Otter Chrome DevTools

January 29, 2026 ยท View on GitHub

Otter Framework is providing an Otter Chrome Extension for your applications. The extension comes with the following features:

  • Application information: application version, environment, build date, etc.
  • Localization keys display
  • Visual Testing toggle
  • Rule Engine current state: rule engine state, rule engine logs, etc.
  • Configuration: display and modification of the application components configuration.
  • Theming: display and modification of the application theming variables.
  • States: save customization to be able to apply it later or share it.

How to install the extension

You can find the Otter Devtools Chrome extension by clicking on this link or by searching for Otter DevTools in the Chrome Web Store.

How to enable auto package registration

The Otter module will automatically register its Devtool service if the following configuration is set in the workspace configuration:

{
  "schematics": {
    "*:ng-add": {
      "registerDevtool": true
    }
  }
}

Note

This configuration is set by the --with-devtool option of the ng add @o3r/core command.

How to manually enable the extension support in your application

Once you have download the extension, you will need to enable the features you need one by one. There is no root toggle. To do so, you will need to import the corresponding modules in you AppModule:

import { ApplicationDevtoolsModule } from '@o3r/application';
import { ComponentsDevtoolsModule } from '@o3r/components';
import { ConfigurationDevtoolsModule } from '@o3r/configuration';
import { LocalizationDevtoolsModule } from '@o3r/localization';
import { RulesEngineDevtoolsModule } from '@o3r/rules-engine';
import { StylingDevtoolsModule } from '@o3r/styling';

@NgModule({
  imports: [
    ApplicationDevtoolsModule,
    ConfigurationDevtoolsModule,
    ComponentsDevtoolsModule,
    LocalizationDevtoolsModule,
    RulesEngineDevtoolsModule,
    StylingDevtoolsModule
  ]
})
export class AppModule {}

Then the activation of the services can be done in the App as follows:

import { ApplicationDevtoolsMessageService } from '@o3r/application';
import { ComponentsDevtoolsMessageService } from '@o3r/components';
import { ConfigurationDevtoolsMessageService } from '@o3r/configuration';
import { LocalizationDevtoolsMessageService } from '@o3r/localization';
import { RulesEngineDevtoolsMessageService } from '@o3r/rules-engine';
import { StylingDevtoolsMessageService } from '@o3r/styling';

@Component({
  selector: 'app'
})
export class App {
  constructor(
    applicationDevtoolsMessageService: ApplicationDevtoolsMessageService,
    componentsDevtoolsMessageService: ComponentsDevtoolsMessageService,
    configurationMessageService: ConfigurationDevtoolsMessageService,
    localizationMessageService: LocalizationDevtoolsMessageService,
    rulesEngineDevtoolsMessageService: RulesEngineDevtoolsMessageService,
    stylingDevtoolsMessageService: StylingDevtoolsMessageService
  ) {
    if (environment.DEBUG_MODE) {
      // It is strongly recommended to activate the Otter Devtools services only in the development mode
      applicationDevtoolsMessageService.activate();
      componentsDevtoolsMessageService.activate();
      configurationMessageService.activate();
      localizationMessageService.activate();
      rulesEngineDevtoolsMessageService.activate();
      stylingDevtoolsMessageService.activate();
    }
  }
}

Tip

The services can be also activated at bootstrap time by providing isActivatedOnBootstrap: true to their dedicated token OTTER_<module>_DEVTOOLS_OPTIONS. For example:

{provide: 'OTTER_CONFIGURATION_DEVTOOLS_OPTIONS', useValue: {isActivatedOnBootstrap: true}}

The services need to be injected in the application.

platformBrowserDynamic().bootstrapModule(AppModule).then((m) => runInInjectionContext(m.injector, () => inject(ConfigurationDevtoolsConsoleService)))

How to enable more features by providing metadata files

In your angular.json or project.json, you can specify assets in the options of @angular-devkit/build-angular:application.

"executor": "@angular-devkit/build-angular:application",
"options": {
  // ...,
  "assets": [
    // ...,
    {
      "glob": "**/*.metadata.json",
      "input": "apps/showcase",
      "output": "/metadata"
    }
  ]
},
// ...

Caution

We recommend adding this asset entry for the development configuration only.

Note

For the showcase application, we are exposing the metadata in production mode, in order to easily showcase the Chrome extension features.

How to test local modifications of the extension

If you are locally implementing modifications in the Otter DevTools extension, you can test these changes with the following steps:

  • Build the chrome-devtools application: yarn nx build chrome-devtools
  • Change the version from 0.0.0-placeholder to 0.0.0 in the files dist/package.json and dist/manifest.json
  • Go to the link chrome://extensions/ (enable Developer mode in the top-right corner), click the Load unpacked button, and select the dist folder of the previously built chrome-devtools application