# Extension Apps

- [Building Extension Apps](/ext-apps/building-extension-apps.md): Building Extension Apps on Symphony Messaging is an easy and secure way to customize the Symphony Messaging experience. Take these simple steps in order to create and deploy your Extension App today!
- [Planning Your App](/ext-apps/planning-your-app.md)
- [Getting Started](/ext-apps/getting-started.md)
- [Getting Started with ADK](/ext-apps/getting-started/adk.md): The App Developer Kit (ADK) is the preferred tooling for web developers to get started building extension apps on Symphony
- [Application Manifest Bundle](/ext-apps/getting-started/bundle.md)
- [Add an Extension App to a Symphony Pod](/ext-apps/getting-started/add-app-entry.md)
- [Overview of Extension API](/ext-apps/overview-of-extension-api.md)
- [Initialization](/ext-apps/overview-of-extension-api/initialization.md)
- [Register and Connect](/ext-apps/overview-of-extension-api/register-and-connect.md)
- [Extension API Services](/ext-apps/overview-of-extension-api/extension-api-services.md)
- [Service Interface](/ext-apps/overview-of-extension-api/extension-api-services/service-interface.md)
- [Register and Subscribe](/ext-apps/overview-of-extension-api/extension-api-services/register-and-subscribe.md)
- [Modules Service](/ext-apps/overview-of-extension-api/extension-api-services/modules-service.md)
- [Entity Service](/ext-apps/overview-of-extension-api/extension-api-services/entity-service.md)
- [Entity Advanced Templating](/ext-apps/overview-of-extension-api/extension-api-services/entity-service/entity-advanced-templating.md)
- [Message Format - ExtensionML](/ext-apps/overview-of-extension-api/extension-api-services/entity-service/message-format-extensionml.md)
- [Applications-Nav Service](/ext-apps/overview-of-extension-api/extension-api-services/applications-nav-service.md)
- [Share Service](/ext-apps/overview-of-extension-api/extension-api-services/share-service.md)
- [Commerce Service](/ext-apps/overview-of-extension-api/extension-api-services/commerce-service.md)
- [Dialogs Service](/ext-apps/overview-of-extension-api/extension-api-services/dialogs-service.md)
- [UI Service](/ext-apps/overview-of-extension-api/extension-api-services/ui-service.md)
- [Receiving Conversation and User Information](/ext-apps/overview-of-extension-api/extension-api-services/ui-service/receiving-conversation-and-user-information.md)
- [Filter Function](/ext-apps/overview-of-extension-api/extension-api-services/ui-service/filter-function.md)
- [App Authentication](/ext-apps/app-authentication.md)
- [Circle of Trust Authentication](/ext-apps/app-authentication/circle-of-trust-authentication.md)
- [OBO Authentication](/ext-apps/app-authentication/obo-authentication.md)