> ## 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. # Create an outbound SIP trunk > Adds a SIP endpoint to dial out through. Assign it to a phone number with `outbound_trunk_ids` to use it. With `auth.type: basic`, send the username and `password`; the password is write-only, and responses show `has_secret` instead. Needs the publish permission, which organization API keys carry. ## OpenAPI ````yaml api-reference/voice-openapi.json POST /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' post: tags: - Outbound SIP trunks summary: Create an outbound SIP trunk description: >- Adds a SIP endpoint to dial out through. Assign it to a phone number with `outbound_trunk_ids` to use it. With `auth.type: basic`, send the username and `password`; the password is write-only, and responses show `has_secret` instead. Needs the publish permission, which organization API keys carry. operationId: createTelephonyOutboundTrunk requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/CreateOutboundTrunkRequest' example: name: Carrier primary address: sip.carrier.example.com auth: type: basic username: clarity-outbound password: example-password-not-real transport: tls media_encryption: enabled responses: '201': description: The trunk was created. content: application/json: schema: $ref: '#/components/schemas/OutboundTrunkResponse' example: outbound_trunk: 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' '403': description: >- Your credential lacks the publish permission (`code: PUBLISH_CAPABILITY_REQUIRED`). content: application/json: schema: $ref: '#/components/schemas/Error' example: error: publish_capability_required code: PUBLISH_CAPABILITY_REQUIRED '404': description: The project does not exist or your key cannot reach it. content: application/json: schema: $ref: '#/components/schemas/Error' '409': description: Another outbound SIP trunk in the project has this name. content: application/json: schema: $ref: '#/components/schemas/Error' example: error: Outbound trunk "Carrier primary" already exists '422': $ref: '#/components/responses/ValidationFailed' components: parameters: ProjectIdPath: name: projectId in: path required: true schema: type: string description: Project id schemas: CreateOutboundTrunkRequest: type: object required: - name - address - auth description: Fields not listed here are ignored. properties: name: type: string minLength: 1 maxLength: 128 description: Unique within the project. address: type: string minLength: 1 maxLength: 255 description: The SIP host to send calls to, such as `sip.carrier.example.com`. auth: oneOf: - $ref: '#/components/schemas/OutboundTrunkAuthNone' - $ref: '#/components/schemas/OutboundTrunkAuthBasicCreate' discriminator: propertyName: type mapping: none: '#/components/schemas/OutboundTrunkAuthNone' basic: '#/components/schemas/OutboundTrunkAuthBasicCreate' status: type: string enum: - active - inactive default: active transport: type: string enum: - auto - udp - tcp - tls default: auto description: SIP transport. `auto` negotiates it. media_encryption: type: string enum: - disabled - enabled - required default: disabled description: >- Media encryption (SRTP). `enabled` offers it with a fallback; `required` refuses calls without it. OutboundTrunkResponse: type: object required: - outbound_trunk properties: outbound_trunk: $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). OutboundTrunkAuthNone: type: object required: - type description: No authentication. properties: type: type: string enum: - none OutboundTrunkAuthBasicCreate: type: object required: - type - username - password description: SIP digest authentication. properties: type: type: string enum: - basic username: type: string minLength: 1 password: type: string minLength: 1 writeOnly: true description: Write-only. Never returned; responses show `has_secret`. 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`. ValidationError: type: object description: >- A validation failure. `error` is a human-readable summary; `issues` (request validation) or `details` (agent configuration validation) locate each problem. A refused processing speed answers with `error` and `code` both `LLM_SERVICE_TIER_UNAVAILABLE` and the fields `path`, `reason`, `tier`, `provider` and `model`. properties: error: type: string code: type: string description: >- A machine-readable code, on the failures that carry one: `LLM_SERVICE_TIER_UNAVAILABLE` for a processing speed the agent cannot use. message: type: string path: type: string description: >- With `LLM_SERVICE_TIER_UNAVAILABLE`: the refused field, `agent_model_config.llm_service_tier`. reason: type: string enum: - model - organization description: >- With `LLM_SERVICE_TIER_UNAVAILABLE`: `model` when the language model does not offer the speed (or the value is not a speed at all), `organization` when your organization does not have it. tier: type: string description: With `LLM_SERVICE_TIER_UNAVAILABLE`, the refused value, as text. provider: type: string description: >- With `LLM_SERVICE_TIER_UNAVAILABLE`, the agent's language model provider. model: type: string description: With `LLM_SERVICE_TIER_UNAVAILABLE`, the agent's language model. issues: type: array items: type: object properties: path: type: string description: Dotted path of the offending field code: type: string message: type: string details: type: array items: {} 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 ValidationFailed: description: >- The request body or query string failed validation. `error` lists each problem prefixed with the field it concerns; `issues` carries the same information per field. content: application/json: schema: $ref: '#/components/schemas/ValidationError' example: error: 'name: String must contain at least 1 character(s)' issues: - path: name code: too_small message: String must contain at least 1 character(s) minimum: 1 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.