schema.json

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://stac-extensions.github.io/template/v1.0.0/schema.json#",
  "title": "Template Extension",
  "description": "STAC Template Extension for STAC Items and STAC Collections.",
  "oneOf": [
    {
      "$comment": "This is the schema for STAC Items. Remove this object if this extension only applies to Collections.",
      "allOf": [
        {
          "type": "object",
          "required": [
            "type",
            "properties",
            "assets"
          ],
          "properties": {
            "type": {
              "const": "Feature"
            },
            "properties": {
              "allOf": [
                {
                  "$comment": "Require fields here for item properties.",
                  "required": [
                    "template:new_field"
                  ]
                },
                {
                  "$ref": "#/definitions/fields"
                }
              ]
            },
            "assets": {
              "type": "object",
              "additionalProperties": {
                "$ref": "#/definitions/fields"
              }
            }
          }
        },
        {
          "$ref": "#/definitions/stac_extensions"
        }
      ]
    },
    {
      "$comment": "This is the schema for STAC Collections. Remove this object if this extension does not define top-level fields for Collections AND can't be used in collection assets or item asset defintions.",
      "allOf": [
        {
          "type": "object",
          "required": [
            "type"
          ],
          "properties": {
            "type": {
              "const": "Collection"
            },
            "assets": {
              "type": "object",
              "additionalProperties": {
                "$ref": "#/definitions/fields"
              }
            },
            "item_assets": {
              "type": "object",
              "additionalProperties": {
                "$ref": "#/definitions/fields"
              }
            }
          }
        },
        {
          "$ref": "#/definitions/stac_extensions"
        },
        {
          "$comment": "Remove this object if this extension does not define top-level fields for Collections.",
          "$ref": "#/definitions/fields"
        }
      ]
    }
  ],
  "definitions": {
    "stac_extensions": {
      "type": "object",
      "required": [
        "stac_extensions"
      ],
      "properties": {
        "stac_extensions": {
          "type": "array",
          "contains": {
            "const": "https://stac-extensions.github.io/template/v1.0.0/schema.json"
          }
        }
      }
    },
    "fields": {
      "$comment": "Add your new fields here. Don't require them here, do that above in the item schema.",
      "type": "object",
      "properties": {
        "template:new_field": {
          "type": "string"
        },
        "template:xyz": {
          "type": "object",
          "required": [
            "x",
            "y",
            "z"
          ],
          "properties": {
            "x": {
              "type": "number"
            },
            "y": {
              "type": "number"
            },
            "z": {
              "type": "number"
            }
          }
        }, 
        "template:another_one": {
          "type": "array", 
          "items": {
            "type": "number"
          }
        }
      },
      "patternProperties": {
        "^(?!template:)": {
          "$comment": "Above, change `template` to the prefix of this extension"
        }
      },
      "additionalProperties": false
    }
  }
}