> ## Documentation Index > Fetch the complete documentation index at: https://www.bolna.ai/docs/llms.txt > Use this file to discover all available pages before exploring further. # Make Voice AI Call API > Learn how to initiate outbound phone calls using Bolna Voice AI agents. Start making phone calls using the agent ID and recipient's phone number. Places an outbound call from a Bolna agent to a phone number. Returns an `execution_id` you use to track and retrieve the call result. ## Minimal example Only two fields are required — `agent_id` and `recipient_phone_number`. Omit `from_phone_number` to use your account's default number. ```json Minimal request theme={"system"} { "agent_id": "123e4567-e89b-12d3-a456-426655440000", "recipient_phone_number": "+919876543210" } ``` ```json Response theme={"system"} { "message": "done", "status": "queued", "execution_id": "b7140255-af33-4608-8e97-04dd944b8e48" } ``` ## Realistic example with personalization Pass `user_data` to inject variables into your agent's prompt and welcome message (e.g. `{customer_name}` in the prompt becomes "Asha"): ```json Request with personalization theme={"system"} { "agent_id": "123e4567-e89b-12d3-a456-426655440000", "recipient_phone_number": "+919876543210", "from_phone_number": "+918035739222", "user_data": { "customer_name": "Asha", "appointment_day": "Friday" } } ``` ## Tracking the call Use the returned `execution_id` to poll `GET /executions/{execution_id}` for status. The call goes through these stages: ``` queued → initiated → ringing → in-progress → call-disconnected → completed ``` **Wait for `completed`, not `call-disconnected`.** The `call-disconnected` event fires the instant the line drops, but `conversation_duration`, `total_cost`, `recording_url`, and `extracted_data` are not yet populated. The `completed` event (a few seconds later) has all finalized fields. See [Get Execution](/api-reference/executions/get_execution). ## Common 400 errors | Message | Fix | | ------------------------------------ | ------------------------------------------------------- | | `agent_id is required` | Include a valid UUID `agent_id` | | `recipient_phone_number is required` | Phone number must be E.164 format, e.g. `+919876543210` | | Invalid `from_phone_number` | Must be a number purchased in your Bolna account | ## OpenAPI ````yaml POST /call openapi: 3.1.0 info: title: Bolna API description: >- Use and leverage Bolna Voice AI using APIs through HTTP requests from any language in your applications and workflows. license: name: MIT version: 1.0.0 servers: - url: https://api.bolna.ai description: Production server security: - bearerAuth: [] paths: /call: post: description: Initiate calls requestBody: description: Make a phone call from agent content: application/json: schema: required: - agent_id - recipient_phone_number properties: agent_id: type: string format: uuid description: Agent `id` which will initiate the outbound call recipient_phone_number: type: string description: >- Phone number of the recipient along with country code (in [E.164](https://en.wikipedia.org/wiki/E.164) format) from_phone_number: type: string description: >- Phone number of the sender along with country code (in [E.164](https://en.wikipedia.org/wiki/E.164) format). Optional — if omitted, Bolna uses the account's default number. scheduled_at: type: string example: '2024-06-05T16:35:00.000+05:30' description: >- The scheduled date and time in ISO 8601 format with time zone user_data: type: object description: >- Additional user dynamic variables as defined in the agent prompt additionalProperties: true agent_data: type: object description: >- Agent configuration to override the default configuration. Currently, only `voice_id` for the same provider is supported. retry_config: type: object description: >- Configuration for auto-retry of failed calls. See [auto-retry documentation](/auto-retry) for details. properties: enabled: type: boolean default: false description: Enable auto-retry for this call max_retries: type: integer minimum: 1 maximum: 3 default: 3 description: Maximum retry attempts (1-3) retry_on_statuses: type: array items: type: string enum: - no-answer - busy - failed - error default: - no-answer - busy - failed description: Call statuses that trigger a retry retry_on_voicemail: type: boolean default: false description: Whether to retry if call reaches voicemail retry_intervals_minutes: type: array items: type: integer default: - 30 - 60 - 120 description: Delay in minutes before each retry attempt bypass_call_guardrails: type: boolean default: false description: >- Skip time validation checks and make call immediately regardless of agent's calling_guardrails configuration examples: example-1: summary: Example of initiating a call value: agent_id: 123e4567-e89b-12d3-a456-426655440000 recipient_phone_number: '+10123456789' from_phone_number: '+19876543007' scheduled_at: '2025-08-21T10:35:00+00:00' user_data: variable1: value1 variable2: value2 variable3: some phrase as value agent_data: voice_id: Sam required: true responses: '200': description: agent status response content: application/json: schema: $ref: '#/components/schemas/MakeCallStatus' '400': description: unexpected error content: application/json: schema: $ref: '#/components/schemas/Error' components: schemas: MakeCallStatus: properties: message: type: string example: done description: Response message for the call initiated status: type: string enum: - queued example: queued description: Status of the call. execution_id: pattern: >- ^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12} type: string example: 123e4567-e89b-12d3-a456-426614174000 description: Unique `execution_id` or `call_id` identifier of the call. type: object Error: required: - error - message type: object properties: error: type: integer format: int32 message: type: string securitySchemes: bearerAuth: type: http scheme: bearer ````