | Description | Example |
|---|---|---|
szlahu_szamlaszam | The number of the document (invoice or pro forma invoice) | E-2020-123 |
szlahu_dijbekero_szama | For an invoice issued from a pro forma invoice: the pro forma invoice number; otherwise empty | DB-2020-456 |
szlahu_rendelesszam | Order number (if included on the document) | RND1234 |
szlahu_bruttovegosszeg | The gross total amount of the document | 10000 |
szlahu_kifizetettbrutto | The total amount paid on the document so far (not the last payment) | 10000 |
szlahu_fizetesmod | The payment method | kp, bankkártya, átutalás |
szlahu_kifizdat | The payment date (YYYY-MM-DD) | 2025-05-14 |
The szlahu_kifizdat IPN message is not activated by default. If you wish to utilize this feature, our customer service team will be happy to assist you in setting it up. Please contact our customer service representatives!
💻 Technical implementation
IPN message format
IMPORTANT: IPN message data is sent in the HTTP POST request body. The message arrives with application/x-www-form-urlencoded content type.
Response requirement
The receiving system must send an HTTP 200 OK response to indicate successful processing. The response body content is not relevant, only the HTTP status code matters.
The IPN sends the state of the document, not an event
The IPN contains the state of the document at the time of sending: szlahu_kifizetettbrutto is the combined amount of all payments so far, not the last payment. Therefore, overwrite the values on the receiving side instead of adding them to the previous ones. This way, a delayed or repeated IPN does not cause a discrepancy.
Authentication
The IPN request contains no signature or other authentication data. In addition to IP filtering, we therefore recommend putting a secret token known only to you into the IPN URL (over HTTPS), and querying the document with the action-szamla_agent_xml call when the IPN arrives, to verify the data.
⚠️ Important notes
Retry mechanism
IPN messages are not sent immediately: the system sends the pending payment information every 3 minutes. Whether a failed sending is retried depends on whether an HTTP response was received from the receiving server:
- An HTTP response is received, but not 200 (for example 301, 403, 404, 500, 503): the sending is closed, the system records the received status code, and the IPN is not sent again.
- No HTTP response is received (timeout, connection refused, DNS error, dropped connection): the system retries sending. At most 11 attempts are made in total (1 sending and 10 retries), after which the IPN is discarded.
Do not return an HTTP code other than 200 on error in the belief that you will receive the IPN again later, because the system does not resend it in this case. If processing fails on your side, you can query the current state of the document with the action-szamla_agent_xml call.
IPN message accumulation
IPN requests may accumulate in the sending system (Számlázz.hu), especially during high traffic. These messages are automatically sent to the receiving system over time. The system only picks up IPNs that were created or last attempted within the past 5 days; older ones are no longer sent.
Duplicate message handling
The system ensures that only one active IPN message exists per document at a time. If multiple IPN records belong to a document, only the latest one is sent, and the others are automatically deleted.
🌐 IP addresses and network settings
IPN messages are sent from the following IP addresses:
3.73.214.98
3.76.149.232
18.153.156.51
If you use IP-based filtering, add these addresses to your whitelist.
The previous IP addresses (18.153.1.171, 3.73.114.72, 52.59.28.5) are no longer used from August 1, 2025.
Detailed information: Technological changes 2025