Choosing Between Forge and FHIR Shorthand (FSH): A Strategic Guide for Modeling FHIR Profiles

When modeling FHIR resources, you have two powerful tools at your disposal: Forge and FHIR Shorthand (FSH). Each has distinct strengths that cater to different modeling preferences and workflows. Let’s explore how these tools can serve your FHIR modeling needs.

What are we comparing?

At their core, both tools help you create FHIR resources, just in different ways:

• Forge is a graphical user interface (GUI) for creating and editing FHIR resources
• FHIR Shorthand (FSH) is a domain-specific language for defining FHIR resources through code

Both tools ultimately produce the same output: standard FHIR resources in JSON (or XML) format, which form the foundation of any FHIR specification.

Understanding Forge

Forge excels in these areas:

👉 Graphical Editing: A visual interface that shows all available options and guides you through best practices

👉 Resource Support: Specialized in key resources like StructureDefinitions (Profiles, Extensions, Logical Models), OperationDefinitions, and SearchParameters

👉 Accessibility: Ideal for clinical modelers and domain experts who prefer visual modeling

👉 Platform: Windows-native, but works well through VMs on Mac/Linux

👉 Integration: Direct synchronization with Simplifier

The visual nature of Forge means you can see the complete structure of what you’re working with, making it particularly effective for understanding and applying FHIR concepts.

Understanding FSH

FHIR Shorthand offers different advantages:

👉 Code-Based Editing: Perfect for those with programming background who prefer text-based editing

👉 Comprehensive Support: Works with all FHIR resource types

👉 Development Environment: Local editing with VS Code + FHIR Shorthand extensions

👉 Tooling: Conversion through SUSHI, with options for local or online editing

👉 Flexibility: Great for both small and large-scale projects

FSH starts with a blank canvas, requiring some knowledge of what you want to model and familiarity with the language. However, it offers powerful capabilities for those who prefer code-based editing.

Working Environment Options

Both tools are, right now, primarily desktop applications that can integrate with online platforms:

Desktop Development

• Forge: Run as a native Windows application (or via VM for Mac/Linux)
• FSH: Edit with VS Code + FHIR Shorthand extensions, convert using SUSHI

Cloud Integration

• Forge: Direct synchronization with Simplifier
• FSH: Upload JSON results to Simplifier using tools like Firely Terminal

Speaking of cloud: Soon we will add to these options FSH editing in the fully integrated online Resource Editor in Simplifier! For FHIR Shorthand there are already some limited online development environments available, like Simplifier’s FSH Playground and FSH Online.

But with this new studio, we get around two of the biggest problems with FHIR Shorthand and bring FSH development closer to the visual Forge experience:

• Direct validation feedback and visualization on every keystroke, so starting with a blank file is not as daunting anymore
• No installation needed, which can be a life saver for those with closed-down laptops or limited command line experience

Combining Forge and FSH

Many teams effectively leverage the strengths of both tools in their workflow.

They use Forge for resources where it excels:

• StructureDefinitions (Profiles, Extensions, Logical Models)
• OperationDefinitions
• SearchParameters

💡 Tip: In Forge, make sure to turn on the setting to save resources with a snapshot component, since FSH requires this.

They use FSH for:

• Example data
• Terminology (ValueSets, CodeSystems)
• Other resource types

This combined approach allows teams to leverage the visual modeling benefits of Forge while taking advantage of FSH’s flexibility for other resources.

Making Your Choice

Consider these factors when choosing:

1. Modeling Preference: Do you prefer visual modeling or code-based editing?

2. Team Background: What’s your team’s technical comfort level?

3. Resource Types: Which FHIR resources are you primarily working with?

4. Development Environment: What’s your preferred working environment?

Final Thoughts

Remember, your choice of modeling tool is independent of how you create and publish your implementation guides. Whether you use Forge or FSH, the end result is standard FHIR resources that can be used with any FHIR tooling, including Simplifier’s Implementation Guide editor.

Choose the tool that matches your team’s modeling preferences and workflow needs. Both are valid approaches that can produce high-quality FHIR artifacts. The key is selecting the one that best supports your team’s way of working.

Happy modeling!