JSON resources in extensions

​

JSON capabilities

​

JSON support

​

Sample JSON declaration in manifest.json

{
  "manifest_version": 3,
  "name": "My Extension",
  "version": "1.0.0",
  "declarative_net_request": {
    "rule_resources": [
      {
        "id": "ruleset_1",
        "enabled": true,
        "path": "rules/ruleset.json"
      }
    ]
  },
  "storage": {
    "managed_schema": "schema/storage-schema.json"
  }
}

​

Output path

declarative_net_request/<ruleset-id>.json
storage/managed_schema.json

​

Development behavior

• Extension.js tracks manifest-referenced JSON files as file dependencies.
• JSON edits trigger recompilation.
• Some structural manifest changes related to JSON may require a dev server restart.

​

Validation behavior

• JSON syntax for referenced resources
• DNR ruleset shape (array-based ruleset expectations)
• Managed storage schema shape (object-based expectations)

​

Environment placeholders

​

Best practices

• Keep manifest-referenced JSON focused on browser-required resource formats.
• Validate JSON resources in continuous integration (CI) before packaging.
• Prefer stable file paths in manifest to reduce restart-required structural changes in development.
• For app data consumed by code, consider JSON imports in JS/TS modules separately from manifest resource JSON.

​

Next steps

• Continue with icons in development.
• Learn about manifest development behavior.