API Extension Designer
The API Extension Designer is a visual tool for creating API extension packages (.pkg files). Extensions add typed request/response support, auto-completion, and documentation to Aethrix Studio.
What It Does
An API extension is a compiled package that contains:
- Typed .NET classes (DTOs) — generated from API schemas for request and response models
- Operation metadata — URL templates, HTTP methods, SOAP actions, GraphQL operations
- Service definitions — organized by application and service
When installed, extensions populate the service tree and enable the typed object editor for the API's operations.
When to Use It
Use the API Extension Designer when you need to:
- Share a typed, auto-completing client for an internal or third-party API across your team.
- Package SOAP, REST/OpenAPI, OData, Kafka, GraphQL, gRPC, or WebSocket services so others can install them from the Extension Repository.
- Maintain versioned API definitions — with changelog, tags, and release notes — instead of ad-hoc spec files.
How to Use It
The designer has three main areas:
| Zone | Purpose |
|---|---|
| Toolbar | New, Open, Close, Save, Save as..., Analyze, Build, Publish to Repository, Re-analyze, Add Application, Add Service, Delete |
| Project Tree | Hierarchical view of applications and services |
| Detail Panel | Context-sensitive editor for the selected tree node |
Screenshot: API Extension Designer with project tree and detail panel.
Supported Source Formats
A service is defined by its Service Type (set in the Service Panel) and, for imported specs, a Definition URI:
| Service Type | Spec source |
|---|---|
| OpenAPI | .json, .yaml, or URL |
| WSDL | .wsdl file or URL |
| CSDL (OData) | CSDL / EDMX metadata |
| Kafka Schema Registry | Confluent-compatible Schema Registry URL |
| GraphQL | SDL file or introspection endpoint |
| gRPC (Protobuf) | .proto file |
| WebSocket (AsyncAPI) | AsyncAPI 3.0 document |
| Designer (API Designer) | Defined in-place with the built-in designer |
| Manual | No spec — describe operations yourself |
The onboarding screen shows format badges for WSDL, OpenAPI, Kafka, GraphQL, and Manual.
Typical Workflow
Onboarding
When no project is open, the designer shows:
- A hero with + New project and Open buttons
- Format badges (WSDL, OpenAPI, Kafka, GraphQL, Manual)
- A 3-step guide: Create a project → Add applications & services → Build & publish
- A Recent projects list