> ## Documentation Index > Fetch the complete documentation index at: https://docs.ycloud.com/llms.txt > Use this file to discover all available pages before exploring further. # Connect a call > Initiates a WhatsApp call connection. Establishes the initial connection for a WhatsApp call by providing SDP offer information. This endpoint is used for business-initiated calling scenarios. ## OpenAPI ````yaml /openapi/endpoints/ycloud-api-v2.yaml post /whatsapp/calls/connect openapi: 3.0.0 info: description: >- The [YCloud](https://ycloud.com) API is organized around [REST](https://en.wikipedia.org/wiki/Representational_state_transfer). Our API is designed to have predictable, resource-oriented URLs, return [JSON](https://www.json.org) responses, and use standard HTTP response codes and verbs. version: v2 title: YCloud API termsOfService: https://ycloud.com/terms-service contact: email: service@ycloud.com servers: - url: https://api.ycloud.com/v2 description: Base URL security: - api_key: [] tags: - name: Balance - name: Contacts - name: Custom Events - name: Emails - name: SMS - name: Unsubscribers - name: Verify - name: Voices - name: Webhook Endpoints - name: WhatsApp Business Accounts - name: WhatsApp Inbound Messages - name: WhatsApp Media - name: WhatsApp Messages - name: WhatsApp Blocked Users - name: WhatsApp Groups - name: WhatsApp Calling - name: WhatsApp Phone Numbers - name: WhatsApp Templates - name: WhatsApp Flows - name: Meta Business Agent - name: WhatsApp Group Messages externalDocs: description: Homepage url: https://ycloud.com paths: /whatsapp/calls/connect: post: tags: - WhatsApp Calling summary: Connect a call description: >- Initiates a WhatsApp call connection. Establishes the initial connection for a WhatsApp call by providing SDP offer information. This endpoint is used for business-initiated calling scenarios. operationId: whatsapp_call-connect requestBody: content: application/json: schema: $ref: '#/components/schemas/WhatsappCallingConnectRequest' required: true responses: '200': description: The call connection request is successfully accepted. content: application/json: schema: $ref: '#/components/schemas/WhatsappCallingResponse' '400': description: Bad request. Invalid request parameters. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '404': description: The requested resource does not exist. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' components: schemas: WhatsappCallingConnectRequest: type: object description: >- Provide at least one of `to` or `recipient`. If both are provided, `to` takes precedence and `recipient` is ignored. not: allOf: - not: required: - to - not: required: - recipient required: - from - sdpType - sdp properties: from: type: string description: >- The caller's phone number in [E.164](https://en.wikipedia.org/wiki/E.164) format. example: '+6283138205150' to: type: string description: >- The callee's phone number in [E.164](https://en.wikipedia.org/wiki/E.164) format. Required when `recipient` is not provided. example: '+6281361905133' recipient: type: string description: >- The callee's WhatsApp Business-scoped user ID (BSUID) or parent BSUID. Required when `to` is not provided. example: US.1234 sdpType: type: string description: The SDP type, must be "offer" for connection requests. enum: - offer example: offer sdp: type: string description: >- The Session Description Protocol (SDP) offer information compliant with [RFC 8866](https://datatracker.ietf.org/doc/html/rfc8866). Contains media session parameters for establishing the WebRTC connection. example: "v=0\r\no=- 4054442297240208280 2 IN IP4 127.0.0.1\r\ns=-\r\nt=0 0\r\na=group:BUNDLE 0\r\na=extmap-allow-mixed\r\na=msid-semantic: WMS 6c364341-f90d-48e6-b497-76e047e3c31a\r\nm=audio 9 UDP/TLS/RTP/SAVPF 111 63 9 0 8 13 110 126\r\nc=IN IP4 0.0.0.0\r\na=rtcp:9 IN IP4 0.0.0.0\r\na=ice-ufrag:Dpsa\r\na=ice-pwd:oVuOd7HKhA8aWTvspLYACWJe\r\na=ice-options:trickle\r\na=fingerprint:sha-256 0A:A9:64:82:AD:D5:31:08:38:71:1C:C0:08:AA:CE:93:22:F4:17:2C:B6:F1:8F:F1:20:71:38:16:37:18:3F:FA\r\na=setup:actpass\r\na=mid:0\r\na=extmap:1 urn:ietf:params:rtp-hdrext:ssrc-audio-level\r\na=extmap:2 http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time\r\na=extmap:3 http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01\r\na=extmap:4 urn:ietf:params:rtp-hdrext:sdes:mid\r\na=sendrecv\r\na=msid:6c364341-f90d-48e6-b497-76e047e3c31a fa42cdbe-8696-4ee8-bce0-0919d86a223f\r\na=rtcp-mux\r\na=rtcp-rsize\r\na=rtpmap:111 opus/48000/2\r\na=rtcp-fb:111 transport-cc\r\na=fmtp:111 minptime=10;useinbandfec=1\r\na=rtpmap:63 red/48000/2\r\na=fmtp:63 111/111\r\na=rtpmap:9 