White PaperAS4 is a web-services-based message protocol for securely exchanging B2B messages between trading partners. It was developed by OASIS for ebXML Messaging Services.
What Is AS4?
AS4, or Applicability Statement 4, is a web-services-based message protocol for securely exchanging B2B messages between trading partners. Developed by OASIS for ebXML Messaging Services, AS4 supports the exchange of business payloads such as EDI and XML. For SEEBURGER customers and integration teams, AS4 is relevant for B2B/EDI communication scenarios that require interoperable, secure and reliable message exchange, including sector-specific profiles such as MaKo AS4 in the German energy market.
Key takeaways
- AS4 is similar to AS2 by design, but it works in a web services context and supports stronger interaction patterns, delivery notifications, and recipient-side message pulling.
- AS4 uses security, reliability, interoperability, and payload independence to support structured B2B message exchange.
- AS4 is used in markets and sectors with service-oriented B2B messaging requirements, including retail, healthcare, utilities, Peppol, ENTSOG, EPREL, e-CODEX, JEITA, Superstream Pensions, and IATA-related scenarios.
What is AS4 used for?
AS4 is used to exchange B2B messages securely between trading partners. The protocol can carry different types of payloads, including EDI and XML, and is designed for interoperable message exchange based on the OASIS standard for ebXML Messaging Services.
How does AS4 compare with AS2?
AS4 and AS2 are similar by design. During AS4 development, AS2 advantages were analyzed and used as inspiration. Compared with AS2, AS4 works within a web service context and provides improved interaction patterns and delivery notifications. AS4 also allows the recipient to actively pull messages because the AS4 server is permanently active.
Which features define the AS4 messaging standard?
- Interoperability: AS4 is defined based on the OASIS standard.
- Security: AS4 uses a subset of web services security features to support non-repudiation and data confidentiality.
- Reliability: AS4 exchanges confirmations to support one-time delivery.
- Payload independence: AS4 can exchange different payload types, including EDI and XML.
What does an AS4 Messaging Service Handler do?
The AS4 Messaging Service Handler, or MSH, sets up the AS4 message exchange with the remote station on the sending or receiving side. It must communicate with the remote station according to AS4 specifications and connect with the internal business application.
Which message types does AS4 use?
The ebMS 3.0 specification defines user messages and signal messages within the AS4 usage profile.
| AS4 message type | Purpose |
| User Message | Contains the business payload exchanged between the business applications of two parties. |
| Signal Message: Receipt | Confirms that the receiving MSH could analyze the incoming message. |
| Signal Message: Error | Confirms that the receiving MSH encountered a problem while parsing the incoming message. |
| Signal Message: Pull request | Supports the pull message exchange pattern. |
Where is AS4 used?
AS4 is increasingly used in markets with service-oriented architecture for B2B messaging. The existing AS4 examples include retail, healthcare, utilities, and regional usage profiles in Europe, Japan, Australia, and worldwide contexts.
| Area | Examples |
| Europe | Peppol, e-CODEX, ENTSOG, EPREL |
| Japan | JEITA |
| Australia | Superstream Pensions |
| Worldwide | IATA |
What advantages does AS4 provide?
The message source is clearly defined by digital signatures
Encryption supports data security
Delivery notification receipts provide proof of timely delivery
AS4 supports large file compression and file transfer scenarios
Frequently asked questions about AS4
What is AS4?
How is AS4 different from AS2?
AS4 is similar to AS2 by design, but it works in a web service context, provides improved interaction patterns and delivery notifications, and supports recipient-side message pulling.
What payloads can AS4 exchange?
AS4 can exchange different payload types, including EDI and XML.
How does AS4 confirm delivery?
AS4 supports reliability through confirmations. Delivery notification receipts provide proof of timely delivery, and a non-repudiation receipt indicates successful delivery in AS4 communication.
What is an AS4 Messaging Service Handler?
An AS4 Messaging Service Handler sets up the AS4 message exchange with the remote station on the sending or receiving side and connects AS4 communication with an internal business application.
Where is AS4 used?
AS4 is used in markets with service-oriented B2B messaging requirements, including retail, healthcare, utilities, Peppol, e-CODEX, ENTSOG, EPREL, JEITA, Superstream Pensions, and IATA-related contexts.
What is needed for MaKo AS4 communication?
MaKo AS4 communication requires an AS4 adapter that supports ECC Brainpool, a Hardware Security Module where private keys are generated and stored, and certificates from the BSI Smart Meter PKI.
How can organizations connect to the SEEBURGER AS4 Cloud Service?
Organizations can connect to the SEEBURGER AS4 Cloud Service using AS2 or a REST API.
Related topics
Good to Know
AS2 (Applicability Statement 2) is a http based protocol to transmit messages (especially EDI messages) safely, cheaply and quickly. In the last 20 years AS2 has become the most widely used protocol for EDI in many industries, such as the retail and the consumer goods industry.
What Is AS2 and Why Is It Important for EDI?
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