> ## Documentation Index > Fetch the complete documentation index at: https://docs.vobiz.ai/llms.txt > Use this file to discover all available pages before exploring further. # The Application Object > Explore every field of the Vobiz Application object - answer_url, hangup_url, message_url, HTTP methods, SIP URI, and fallback behavior for call routing. An Application is a named container for the webhook URLs that control your call flow. You attach a phone number or a SIP endpoint to an application so that calls fire its configured webhooks. See [Application vs Endpoint](#application-vs-endpoint) below to choose the right object. ## Attributes | Field | Type | Description | | ---------------------- | ----------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `app_id` | string | Unique identifier for the application. Use it in all per-application API paths. | | `app_name` | string | Name of the application. | | `answer_url` | string | URL Vobiz fetches when a call executes this application. Must return valid VobizXML to control the call flow. | | `answer_method` | string | HTTP method for `answer_url`. One of `GET` or `POST`. Default `POST`. | | `hangup_url` | string | URL notified when the call ends. Useful for analytics and cleanup. If unset at create time, defaults to `answer_url`. | | `hangup_method` | string | HTTP method for `hangup_url`. One of `GET` or `POST`. Default `POST`. | | `fallback_answer_url` | string (nullable) | Backup URL invoked only when `answer_url` is unreachable, times out, or returns invalid VobizXML. Must itself return valid VobizXML. `null` when unset. | | `fallback_method` | string | HTTP method for `fallback_answer_url`. One of `GET` or `POST`. Default `POST`. | | `message_url` | string (nullable) | URL notified when an inbound message is received. Vobiz expects an HTTP 200 response. `null` when unset. | | `message_method` | string | HTTP method for `message_url`. One of `GET` or `POST`. Default `POST`. | | `default_number_app` | boolean | If `true`, newly created numbers without an `app_id` are auto-routed to this application. Default `false`. Does not retroactively re-route existing numbers. | | `default_endpoint_app` | boolean | If `true`, newly created endpoints without an `application` are auto-routed to this application. Default `false`. Does not retroactively re-route existing endpoints. | | `sub_account` | string (nullable) | Sub-account `auth_id`. `null` for the main account. Cannot be changed after creation. | | `resource_uri` | string | API resource URI for this application. | | `application_type` | string | Type of application. Typically `XML` (also seen as `voice`). | | `default_app` | boolean | Whether this is the account-level default application. Default `false`. | | `enabled` | boolean | Whether the application is enabled. Default `true`. | | `log_incoming_message` | boolean | Whether incoming messages to numbers on this application are logged. Default `true`. | | `public_uri` | boolean | Whether the application's `sip_uri` is reachable by external SIP systems. Default `false`. See [Public SIP URI](#public-sip-uri). | | `sip_transfer_method` | string | HTTP method for SIP transfer callbacks. One of `GET` or `POST`. | | `sip_transfer_url` | string (nullable) | URL notified during a SIP transfer. `null` when unset. | | `sip_uri` | string | SIP URI associated with the application, e.g. `sip:@sip.vobiz.ai`. | | `created_at` | string (ISO 8601) | Creation timestamp (UTC). | | `updated_at` | string (ISO 8601) | Last update timestamp (UTC). | `api_id` is a request-correlation ID returned alongside the object on single-object responses (Create, Retrieve, Update). It is not a persistent attribute of the application. ## Example Application Object ```json JSON theme={null} { "answer_method": "POST", "answer_url": "https://example.com/answer", "api_id": "aabbccdd-1234-5678-90ab-cdef12345678", "app_id": "12345678901234567", "app_name": "My Voice App", "application_type": "XML", "created_at": "2026-04-02 12:11:19.740666+00:00", "default_app": false, "default_endpoint_app": false, "enabled": true, "fallback_answer_url": null, "fallback_method": "POST", "hangup_method": "POST", "hangup_url": "https://example.com/hangup", "log_incoming_message": true, "message_method": "POST", "message_url": null, "public_uri": false, "resource_uri": "/v1/Account/MA_XXXXXXXX/Application/12345678901234567/", "sip_transfer_method": "POST", "sip_transfer_url": null, "sip_uri": "sip:12345678901234567@app.vobiz.ai", "sub_account": null, "updated_at": "2026-04-02 12:11:19.740666+00:00" } ``` ## Application vs Endpoint | You want to... | Use | | --------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------- | | Route inbound calls on a **phone number (DID)** to your webhooks | An **Application**, then [attach the number](/applications/attach-number) to it. | | Let a **device or person** (browser, softphone, desk phone, AI agent) place and receive calls | An [**Endpoint**](/endpoint/endpoint-object), with an Application attached for its call logic. | | Both - a number rings, then routes to a device | A number attached to an Application whose VobizXML `Dial`s the endpoint's `sip_uri`. | ## Public SIP URI Every application has a `sip_uri` such as `sip:@sip.vobiz.ai`. By default `public_uri` is `false`, meaning the URI is not exposed to external SIP systems. Set `public_uri: true` only when a third-party SIP system - for example another PBX or carrier - needs to route calls **directly** into this application's `sip_uri`. For ordinary inbound flows driven by a Vobiz phone number, leave `public_uri` as `false`.