G722/8000\r\na=rtpmap:0 PCMU/8000\r\na=rtpmap:8 PCMA/8000\r\na=rtpmap:13 CN/8000\r\na=rtpmap:110 telephone-event/48000\r\na=rtpmap:126 telephone-event/8000\r\na=ssrc:3208712354 cname:bg/Ix8uTnsTsiMoe\r\na=ssrc:3208712354 msid:6c364341-f90d-48e6-b497-76e047e3c31a fa42cdbe-8696-4ee8-bce0-0919d86a223f\r\n" WhatsappCallingResponse: type: object required: - success properties: wacid: type: string description: The WhatsApp call ID associated with this calling operation. example: >- wacid.HBgNNjI4MTM2MTkwNTEzMxUCABEYIDNENjg2OEMzNTFFRDkwRkUxRUE1RTgxNjY1NjJCQUJBHBgNNjI4MzEzODIwNTE1MBUCABUeAA== success: type: boolean description: Indicates whether the calling operation was successful. example: true ErrorResponse: type: object required: - error properties: error: $ref: '#/components/schemas/Error' description: >- Contains the error code and human-readable message for the API error. Error: type: object required: - status - code properties: status: type: integer format: int32 pattern: '[45]\d{2}' description: >- HTTP status code, [RFC 7231, Section 6](https://datatracker.ietf.org/doc/html/rfc7231#section-6). It conveys the HTTP status code used for the convenience of the consumer. example: 404 code: type: string description: >- One of a server-defined error codes. Some `4xx` errors that could be handled programmatically include an error code that briefly explains the error reported. example: NOT_FOUND message: type: string description: >- A human-readable representation of the error. It is intended as an aid to developers and is not suitable for exposure to end users. example: The requested resource does not exist. target: type: string description: The target of the error. example: '' docUrl: type: string description: A URL to more information about the error. example: '' requestId: type: string description: >- Each API request has an associated request ID. It conveys the response header `YCloud-Request-ID` used for the convenience of the consumer. example: req_1KjtKI80IKoaJNa6n6p whatsappApiError: $ref: '#/components/schemas/WhatsappApiError' description: >- The original error object returned by WhatsApp. See [Handling Errors](https://developers.facebook.com/docs/graph-api/guides/error-handling), [Cloud API Error Codes](https://developers.facebook.com/docs/whatsapp/cloud-api/support/error-codes). Note: This field is returned if we tried to request the WhatsApp Business API and got an error response. metaBusinessAgentApiError: $ref: '#/components/schemas/MetaBusinessAgentApiError' description: >- Sanitized upstream details returned when a Meta Business Agent request fails. WhatsappApiError: type: object description: >- The original error object returned by WhatsApp. See [Handling Errors](https://developers.facebook.com/docs/graph-api/guides/error-handling), [Cloud API Error Codes](https://developers.facebook.com/docs/whatsapp/cloud-api/support/error-codes). required: - message - code properties: message: type: string description: A human-readable description of the error. example: HSM Template creation failed code: type: string description: An error code. example: 200002 type: type: string description: Error type. example: OAuthException is_transient: type: boolean description: Whether the error is transient. example: false error_subcode: type: string description: Additional code about the error. example: 2388109 error_user_msg: type: string description: >- The message to display to the user. The language of the message is based on the locale of the API request. example: This message template cannot be created. error_user_title: type: string description: >- The title of the dialog, if shown. The language of the message is based on the locale of the API request. example: Message Cannot Be Submitted fbtrace_id: type: string description: >- Internal support identifier. When reporting a bug related to a Graph API call, include the fbtrace_id to help us find log data for debugging. example: AVGjJ7ia2zJkrHG error_data: description: >- Additional data about the error. A string or map. - For template APIs, this field is a string describing the reason for the error. - For message APIs, this field is a map with property `details` describing the reason for the error. oneOf: - type: string - type: object additionalProperties: true MetaBusinessAgentApiError: type: object description: Sanitized details from a failed Meta Business Agent upstream request. properties: title: type: string detail: type: string type: type: string status: type: integer format: int32 requestId: type: string securitySchemes: api_key: type: apiKey name: X-API-Key in: header ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.