What is ARXML?

If you work in AUTOSAR-based development, ARXML is one of the first file formats you encounter. Short for AUTOSAR XML, files with the .arxml extension are the standard XML-based format that the AUTOSAR ecosystem uses for exchanging design and configuration data. Think of ARXML as the common language through which tools, teams, and organizations share automotive software architecture information.

Building a single vehicle involves numerous organizations — OEMs, Tier1 suppliers, Tier2 suppliers, and various tool vendors. Each uses different tools, yet they need to exchange design information consistently. ARXML provides that common format. The AUTOSAR consortium maintains dedicated serialization rules (AUTOSAR_TPS_ARXMLSerializationRules) that ensure consistent interpretation across different tools. An ARXML file created in one vendor's tool can be reliably imported into another, forming the backbone of multi-vendor collaboration.

Consider a practical example: a Tier1 supplier defines software component interfaces in ARXML and delivers them to the OEM. The OEM imports those ARXML files into their system integration tool and reflects them in the ECU configuration. No spreadsheets or Word documents needed — it is a standardized, machine-readable format.

What Does an ARXML File Contain?

ARXML files carry a surprisingly broad range of design and configuration information. Here are the main categories.

Software Architecture

The overall software structure is defined in ARXML: which Software Components (SWCs) exist, what ports they expose, and how components connect to each other. This defines the entire topology of the software system running on the vehicle.

ECU Configuration

Per-ECU settings are described in ARXML format, including which software is deployed to each ECU, how memory mapping is configured, and how OS tasks are set up. These configurations determine how the abstract software architecture maps to physical hardware.

Communication Protocols

Bus configurations for CAN, LIN, Ethernet, and other in-vehicle networks are defined here. This includes signal-to-PDU mappings, frame definitions, and routing configurations. The communication matrix that governs how ECUs exchange data is captured in ARXML.

Software Component Interfaces

This is the area engineers interact with most frequently in day-to-day work. It includes port definitions (Provide Ports and Require Ports), interface types (Sender-Receiver for data exchange, Client-Server for service calls), and data type definitions that specify the structure and constraints of exchanged data.

Runnable Specifications

Runnable entities within software components are specified with their execution periods, trigger events, and I/O data access patterns. These specifications define when and how often each piece of code executes within the AUTOSAR runtime environment.

State Management

Mode management and state transitions are captured in ARXML. For instance, an ECU's startup-run-shutdown state machine, diagnostic mode switching, or power mode transitions are all described through ARXML elements.

Classic Platform vs. Adaptive Platform

AUTOSAR has two platforms — Classic Platform (CP) and Adaptive Platform (AP). Both use ARXML, but the content and focus differ significantly.

Classic Platform ARXML is primarily static configuration. Everything is determined at compile time, which means ECU configurations, BSW (Basic Software) module settings, and RTE (Runtime Environment) configurations are described in exhaustive detail. Schema structures vary across releases like R4.4.0 and R4.3.1, so the specific release version matters when creating or editing these files.

Adaptive Platform ARXML reflects its service-oriented architecture (SOA). It covers service interface definitions, execution manifests, and network binding configurations. For example, defining a service interface on the Adaptive Platform requires specifying methods, events, and fields in a ServiceInterface element, then connecting it to SOME/IP binding configurations. Releases such as R20-11, R19-11, and R19-03 each support different feature scopes, so platform version compatibility is a key concern.

Why ARXML Editing is Challenging

Since ARXML is XML-based, you can technically open it in any text editor. But almost nobody does that in practice, and for good reason.

First, individual ARXML files frequently span thousands to tens of thousands of lines. Large projects manage hundreds of ARXML files simultaneously. Navigating this volume of structured XML by hand is impractical.

Second, the AUTOSAR schema is deeply nested and complex. XML namespaces, reference relationships between elements, and inheritance structures all need to be handled correctly. A single typo in a reference path can break the entire configuration.

Third, schemas differ across platform versions and releases. A structure that is valid in CP R4.4.0 may be invalid in R4.3.1. Engineers working across multiple projects or platform versions face constant context switching.

For these reasons, specialized editing tools are essential. Several widely-used commercial ARXML editors are available from established tool vendors.

