> ## Documentation Index > Fetch the complete documentation index at: https://docs.itellico.ai/llms.txt > Use this file to discover all available pages before exploring further. # Create phone number > Create a phone number attached to a SIP trunk. LiveKit trunks are synchronized automatically; FusionPBX linking is performed when applicable. ## OpenAPI ````yaml https://api.itellico.ai/v1/openapi.json post /v1/accounts/{account_id}/phone-numbers openapi: 3.1.0 info: title: itellicoAI API v1 version: 1.0.0 description: >- Public REST API for managing accounts, agents, telephony resources, and conversations. Authentication is via API key in the `X-API-Key` header. termsOfService: https://itellico.ai/legal/terms-and-conditions/ contact: name: itellicoAI Support email: support@itellico.ai license: name: Proprietary servers: - url: https://api.itellico.ai description: Production security: - APIKeyAuth: [] tags: - name: Accounts description: >- Identify the current account context and fetch core account metadata to bootstrap API usage. - name: Subaccounts description: >- Create and manage child accounts under a parent to model tenant hierarchies and delegated access. - name: Agents description: >- Define and configure conversational agents (model, transcriber, voice, behavior) used in calls and automations. - name: Providers description: >- Discover available AI model, transcriber, and voice catalogs for the current account when configuring agents. - name: Phone Numbers description: >- Manage BYOC phone numbers bound to your account; route inbound calls to agents and enable outbound calling. - name: SIP Trunks description: >- Manage BYOC SIP trunk connectivity (origination/termination endpoints and allowed IPs) used by phone numbers. - name: Calls description: >- Create, list, inspect, and connect voice calls across phone and web channels. - name: Conversations description: List and inspect conversation activity across web and telephony channels. - name: Analytics description: Usage analytics and reporting endpoints for conversation activity. paths: /v1/accounts/{account_id}/phone-numbers: post: tags: - Phone Numbers summary: Create phone number description: >- Create a phone number attached to a SIP trunk. LiveKit trunks are synchronized automatically; FusionPBX linking is performed when applicable. operationId: createPhoneNumber parameters: - in: path name: account_id schema: format: uuid4 title: Account Id type: string required: true requestBody: content: application/json: schema: $ref: '#/components/schemas/CreateByocPhoneNumberDTO' required: true responses: '201': description: Created content: application/json: schema: $ref: '#/components/schemas/PhoneNumberV1Out' '400': description: Bad Request content: application/json: schema: $ref: '#/components/schemas/ErrorSchema' '502': description: Bad Gateway content: application/json: schema: $ref: '#/components/schemas/ErrorSchema' security: - APIKeyAuth: [] components: schemas: CreateByocPhoneNumberDTO: properties: sip_trunk_id: description: SIPTrunk UUID title: Sip Trunk Id type: string number: anyOf: - type: string - type: 'null' description: E.164 phone number title: Number name: anyOf: - type: string - type: 'null' description: Friendly name title: Name inbound_agent_id: anyOf: - type: string - type: 'null' description: Inbound Agent UUID title: Inbound Agent Id required: - sip_trunk_id title: CreateByocPhoneNumberDTO type: object PhoneNumberV1Out: properties: id: format: uuid4 title: Id type: string number: anyOf: - type: string - type: 'null' title: Number sip_trunk: anyOf: - $ref: '#/components/schemas/SIPTrunkBaseV1Out' - type: 'null' inbound_agent: anyOf: - $ref: '#/components/schemas/NumberAgentV1Out' - type: 'null' spam_data: anyOf: - additionalProperties: true type: object - type: 'null' title: Spam Data friendly_name: anyOf: - maxLength: 100 type: string - type: 'null' title: Friendly Name tellows_data: anyOf: - type: object - type: 'null' description: >- Tellows spam check data including score, complaints, caller info, and check timestamp title: Tellows Data required: - id title: PhoneNumberV1Out type: object ErrorSchema: description: |- Standard error response payload for all API endpoints. Follows industry best practices (similar to Stripe, RetellAI): - code: Machine-readable error identifier for programmatic handling - message: Human-readable description for display - detail: Optional additional context for debugging - errors: Optional list of field-level validation errors examples: - code: not_found detail: Agent with UUID 123e4567-e89b-12d3-a456-426614174000 does not exist message: Resource not found - code: validation_error errors: - field: body.email message: Invalid email format type: value_error - field: body.name message: Field required type: missing message: Validation failed properties: code: description: Machine-readable error code (e.g., 'not_found', 'validation_error') title: Code type: string message: description: Human-readable error message title: Message type: string detail: anyOf: - type: string - type: 'null' description: Optional detailed context for debugging title: Detail errors: anyOf: - items: $ref: '#/components/schemas/FieldErrorSchema' type: array - type: 'null' description: Field-level validation errors (for 422 responses) title: Errors required: - code - message title: ErrorSchema type: object SIPTrunkBaseV1Out: properties: id: format: uuid4 title: Id type: string is_managed: title: Is Managed type: boolean name: description: Display name for this SIP trunk maxLength: 100 title: Name type: string required: - id - is_managed - name title: SIPTrunkBaseV1Out type: object NumberAgentV1Out: properties: id: format: uuid4 title: Id type: string name: maxLength: 200 title: Name type: string avatar: anyOf: - type: string - type: 'null' title: Avatar required: - id - name title: NumberAgentV1Out type: object FieldErrorSchema: description: Schema for individual field validation errors. properties: field: description: Field path (e.g., 'body.name', 'query.page') title: Field type: string message: description: Human-readable error message title: Message type: string type: description: Error type (e.g., 'value_error', 'type_error') title: Type type: string required: - field - message - type title: FieldErrorSchema type: object securitySchemes: APIKeyAuth: type: apiKey in: header name: X-API-Key ````