> ## Documentation Index > Fetch the complete documentation index at: https://docs.kapso.ai/llms.txt > Use this file to discover all available pages before exploring further. # Perform call action > Perform various call actions via the WhatsApp Calling API. **Proxy endpoint**: Proxies directly to Meta Graph API. Supports the following actions: - **connect**: Initiate an outbound call to a WhatsApp user - **pre_accept**: Pre-establish WebRTC connection before accepting call - **accept**: Accept an inbound call from a WhatsApp user - **reject**: Reject an inbound call - **terminate**: End an active call ## OpenAPI ````yaml /api/meta/whatsapp/openapi-whatsapp.yaml post /{phone_number_id}/calls openapi: 3.1.0 info: title: Kapso Meta Proxy API version: 1.0.0 description: > Kapso's Meta Proxy API provides a unified interface to WhatsApp Business Platform with enhanced features and Kapso-specific extensions. This API acts as a proxy layer between your application and WhatsApp, adding: - Simplified authentication with project-level API keys - Enhanced message metadata and tracking - Conversation management capabilities - Voice call integration - Extended contact and template management ## Base URL All API requests are made to: `https://api.kapso.ai/meta/whatsapp/v24.0` ## Authentication The API supports authentication via **X-API-Key header** (recommended): ``` X-API-Key: your_project_api_key ``` Alternative: Bearer token authentication is also supported for backward compatibility: ``` Authorization: Bearer your_access_token ``` Note: X-API-Key is the recommended authentication method for the Meta Proxy API. contact: name: Kapso Support url: https://kapso.ai email: dev@kap.so servers: - url: https://api.kapso.ai/meta/whatsapp/v24.0 description: Production server security: - ApiKeyAuth: [] - BearerAuth: [] tags: - name: Messages description: Send and retrieve WhatsApp messages - name: Conversations description: Manage WhatsApp conversations - name: Contacts description: Manage WhatsApp contacts - name: Templates description: Manage message templates - name: Media description: Upload and retrieve media files - name: Calls description: Manage voice calls - name: Settings description: Account settings and configuration - name: Business Profile description: Business profile management - name: Phone Numbers description: Phone number management - name: Flows description: WhatsApp Flow management (Beta) - name: Block Users description: Block and unblock WhatsApp users - name: Usernames description: Reserve and manage WhatsApp business usernames paths: /{phone_number_id}/calls: parameters: - name: phone_number_id in: path required: true description: WhatsApp Business Phone Number ID schema: type: string example: '110987654321' post: tags: - Calls summary: Perform call action description: | Perform various call actions via the WhatsApp Calling API. **Proxy endpoint**: Proxies directly to Meta Graph API. Supports the following actions: - **connect**: Initiate an outbound call to a WhatsApp user - **pre_accept**: Pre-establish WebRTC connection before accepting call - **accept**: Accept an inbound call from a WhatsApp user - **reject**: Reject an inbound call - **terminate**: End an active call operationId: performCallAction requestBody: required: true content: application/json: schema: type: object required: - messaging_product - action properties: messaging_product: type: string enum: - whatsapp example: whatsapp to: type: string description: Recipient WhatsApp ID (required for connect action) example: '15551234567' call_id: type: string description: Call ID (required for pre_accept, accept, reject, terminate) example: wacid.ABGGFjFVU2AfAgo6V-Hc5eCgK5Gh action: type: string enum: - connect - pre_accept - accept - reject - terminate description: The action to perform example: accept session: type: object description: >- WebRTC session description (required for connect, pre_accept, accept) properties: sdp_type: type: string enum: - offer - answer description: >- SDP type - "offer" for connect, "answer" for pre_accept/accept example: answer sdp: type: string description: >- Session Description Protocol (SDP) compliant with RFC 8866 example: >- v=0\r\no=- 