Integration with Model-Based Design

ARXML does not exist in isolation. ARXML files can be imported into Simulink for Model-Based Design (MBD) workflows. Interface information defined in ARXML maps to Simulink model I/O ports, and code generated from Simulink models integrates back into the AUTOSAR framework.

This approach is particularly common in control algorithm development. Control logic is modeled and simulated in Simulink, while the software architecture, ECU configuration, and communication setup are managed in ARXML. Both sides must stay synchronized — the accuracy of ARXML directly affects the correctness of the entire system. When an interface definition in ARXML does not match the Simulink model, integration failures become inevitable.

Practical Challenges of ARXML Management

As projects grow in scope and complexity, ARXML management challenges multiply.

Version Control: ARXML files are text-based, so they can be managed with Git. However, different tools may generate XML tags in different orders. Even when no meaningful change has occurred, diffs can show massive differences simply due to tag reordering, making code review difficult.

Reference Integrity: When file A.arxml references an element in file B.arxml, modifying B can break the reference. As file counts grow, tracking these cross-file reference relationships manually becomes unmanageable.

Validation: Proper validation must cover schema compliance, reference integrity, and AUTOSAR semantic rules. Doing this manually across hundreds of files is virtually impossible.

Multi-Vendor Collaboration: When multiple vendors modify ARXML for the same system simultaneously, merge conflicts become frequent and resolution requires deep understanding of the architectural context.

Choosing the Right ARXML Tool

The efficiency of ARXML work depends heavily on tooling. When evaluating tools, several factors deserve attention.

Platform Support: Does the tool support only Classic Platform, or both CP and AP? Projects that span both platforms need a tool that handles both.

Release Compatibility: Confirm that the tool supports the specific AUTOSAR release versions your project uses.

Validation Capabilities: Schema-level validation is a baseline. The real differentiator is whether the tool also validates AUTOSAR semantic rules — catching logical errors, not just structural ones.

Accessibility: Whether a tool is installed locally or web-based affects team collaboration workflows. Web-based tools allow immediate access from any browser without installation, which can be a significant advantage for distributed teams.

AutoSAR.io: Web-Based ARXML Editor

PopcornSAR's AutoSAR.io is purpose-built for ARXML editing. It supports both Classic Platform (R4.4.0, R4.3.1) and Adaptive Platform (R20-11, R19-11, R19-03), offering two design modes tailored to different user needs.

Easy Design mode lets engineers define software components and interfaces through an intuitive UI without needing to understand the underlying ARXML schema complexity. Directive Design mode provides full schema-level control for detailed editing when precision is required. Built-in validation catches schema errors and reference issues in real time as you edit, preventing errors from propagating downstream.

Both installed and web-based versions are available, so teams can choose the deployment model that fits their project environment and security requirements.

Reducing ARXML Work with AI

The most time-consuming aspect of ARXML work is repetitive structure creation. Building dozens of similar software components, mapping signals to match a communication matrix, or configuring interface definitions one by one — these tasks consume significant engineering hours without requiring deep expertise.

PopcornSAR's AUTOSAR AI Agent automates these repetitive tasks using AI. Engineers can describe requirements in natural language and the agent generates the corresponding ARXML structures automatically. It also analyzes existing ARXML files to identify components and their relationships, and provides intelligent search across tags and configurations. Tasks that previously took 6 hours can be completed in 30 minutes, reducing development time by over 70%.

This is not about replacing the engineer's judgment — it is about eliminating the mechanical, repetitive portions of ARXML work so engineers can focus on architecture decisions and system design.

Summary

ARXML is the starting point and central axis of AUTOSAR development. From software architecture definitions to ECU configurations, communication protocols, and component interfaces, all design information flows through ARXML. How accurately you author ARXML and how efficiently you manage it directly determines your project's quality and delivery speed.

To improve your ARXML editing workflow, explore AutoSAR.io. For AI-powered automation of repetitive ARXML tasks, take a look at AUTOSAR AI Agent. If you have specific questions or want to discuss your project's needs, reach out through our contact page.

What is ARXML? — A Complete Guide to AUTOSAR's Configuration Language