AS4 is a modern communication protocol for secure and reliable B2B data exchange over the Internet, replacing the need for private networks. With built-in delivery receipts and status tracking, it ensures transparency and accountability in every transaction.

With mendelson AS4, you can transmit EDI data and any type of document — including X12, UN/EDIFACT, XML, and Microsoft Word — without transformation. Data arrives exactly as it was sent.

The solution is fast to deploy and easy to use, whether as a standalone application or fully integrated into the mendelson business integration (mbi) suite.

Built on web services, AS4 is based on the OASIS ebXML Messaging Services (ebMS) v3.0 standard. It expands on AS2 with support for advanced message flows, stronger security, and richer interaction patterns.

Key features of AS4:

• Reliable messaging with delivery acknowledgments and automatic retries
• End-to-end security: password authentication, digital signatures, and encryption
• Support for large file transfers with optional compression
• Flexible interaction models: push and pull messaging, sync and async communication

mendelson AS4 is a turnkey solution supporting the following usage profiles:

• ebMS 3.0 AS4
• ENTSOG AS4
• e-SENS AS4
• PEPPOL AS4 (with automatic service discovery)
• BDEW AS4
• ICS2 AS4

The software supports both push and pull communication, full encryption and signature handling, and TLS 1.3 — making it a secure, future-ready solution. Additional services like EESSI are also supported due to their alignment with e-SENS.

mendelson AS4 enables seamless message exchange with trading partners via HTTP and HTTPS.

A dedicated poll thread runs per partner, monitoring specified directories for outgoing files. Matching files are automatically sent to the mendelson AS4 server. Each partner can also be assigned a dedicated message processing channel (MPC) to handle PULL requests from remote systems.

The following architecture diagram outlines the core components included in the mendelson AS4 installation:

Key Components:

• AS4 Server: Core engine for message processing, encryption, digital signatures, and inter-component communication.
• AS4 Client (Rich Client): Provides user-friendly interfaces for transaction monitoring, partner and certificate management (commercial version only), and system configuration.
• Database: Stores all transaction data and partner information. The commercial version supports an external PostgreSQL database (Professional and Enterprise HA).
• HTTP Server: Hosts the AS4 servlet for incoming messages and optional information pages. A built-in Jetty server is included, but deployment in external servlet containers is also supported.
• AS4 Sender: Handles outbound messages and receives responses and receipts via the backchannel.
• Notification System: Sends alerts via email for events requiring user intervention.

Community vs. Commercial Architecture:

In the community edition, the client and server operate in a single process as a desktop application. In the commercial version, client and server run in separate processes and can operate on different machines — ideal for server deployments and high availability use cases.

The mendelson AS4 solution is available in a dual-license model: a free community edition and three commercial editions — Entry, Professional, and Enterprise HA — tailored to different organizational needs.

Community vs. Commercial Edition

Commercial Editions Comparison

Choose the version that fits your infrastructure needs. Here's a breakdown of the commercial packages:

The Professional and Enterprise HA licenses of mendelson AS4 include the following components – no separate purchase required.

• Java API: Seamlessly embed AS4 messaging functions into your own Java applications without the need for a running mendelson AS4 server. Enables direct access to send/receive operations.
• REST API: Connect mendelson AS4 to web-based environments through a secure RESTful interface. Ideal for integration with modern cloud systems and platforms.
• PostgreSQL Database: Replaces the built-in HSQLDB with an external PostgreSQL server. Includes a data migration wizard. Tested with multiple versions and compatible with cloud-hosted PostgreSQL (e.g., AWS RDS).
• High Availability (HA, Enterprise HA only): Build a scalable AS4 cluster for high availability, load balancing, and performance scaling — whether on-premise or in the cloud. All nodes share one external PostgreSQL database and run the same mendelson version. mendelson software updates are applied to all nodes together in a planned maintenance window.
• OAuth2 Support: Adds OAuth2 authentication for AS4 HTTP message transmission, asynchronous receipt handling, and SMTP-based email notifications.

Core Capabilities

• Full AS4 support including push and pull messaging
• Complete key and certificate management (incl. self-signed and CA-trusted)
• Advanced encryption and digital signature options
• Support for major AS4 usage profiles: ebMS 3.0 AS4, ENTSOG, e-SENS, PEPPOL v1 & v2 (auto-discovery), BDEW, ICS2
• Support for multiple local identities
• Localized UI: English, German, French, Spanish, Italian, Polish, Portuguese
• Comprehensive logging and auto-log cleanup task
• Directory-based partner-specific integration (inbound/outbound)
• Supports message bundling, async and sync receipts

Integration

• Directory polling per partner and scheduler-based processing
• Message scripting on receipt
• Pluggable into any servlet container (Tomcat, Jetty, etc.)
• Integrated Jetty web server included
• Runs on all common platforms, including virtual machines and cloud environments (Java-based architecture)

Monitoring

• Email-based event notification (OAuth2: Professional / Enterprise HA)

Encryption, Signatures & Authentication

Encryption

Supports WSS 1.1 and X.509 Certificate Token Profile.

Encryption algorithms:

• AES (128, 192, 256) incl. GCM variants
• CAMELLIA (128, 192, 256)
• 3DES

Key Transport Algorithms

• RSA v1.5
• RSA-OAEP variants with SHA-1, SHA-2 series
• ECDH-ES with key wrapping (AES128) and SHA-256

Signature

Supports WSS 1.1 [SOAPATTACH], Attachment-Content-Only & Complete Transforms

Signature algorithms:

• RSA, DSA, ECDSA, EdDSA (Ed25519)

Hash algorithms:

• MD5, RIPEMD-160, SHA-1, SHA-2 series

Security Token Authentication

• UsernameToken (wsse:PasswordText)

Certificates

• Supports self-signed and CA-issued certificates
• SHA-1 and SHA-2 signatures

To support your AS4 integration process, mendelson-e-commerce GmbH provides a publicly accessible AS4 test server. It is preconfigured in both the community and commercial installations of mendelson AS4.

The test server helps verify interoperability with your system and is occasionally offline for maintenance. You can check its availability at:

http://testas4.mendelson-e-c.com:8082/as4/ServerState

Server Settings

• Profile: ENTSOG AS4 Profile v3
• Endpoint URL: http://testas4.mendelson-e-c.com:8082/as4/HttpReceiver
• Responder Party: mendelsontestAS4
• Certificates: Key2 (PEM)
• Encryption Algorithm: AES128-GCM
• Signature Algorithm: RSA-SHA256
• Canonicalization: EXC-C14N
• Hash Function: SHA256
• Send Receipt: Enabled with non-repudiation

Your System Settings

• Initiator Party: mycompanyAS4
• Profile: ENTSOG AS4 Profile v3
• Certificates: Key1 (PKCS#12, password: test)
• Encryption & Signing: Enabled for body and attachments
• Role Settings:
  • Initiator: http://docs.oasis-open.org/ebxml-msg/ebms/v3.0/ns/core/200704/initiator
  • Responder: http://docs.oasis-open.org/ebxml-msg/ebms/v3.0/ns/core/200704/responder
• Business Info:
  • Service: http://docs.oasis-open.org/ebxml-msg/as4/200902/service
  • Action: http://docs.oasis-open.org/ebxml-msg/as4/200902/action
  • Service Type: http://edigas.org/service
• Payload Compression: application/gzip

If you experience issues with the test server, please contact us.