> ## Documentation Index > Fetch the complete documentation index at: https://docs.support.onclarity.com/llms.txt > Use this file to discover all available pages before exploring further. # List outbound SIP trunks > Returns the project's outbound SIP trunks, oldest first. An outbound SIP trunk is the SIP endpoint of your carrier or PBX that Clarity dials through when an agent calls from one of your numbers. A trunk with username and password authentication shows `has_secret`; the password itself is never returned. ## OpenAPI ````yaml api-reference/voice-openapi.json GET /v1/projects/{projectId}/telephony/outbound-trunks openapi: 3.0.3 info: title: Clarity Voice API version: '1.0' description: >- Voice agents and their tools, outbound calls, conversations, campaigns, telephony, and evals. servers: - url: https://voice-api.onclarity.com security: - organizationApiKey: [] tags: - name: Projects description: >- The projects your organization owns. Every other resource lives in a project. - name: Agents description: Create, configure, version and publish voice agents. - name: Outbound calls description: Have a published agent phone a number now. - name: Conversations description: >- One record per call session, with its calls, recordings, transcripts and artifacts. - name: Calls description: The calls of a project, with their status, direction, timing and outcome. - name: Campaigns description: Outbound calling campaigns that phone a list of numbers on a schedule. - name: Eval suites description: >- Reusable sets of eval scenarios and test cases to measure an agent against. - name: Eval judges description: The LLM judges that score eval calls against your test cases. - name: Eval scenarios description: The simulated-caller scenarios of your eval suites. - name: Eval test cases description: The checks a judge applies to each eval call. - name: Eval submissions description: Run an eval suite against an agent and read the verdicts. - name: Phone numbers description: >- The phone numbers of a project, where their calls come from, and how agents call out from them. - name: Inbound SIP trunks description: Bring calls from your own SIP infrastructure to Clarity agents. - name: Outbound SIP trunks description: >- The SIP endpoints Clarity dials through for outbound calls from your numbers. - name: Tools description: The tools agents call during a conversation, and which agents use them. paths: /v1/projects/{projectId}/telephony/outbound-trunks: parameters: - $ref: '#/components/parameters/ProjectIdPath' get: tags: - Outbound SIP trunks summary: List outbound SIP trunks description: >- Returns the project's outbound SIP trunks, oldest first. An outbound SIP trunk is the SIP endpoint of your carrier or PBX that Clarity dials through when an agent calls from one of your numbers. A trunk with username and password authentication shows `has_secret`; the password itself is never returned. operationId: listTelephonyOutboundTrunks responses: '200': description: The project's outbound SIP trunks. content: application/json: schema: $ref: '#/components/schemas/OutboundTrunksListResponse' example: outbound_trunks: - id: 9a8b7c6d-5e4f-4a3b-8c2d-1e0f9a8b7c6d project_id: 3f6c1a52-8d0e-4b8f-9a51-2c7d4e0b9f13 name: Carrier primary address: sip.carrier.example.com auth: type: basic username: clarity-outbound has_secret: true status: active transport: tls media_encryption: enabled created_at: >- Mon Nov 09 2026 13:58:20 GMT+0000 (Coordinated Universal Time) updated_at: >- Mon Nov 09 2026 13:58:20 GMT+0000 (Coordinated Universal Time) '401': $ref: '#/components/responses/Unauthorized' '404': description: The project does not exist or your key cannot reach it. content: application/json: schema: $ref: '#/components/schemas/Error' components: parameters: ProjectIdPath: name: projectId in: path required: true schema: type: string description: Project id schemas: OutboundTrunksListResponse: type: object required: - outbound_trunks properties: outbound_trunks: type: array items: $ref: '#/components/schemas/OutboundTrunk' Error: type: object required: - error additionalProperties: true properties: error: type: string description: Error message code: type: string description: >- A stable machine-readable reason, present on the refusals a client may branch on. Among them: `PUBLISH_CAPABILITY_REQUIRED` (403, the credential may not change what is live), `AGENT_NOT_PUBLISHED` (409, the agent has no published version yet), `AGENT_TYPE_NOT_DISPATCHABLE` (422, a Voice Assist agent named where an agent must place a call or answer one itself — a campaign, an outbound caller ID, a dispatched call, an eval; a number's inbound dispatch rule accepts one; the body carries `agent_type` and `agent_id`), `ASSIST_FLEET_NOT_CONFIGURED` (422 on a dispatch rule naming a Voice Assist agent in a project whose LiveKit has no Voice Assist listener), `NOT_APPLICABLE_TO_AGENT_TYPE` (422, a voice-only setting written on a Voice Assist agent), `AGENT_TYPE_BOUNDARY` (409), `AGENT_TYPE_NOT_SUPPORTED` (400), `INVALID_CUSTOMER_TIMEZONE` (400, `customer_timezone` is not a time zone name; the body carries the value), `VOICE_ASSISTANT_REQUIRED` (403, the organization is not licensed for Voice Assist), `ORGANIZATION_UNAVAILABLE` (503), `REGION_PROFILE_CONFLICT` (503), `LLM_SERVICE_TIER_UNAVAILABLE` (422, an agent's processing speed is not offered by its model or not enabled for the organization; `reason` says which) and `AUTH_UPSTREAM_UNAVAILABLE` (503 on any endpoint, with `Retry-After`: the credential could not be checked right now; it was not rejected and the request was not carried out). OutboundTrunk: type: object description: >- A SIP endpoint Clarity dials through for outbound calls from your numbers. required: - id - project_id - name - address - auth - status - transport - media_encryption - created_at - updated_at properties: id: type: string description: Outbound SIP trunk id. project_id: type: string name: type: string description: Unique within the project. address: type: string description: >- The SIP host Clarity sends calls to, such as `sip.carrier.example.com`. auth: $ref: '#/components/schemas/OutboundTrunkAuth' status: type: string enum: - active - inactive description: >- An `inactive` trunk is not used for calls and cannot be assigned to a number. transport: type: string enum: - auto - udp - tcp - tls description: SIP transport. `auto` negotiates it. media_encryption: type: string enum: - disabled - enabled - required description: >- Media encryption (SRTP). `enabled` offers it and falls back to plain media; `required` refuses calls without it. created_at: type: string description: >- When the trunk was created. A date string such as `Mon Nov 09 2026 13:58:20 GMT+0000 (Coordinated Universal Time)`, not ISO 8601. updated_at: type: string description: When the trunk was last changed. A date string, as `created_at`. OutboundTrunkAuth: type: object required: - type description: >- How Clarity authenticates to the trunk. The password is write-only: responses never contain it and show `has_secret` instead. properties: type: type: string enum: - none - basic description: >- `none`: no authentication. `basic`: SIP digest authentication with a username and password. username: type: string description: The username. Present for `basic`. has_secret: type: boolean description: Present for `basic`. Whether a password is stored. responses: Unauthorized: description: >- No credential was sent, or the API key is invalid or revoked. A key that could not be checked at all answers 503 `AUTH_UPSTREAM_UNAVAILABLE` instead (see Errors). content: application/json: schema: $ref: '#/components/schemas/Error' example: error: Invalid or revoked token securitySchemes: organizationApiKey: type: http scheme: bearer description: >- Your organization API key (it starts with `anek_org_`). The same key works on the Voice API and the Support API. See [Authentication](/authentication). ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.