FluentAAS – Fluent C# Library for the Asset Administration Shell

Building AAS models in C# shouldn't require reading 500 pages of specs first.

FluentAAS gives you a fluent API that feels like writing normal C# code – while handling the complexity of AAS 3.0 compliance under the hood.

var environment = AasBuilder.Create()
    .AddShell("urn:aas:my-machine", "CNC-Machine-2000")
    .WithGlobalAssetId("urn:asset:serial-001")
    .AddDigitalNameplate("urn:submodel:nameplate")
        .WithManufacturerName("en", "Acme Manufacturing Ltd.")
        .WithSerialNumber("SN-2024-00142")
        .BuildDigitalNameplate()
    .CompleteShellConfiguration()
    .Build();

That's it. A valid, IDTA-compliant AAS model. Ready to export.

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The Problem

If you've ever tried to create AAS models programmatically, you know the pain:

• The IDTA specs are hundreds of pages long
• Most tooling is Java-based (Eclipse BaSyx, AASX Package Explorer)
• Building JSON/XML structures by hand is error-prone
• Semantic IDs are easy to get wrong – and you won't know until import fails

I built FluentAAS because I needed something that just works for .NET developers. No ceremony, no boilerplate, no guessing if your model is valid.

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What FluentAAS Does

Fluent Builder API
Create shells, submodels, and elements using a clean, chainable syntax. IntelliSense guides you through the API.

Supported Submodel Templates
Pre-built builders for official IDTA templates (Digital Nameplate, more coming). They enforce required fields and set semantic IDs automatically.

Immutable Model
All AAS types are C# records. Great for testing, snapshots, and debugging.

Validation
Catch problems before export. The validation service gives you detailed error reports.

JSON & AASX Export
Serialize to JSON or package as AASX for import into other tools.

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Getting Started

dotnet add package FluentAAS.Builder

Basic Example

using FluentAAS;

// Create an AAS environment
var environment = AasBuilder.Create()
    .AddShell("urn:aas:example:cnc-machine", "CNC-Mill-2000")
    .WithGlobalAssetId("urn:asset:example:cnc-001")
    
    // Add a Digital Nameplate (IDTA 02006-2-0)
    .AddDigitalNameplate("urn:submodel:example:nameplate")
        .WithManufacturerName("en", "Acme Manufacturing Ltd.")
        .WithManufacturerName("de", "Acme Maschinenbau GmbH")
        .WithManufacturerProductDesignation("en", "Universal CNC Milling Machine")
        .WithSerialNumber("SN-2024-00142")
        .WithYearOfConstruction("2024")
        .BuildDigitalNameplate()
    .CompleteShellConfiguration()
    .Build();

// Export as JSON
string json = AasJsonSerializer.ToJson(environment);

// Or as AASX package
environment.ToAasx("./cnc-machine.aasx");

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Two Ways to Build Submodels

1. Supported Templates (Recommended)

Use these when your submodel matches an official IDTA template. The builder enforces required fields and sets the correct semantic IDs.

.AddDigitalNameplate("urn:submodel:nameplate")
    .WithManufacturerName("en", "Acme Ltd.")    // required
    .WithSerialNumber("SN-001")                  // required
    .WithContactInformation(contact => contact
        .WithPhone("+49 123 456789")
        .WithEmail("info@acme.example"))
    .BuildDigitalNameplate()

Currently supported:

• Digital Nameplate V2.0 (IDTA 02006-2-0)

Planned:

• Handover Documentation
• Technical Data
• Digital Product Passport

2. Generic Builder

For custom submodels or templates not yet supported:

.AddSubmodel("urn:submodel:custom", "ProductionData")
    .WithSemanticId(new Reference(
        ReferenceTypes.ExternalReference,
        [new Key(KeyTypes.Submodel, "urn:my-company:production-data:1.0")]))
    .AddProperty("Temperature", "85.5")
    .AddProperty("SpindleSpeed", "1200")
    .AddMultiLanguageProperty("Status", ls => ls
        .Add("en", "Running")
        .Add("de", "Läuft"))
    .CompleteSubmodelConfiguration()

You get full control when you need it.

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Project Structure

Package	What it does
FluentAAS.Core	Immutable AAS meta-model types (C# records)
FluentAAS.Builder	Fluent builders + submodel templates
FluentAAS.Validation	Rule-based validation against AAS 3.0
FluentAAS.IO	JSON serialization, AASX packaging

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Validation

var validator = new AasValidationService();
var report = validator.Validate(environment);

if (!report.IsValid)
{
    foreach (var error in report.Errors)
    {
        Console.WriteLine($"{error.Path}: {error.Message}");
    }
}

Find issues before your customer does.

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Why I Built This

I worked on AAS tooling at Fraunhofer IOSB-INA. The official specs are thorough – but not exactly developer-friendly. Most examples are in Java. The XML/JSON structures are verbose. And when something doesn't work, the error messages rarely help.

FluentAAS is my attempt to make AAS practical for .NET teams. Not a complete replacement for the official tools – but a library that handles the common cases well.

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What This Is (and Isn't)

FluentAAS is:

• A library for creating AAS models in C#
• Focused on developer experience
• Good for generating Digital Nameplates and similar submodels
• MIT licensed, use it however you want

FluentAAS is not:

• A full AAS server implementation
• A replacement for AASX Package Explorer
• Feature-complete (yet)

I'm building this in the open. If a template you need is missing, let me know – or submit a PR.

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Roadmap

Feature	Status
Digital Nameplate V2.0	✅ Done
JSON/AASX Export	✅ Done
Validation Service	✅ Done
Handover Documentation	✅ Done
Technical Data	📋 Planned
Digital Product Passport	📋 Planned
AAS Registry Integration	📋 Planned

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Contributing

PRs welcome for:

• New IDTA submodel templates
• Better validation rules
• Documentation and examples
• Bug fixes

If you're unsure whether something fits, open an issue first.

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Resources

• IDTA Submodel Templates – Official template specs
• AASX Package Explorer – GUI tool for viewing/editing AAS
• AAS Specs – The full specification

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License

MIT – free for commercial and open-source use.

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Questions?

If you're working on AAS integration and have questions, feel free to reach out on LinkedIn.

I'm also available for consulting on .NET modernization and Industry 4.0 projects – but no pressure. The library stands on its own.