> ## Documentation Index > Fetch the complete documentation index at: https://docs.xpressbot.org/llms.txt > Use this file to discover all available pages before exploring further. # Send interactive message (buttons or link) > Send a WhatsApp message with reply buttons (type=button, 1 to 3 buttons) or one call-to-action link button (type=cta_url), within the 24-hour session window, via the authorized channel. When the customer taps a reply button, the reply arrives like any message (button_id is the id you gave). Texts longer than the WhatsApp limits are refused with a clear error, not cut. Authentication: API key via X-API-Key header (or Authorization: Bearer). Permissions: User API key Rate limit: api_messaging — 20 requests/min per API user. ## OpenAPI ````yaml /api-reference/workspace.openapi.json post /api/workspace/v1/whatsapp/message/interactive openapi: 3.1.0 info: title: Workspace API version: 1.0.0 description: >- Manage contacts, labels, custom fields, WhatsApp messaging, and automations for your workspace. Generate your API key in the Developer Portal (profile menu → Developer) and send it in the `X-API-Key` header, or as `Authorization: Bearer `. Never put the key in the URL. Every endpoint accepts POST with a JSON body, and also accepts GET with the same parameters as query-string values. All responses use the envelope `{ success, data?, message?, error? }`. servers: - url: https://YOUR_DOMAIN description: Your deployment, for example https://app.example.com security: [] tags: - name: Channels description: Workspace API — Channels - name: Contacts description: Workspace API — Contacts - name: Custom Fields description: Workspace API — Custom Fields - name: Labels description: Workspace API — Labels - name: WhatsApp description: Workspace API — WhatsApp - name: Automations description: Workspace API — Automations paths: /api/workspace/v1/whatsapp/message/interactive: post: tags: - WhatsApp summary: Send interactive message (buttons or link) description: >- Send a WhatsApp message with reply buttons (type=button, 1 to 3 buttons) or one call-to-action link button (type=cta_url), within the 24-hour session window, via the authorized channel. When the customer taps a reply button, the reply arrives like any message (button_id is the id you gave). Texts longer than the WhatsApp limits are refused with a clear error, not cut. Authentication: API key via X-API-Key header (or Authorization: Bearer). Permissions: User API key Rate limit: api_messaging — 20 requests/min per API user. parameters: - name: channelId in: query required: false description: Channel id. Auto-selects when omitted. schema: type: string example: ch_123 - name: to in: query required: false description: Recipient phone or WhatsApp BSUID. schema: type: string example: '919876543210' - name: type in: query required: false description: button (reply buttons) or cta_url (one link button). schema: type: string example: YOUR_TYPE - name: body in: query required: false description: Message text, up to 1024 characters. schema: type: string example: YOUR_BODY - name: buttons in: query required: false description: >- type=button only. 1 to 3 items { id, title }: title up to 20 characters, id (optional, up to 256 characters) comes back as button_id when tapped. Titles and ids must be different. JSON string for GET. schema: type: array items: {} example: [] - name: buttonLabel in: query required: false description: type=cta_url only. Text on the link button, up to 20 characters. schema: type: string example: YOUR_BUTTONLABEL - name: buttonUrl in: query required: false description: type=cta_url only. The link to open (http or https). schema: type: string example: YOUR_BUTTONURL - name: header in: query required: false description: Header text, up to 60 characters. Not together with headerUrl. schema: type: string example: YOUR_HEADER - name: headerType in: query required: false description: image | video | document. Required with headerUrl. schema: type: string example: YOUR_HEADERTYPE - name: headerUrl in: query required: false description: Public URL of the header file. schema: type: string example: YOUR_HEADERURL - name: headerFilename in: query required: false description: File name shown for a document header. schema: type: string example: YOUR_HEADERFILENAME - name: footer in: query required: false description: Footer text, up to 60 characters. schema: type: string example: YOUR_FOOTER requestBody: required: true content: application/json: schema: type: object required: - to - type - body properties: channelId: type: string description: Channel id. Auto-selects when omitted. example: ch_123 to: type: string description: Recipient phone or WhatsApp BSUID. example: '919876543210' type: type: string description: button (reply buttons) or cta_url (one link button). example: YOUR_TYPE body: type: string description: Message text, up to 1024 characters. example: YOUR_BODY buttons: type: array items: {} description: >- type=button only. 1 to 3 items { id, title }: title up to 20 characters, id (optional, up to 256 characters) comes back as button_id when tapped. Titles and ids must be different. JSON string for GET. example: [] buttonLabel: type: string description: >- type=cta_url only. Text on the link button, up to 20 characters. example: YOUR_BUTTONLABEL buttonUrl: type: string description: type=cta_url only. The link to open (http or https). example: YOUR_BUTTONURL header: type: string description: >- Header text, up to 60 characters. Not together with headerUrl. example: YOUR_HEADER headerType: type: string description: image | video | document. Required with headerUrl. example: YOUR_HEADERTYPE headerUrl: type: string description: Public URL of the header file. example: YOUR_HEADERURL headerFilename: type: string description: File name shown for a document header. example: YOUR_HEADERFILENAME footer: type: string description: Footer text, up to 60 characters. example: YOUR_FOOTER example: channelId: ch_123 to: '919876543210' type: button body: Your order is ready. Collect it today? buttons: - id: collect_yes title: 'Yes' - id: collect_later title: Later footer: Reply within 24 hours responses: '200': description: 'Success. Envelope: { success:true, data, message? }.' content: application/json: schema: type: object required: - success properties: success: type: boolean example: true data: {} message: type: string pagination: type: object total: type: number example: success: true data: messaging_product: whatsapp messages: - id: wamid.xxx message: Message sent successfully '400': description: >- Missing/invalid parameters. Body has success:false plus error and message. content: application/json: schema: type: object required: - success - error properties: success: type: boolean example: false error: type: string message: type: string '401': description: >- Missing or invalid API key (or session expired for session endpoints). content: application/json: schema: type: object required: - success - error properties: success: type: boolean example: false error: type: string message: type: string '403': description: >- Authenticated but not authorized — wrong permissions or cross-tenant resource. content: application/json: schema: type: object required: - success - error properties: success: type: boolean example: false error: type: string message: type: string '429': description: >- Rate limited. Retry after the Retry-After seconds; see RateLimit-* headers. content: application/json: schema: type: object required: - success - error properties: success: type: boolean example: false error: type: string message: type: string '500': description: >- Unexpected server error. Body has success:false plus error and message. content: application/json: schema: type: object required: - success - error properties: success: type: boolean example: false error: type: string message: type: string security: - apiKeyHeader: [] - bearerAuth: [] components: securitySchemes: apiKeyHeader: type: apiKey in: header name: X-API-Key description: Preferred. API key value directly. bearerAuth: type: http scheme: bearer description: Alternative. API key as the bearer token. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.