> For the complete documentation index, see [llms.txt](https://docs.developers.symphony.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.developers.symphony.com/ext-apps.md).

# Extension Apps

- [Building Extension Apps](https://docs.developers.symphony.com/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](https://docs.developers.symphony.com/ext-apps/planning-your-app.md)
- [Getting Started](https://docs.developers.symphony.com/ext-apps/getting-started.md)
- [Getting Started with ADK](https://docs.developers.symphony.com/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](https://docs.developers.symphony.com/ext-apps/getting-started/bundle.md)
- [Add an Extension App to a Symphony Pod](https://docs.developers.symphony.com/ext-apps/getting-started/add-app-entry.md)
- [Overview of Extension API](https://docs.developers.symphony.com/ext-apps/overview-of-extension-api.md)
- [Initialization](https://docs.developers.symphony.com/ext-apps/overview-of-extension-api/initialization.md)
- [Register and Connect](https://docs.developers.symphony.com/ext-apps/overview-of-extension-api/register-and-connect.md)
- [Extension API Services](https://docs.developers.symphony.com/ext-apps/overview-of-extension-api/extension-api-services.md)
- [Service Interface](https://docs.developers.symphony.com/ext-apps/overview-of-extension-api/extension-api-services/service-interface.md)
- [Register and Subscribe](https://docs.developers.symphony.com/ext-apps/overview-of-extension-api/extension-api-services/register-and-subscribe.md)
- [Modules Service](https://docs.developers.symphony.com/ext-apps/overview-of-extension-api/extension-api-services/modules-service.md)
- [Entity Service](https://docs.developers.symphony.com/ext-apps/overview-of-extension-api/extension-api-services/entity-service.md)
- [Entity Advanced Templating](https://docs.developers.symphony.com/ext-apps/overview-of-extension-api/extension-api-services/entity-service/entity-advanced-templating.md)
- [Message Format - ExtensionML](https://docs.developers.symphony.com/ext-apps/overview-of-extension-api/extension-api-services/entity-service/message-format-extensionml.md)
- [Applications-Nav Service](https://docs.developers.symphony.com/ext-apps/overview-of-extension-api/extension-api-services/applications-nav-service.md)
- [Share Service](https://docs.developers.symphony.com/ext-apps/overview-of-extension-api/extension-api-services/share-service.md)
- [Commerce Service](https://docs.developers.symphony.com/ext-apps/overview-of-extension-api/extension-api-services/commerce-service.md)
- [Dialogs Service](https://docs.developers.symphony.com/ext-apps/overview-of-extension-api/extension-api-services/dialogs-service.md)
- [UI Service](https://docs.developers.symphony.com/ext-apps/overview-of-extension-api/extension-api-services/ui-service.md)
- [Receiving Conversation and User Information](https://docs.developers.symphony.com/ext-apps/overview-of-extension-api/extension-api-services/ui-service/receiving-conversation-and-user-information.md)
- [Filter Function](https://docs.developers.symphony.com/ext-apps/overview-of-extension-api/extension-api-services/ui-service/filter-function.md)
- [App Authentication](https://docs.developers.symphony.com/ext-apps/app-authentication.md)
- [Circle of Trust Authentication](https://docs.developers.symphony.com/ext-apps/app-authentication/circle-of-trust-authentication.md)
- [OBO Authentication](https://docs.developers.symphony.com/ext-apps/app-authentication/obo-authentication.md)


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.developers.symphony.com/ext-apps.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.