Extensions Overview

Fairspec Dataset has a simple yet powerful extension mechanism based on JSON Schema. Extensions allow you to create domain-specific profiles that add custom properties and validation rules while maintaining compatibility with the base specification.

Tip

Use the Fairspec Extension repository template for rapid extensions development.

How Extensions Work

An extension is a JSON Schema that:

1. References the base Fairspec Dataset schema in an allOf property
2. Adds domain-specific properties and constraints
3. Can be referenced via the $schema property in dataset descriptors

Using JSON Schema features, extensions can:

• Add new custom properties for domain-specific metadata
• Require specific properties or values
• Define expected resource types and their schemas
• Enforce validation rules unique to your domain
• Combine multiple profiles into higher-level extensions

Extensions are ideal for:

• Scientific domains with specialized metadata (spectroscopy, genomics, imaging)
• Organizations with internal data standards
• Research communities with shared conventions
• Compliance with domain-specific requirements

See the Dataset Specification for complete technical details.

Example: Spectroscopy Extension

A dataset using a custom spectroscopy profile:

{
  "$schema": "https://spectroscopy.org/profiels/1.0.0/dataset.json",
  "title": "Infrared Spectroscopy Data",
  "resources": [
    {
      "data": "spectrum.csv",
      "spectralRange": {
        "min": 400,
        "max": 4000,
        "unit": "cm-1"
      }
    }
  ]
}

The extension schema that enables this:

{
  "$schema": "http://json-schema.org/draft/2020-12/schema",
  "title": "Fairspec Spectroscopy Profile",
  "allOf": [
    { "$ref": "https://fairspec.org/profiles/1.0.0/dataset.json" },
    { "$ref": "#/$defs/spectroscopyMixin" }
  ],
  "$defs": {
    "spectroscopyMixin": {
      "type": "object",
      "properties": {
        "resources": {
          "type": "array",
          "items": {
            "properties": {
              "spectralRange": {
                "type": "object",
                "required": ["min", "max", "unit"],
                "properties": {
                  "min": { "type": "number" },
                  "max": { "type": "number" },
                  "unit": { "type": "string" }
                }
              }
            }
          }
        }
      }
    }
  }
}