7669997803033704573 2 IN IP4 127.0.0.1\r\ns=-\r\n... biz_opaque_callback_data: type: string description: >- Arbitrary tracking string (max 512 chars, optional for connect/accept) maxLength: 512 example: tracking_id_12345 examples: initiate_call: summary: Initiate outbound call (connect) value: messaging_product: whatsapp to: '15551234567' action: connect session: sdp_type: offer sdp: "v=0\r\no=- 6314352886888624490 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 ccd3f422-8d7d-49c9-936c-a152979ee4fa\r\nm=audio 9 UDP/TLS/RTP/SAVPF 111 63 9 0 8 110 126\r\nc=IN IP4 0.0.0.0\r\na=rtcp:9 IN IP4 0.0.0.0\r\na=ice-ufrag:/PSS\r\na=ice-pwd:buBIz+JlbmakiCT7JdJIq/j0\r\na=ice-options:trickle\r\na=fingerprint:sha-256 43:08:34:16:67:E3:D9:A2:F5:AA:6A:AE:03:97:C8:D5:B8:F2:4B:40:79:C8:1A:44:53:69:4B:9C:89:88:D7:22\r\na=setup:active\r\na=mid:0\r\na=sendrecv\r\na=rtcp-mux\r\na=rtpmap:111 opus/48000/2\r\n" biz_opaque_callback_data: call_session_abc123 pre_accept_call: summary: Pre-accept call (establish connection early) value: messaging_product: whatsapp call_id: wacid.ABGGFjFVU2AfAgo6V-Hc5eCgK5Gh action: pre_accept session: sdp_type: answer sdp: "v=0\r\no=- 7669997803033704573 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 3c28addc-03b7-4170-b5cd-535bfe767e75\r\nm=audio 9 UDP/TLS/RTP/SAVPF 111 63 9 0 8 110 126\r\nc=IN IP4 0.0.0.0\r\na=rtcp:9 IN IP4 0.0.0.0\r\na=ice-ufrag:6O0H\r\na=ice-pwd:TYCbtfOrBMPpfxFRgSbYnuTI\r\na=setup:active\r\na=mid:0\r\na=sendrecv\r\na=rtcp-mux\r\na=rtpmap:111 opus/48000/2\r\n" accept_call: summary: Accept inbound call value: messaging_product: whatsapp call_id: wacid.ABGGFjFVU2AfAgo6V-Hc5eCgK5Gh action: accept session: sdp_type: answer sdp: "v=0\r\no=- 7669997803033704573 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 3c28addc-03b7-4170-b5cd-535bfe767e75\r\nm=audio 9 UDP/TLS/RTP/SAVPF 111 63 9 0 8 110 126\r\nc=IN IP4 0.0.0.0\r\na=rtcp:9 IN IP4 0.0.0.0\r\na=ice-ufrag:6O0H\r\na=ice-pwd:TYCbtfOrBMPpfxFRgSbYnuTI\r\na=setup:active\r\na=mid:0\r\na=sendrecv\r\na=rtcp-mux\r\na=rtpmap:111 opus/48000/2\r\n" biz_opaque_callback_data: session_tracking_xyz reject_call: summary: Reject inbound call value: messaging_product: whatsapp call_id: wacid.ABGGFjFVU2AfAgo6V-Hc5eCgK5Gh action: reject terminate_call: summary: Terminate active call value: messaging_product: whatsapp call_id: wacid.ABGGFjFVU2AfAgo6V-Hc5eCgK5Gh action: terminate responses: '200': description: Action performed successfully content: application/json: schema: type: object properties: messaging_product: type: string enum: - whatsapp example: whatsapp success: type: boolean example: true calls: type: array description: Returned for connect action items: type: object properties: id: type: string example: wacid.ABGGFjFVU2AfAgo6V examples: connect_success: summary: Initiate call success value: messaging_product: whatsapp calls: - id: wacid.ABGGFjFVU2AfAgo6V-Hc5eCgK5Gh action_success: summary: Other actions success value: messaging_product: whatsapp success: true '400': description: Bad request (invalid action or parameters) content: application/json: schema: $ref: '#/components/schemas/Error' '401': description: Unauthorized content: application/json: schema: $ref: '#/components/schemas/Error' components: schemas: Error: type: object required: - error properties: error: type: object required: - message - type - code properties: message: type: string description: Human-readable error message example: Invalid phone number format type: type: string description: Error category example: OAuthException code: type: integer description: Error code example: 400 error_subcode: type: integer description: More specific error code example: 1001 fbtrace_id: type: string description: Facebook trace ID for debugging example: AXk7s_8dR4eVHp9Kq2MmNlO securitySchemes: ApiKeyAuth: type: apiKey in: header name: X-API-Key description: > Project API key for authentication. This is the recommended authentication method. Get your API key from the Kapso dashboard under Integrations > API keys. BearerAuth: type: http scheme: bearer bearerFormat: JWT description: | Bearer token authentication (alternative method). Note: X-API-Key authentication is recommended for the Meta Proxy API. ````