> ## Documentation Index > Fetch the complete documentation index at: https://docs.flowapt.com/llms.txt > Use this file to discover all available pages before exploring further. # Accept Call > Answer a ringing call. Either send your SDP answer to the offer from the call webhook (the audio then flows between WhatsApp and your media server), or send `stream` and FlowIQ answers the call itself and streams the audio to your WebSocket (see Media stream). Scope: send. Answer a ringing call. Either send your SDP answer to the offer from the [`call` webhook](https://docs.flowapt.com/flowiq-api-reference/webhooks#call), after which the audio flows between WhatsApp and your media server, or send `stream` and FlowIQ answers the call itself and streams the audio to your WebSocket ([media stream](https://docs.flowapt.com/flowiq-api-reference/calling.md#stream-the-audio-to-your-own-voice-agent)). If FlowIQ staff have the inbox open, they see the call as answered on another device. ## Basic Usage ```bash theme={null} curl -X POST "https://api.flowiq.live/v1/calls/accept" \ -H "Authorization: Bearer fiq_YOUR_API_KEY" \ -H "Content-Type: application/json" \ -d '{"call_id": "wacid.HBgLMjc4MjAwMDAwMDAVAgARGBI2RjQ3QkU1RjA5Q0UyMkEzQjQA", "sdp": "v=0\r\no=- 4611 2 IN IP4 127.0.0.1\r\n…"}' ``` *** ## Body Parameters | Parameter | Type | Required | Description | | - | - | - | - | | `call_id` | string | Yes | From the `call` webhook (`call.id`) | | `sdp` | string | One of `sdp` / `stream` | Your SDP answer to the offer in `call.session.sdp` | | `stream` | object | One of `sdp` / `stream` | `{ url: "wss://…", format?, headers?, custom_parameters? }`: FlowIQ answers and streams the audio there. `format` is `pcm16_16k` (default), `pcm16_8k`, `pcm16_24k` or `mulaw_8k` | | `biz_opaque_callback_data` | string | No | With `sdp` only. Your own reference (max 512 characters); WhatsApp sends it back on later events for this call | *** ## Response ### Success (200) ```json theme={null} { "organization_id": "a4234f32-…", "success": true, "call_id": "wacid.HBgLMjc4MjAwMDAwMDAVAgARGBI2RjQ3QkU1RjA5Q0UyMkEzQjQA", "action": "accept" } ``` *** ## Errors | Status | When | | - | - | | `400` | `call_id`, or both `sdp` and `stream`, missing (`validation_error`), or WhatsApp refused the action (`whatsapp_rejected`; the `message` says why, e.g. `Parameter value is not valid` for an unknown or finished call) | | `409` | With `stream`: the call is no longer ringing (`call_not_ringing`) | | `401` | Missing or invalid API key | | `403` | The key has no `send` scope | With `stream`, a WebSocket endpoint that does not accept the connection within 8 seconds fails the request (`validation_error`, the message names the reason) and the call keeps ringing. WhatsApp gives you a limited time to answer before the call rings out; accept as soon as your media server has the answer ready. ## OpenAPI ````yaml flowiq-api-reference/openapi-calls.json POST /v1/calls/accept openapi: 3.1.0 info: title: FlowIQ Calling API version: 1.0.0 description: >- Run WhatsApp calls on your FlowIQ number from your own server: answer, decline, end and start calls, ask for call permission, read call history and change the number's calling settings. Every response carries X-Request-Id; errors carry a stable code; POST / PATCH accept Idempotency-Key. servers: - url: https://api.flowiq.live description: FlowIQ Production API security: - BearerAuth: [] paths: /v1/calls/accept: post: tags: - Calling summary: Accept Call description: >- Answer a ringing call. Either send your SDP answer to the offer from the call webhook (the audio then flows between WhatsApp and your media server), or send `stream` and FlowIQ answers the call itself and streams the audio to your WebSocket (see Media stream). Scope: send. operationId: acceptCall requestBody: required: true content: application/json: schema: type: object properties: call_id: type: string description: The call's id from the call webhook example: wacid.HBgLMjc4MjAwMDAwMDAVAgARGBI2RjQ3QkU1RjA5Q0UyMkEzQjQA sdp: type: string description: >- Your SDP answer to the offer in call.session.sdp (leave out when you send stream) biz_opaque_callback_data: type: string maxLength: 512 description: >- Your own reference; WhatsApp sends it back on later events for this call stream: $ref: '#/components/schemas/StreamConfig' required: - call_id responses: '200': description: Success content: application/json: schema: type: object properties: organization_id: type: string format: uuid success: type: boolean call_id: type: string action: type: string enum: - pre_accept - accept - reject - terminate '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' '409': description: The call is no longer ringing (code call_not_ringing); stream only content: application/json: schema: $ref: '#/components/schemas/Error' '429': $ref: '#/components/responses/RateLimited' components: schemas: StreamConfig: type: object description: >- Have FlowIQ answer the call and stream its audio to your WebSocket (media stream), instead of answering with sdp required: - url properties: url: type: string example: wss://agent.example.com/flowiq/stream description: Your WebSocket endpoint (wss:// only) format: type: string enum: - pcm16_16k - pcm16_8k - pcm16_24k - mulaw_8k default: pcm16_16k description: >- Audio format on the socket, both directions. mulaw_8k matches Twilio Media Streams headers: type: object additionalProperties: type: string description: Headers FlowIQ sends when it connects, e.g. Authorization custom_parameters: type: object description: Echoed in the start message (max 4 KB) Error: type: object properties: error: type: string description: Short label (Bad request, Not found, …) code: type: string description: Stable machine-readable code, see Conventions message: type: string request_id: type: string format: uuid description: Quote this to support whatsapp_error_code: type: integer description: WhatsApp's own code, on whatsapp_rejected responses: BadRequest: description: Invalid request, or WhatsApp refused it (the message says why) content: application/json: schema: $ref: '#/components/schemas/Error' example: error: Request failed message: Parameter value is not valid Unauthorized: description: Missing or invalid API key content: application/json: schema: $ref: '#/components/schemas/Error' Forbidden: description: The key lacks the scope, or the person has not given call permission content: application/json: schema: $ref: '#/components/schemas/Error' example: error: Request failed message: Contact has not granted callback permission RateLimited: description: 240 reads or 60 actions per minute per key; Retry-After says when content: application/json: schema: $ref: '#/components/schemas/Error' securitySchemes: BearerAuth: type: http scheme: bearer bearerFormat: fiq_ API key description: >- Your FlowIQ organisation API key (Settings → API Keys), sent as a bearer token. Format: `Bearer fiq_YOUR_API_KEY` ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.