> ## Documentation Index > Fetch the complete documentation index at: https://docs.leadstaker.com/llms.txt > Use this file to discover all available pages before exploring further. # Send a message to a phone number > Starts or reuses a chat for the number and answers with its id. ## OpenAPI ````yaml /api-reference/openapi.json post /v1/messages/send-by-phone openapi: 3.0.3 info: title: Leadstaker API version: 1.0.0 description: Public REST API for Leadstaker projects. servers: - url: https://n-api.leadstaker.com description: Production security: [] tags: - name: Fields description: >- Custom field definitions, both the built-in ones and the ones a project creates. - name: Field groups description: Sections that organize custom fields in the interface. - name: Deals description: Opportunities moving through a pipeline, each tied to a contact. - name: Contacts description: >- People inside a project, holding the custom field values collected about them. - name: Messages description: Individual messages inside a chat, inbound and outbound. - name: Chats description: Conversations with a contact over a connected channel. - name: Loss reasons description: The catalog of reasons a deal can be marked as lost. - name: Pipelines description: Ordered sets of stages a deal travels through. - name: Stages description: Steps inside a pipeline, including the built-in open and closed ones. - name: Tags description: Free-form labels attached to deals. - name: Notes description: >- Free text attached to a contact or a deal, written by a user, an agent, or the system. paths: /v1/messages/send-by-phone: post: tags: - Messages summary: Send a message to a phone number description: Starts or reuses a chat for the number and answers with its id. operationId: postMessagesSendByPhone parameters: [] requestBody: required: true content: application/json: schema: anyOf: - type: object properties: phone: type: string minLength: 1 channelId: type: string minLength: 1 contactId: type: string minLength: 1 method: type: string enum: - MESSAGES messages: type: array items: type: string minLength: 1 required: - phone - channelId - method - messages additionalProperties: false - type: object properties: phone: type: string minLength: 1 channelId: type: string minLength: 1 contactId: type: string minLength: 1 method: type: string enum: - AI required: - phone - channelId - method additionalProperties: false - type: object properties: phone: type: string minLength: 1 channelId: type: string minLength: 1 contactId: type: string minLength: 1 method: type: string enum: - TEMPLATE templateId: type: string minLength: 1 variables: type: array items: type: object properties: name: type: string minLength: 1 value: type: string minLength: 1 required: - name - value additionalProperties: false required: - phone - channelId - method - templateId additionalProperties: false - type: object properties: phone: type: string minLength: 1 channelId: type: string minLength: 1 contactId: type: string minLength: 1 method: type: string enum: - MESSAGE message: anyOf: - type: object properties: type: type: string enum: - TEXT content: type: object properties: text: type: string minLength: 1 required: - text additionalProperties: false required: - type - content additionalProperties: false - type: object properties: type: type: string enum: - IMAGE content: type: object properties: caption: type: string media: type: object properties: url: type: string format: uri mimeType: type: string minLength: 1 fileId: type: string minLength: 1 required: - url additionalProperties: false required: - media additionalProperties: false required: - type - content additionalProperties: false - type: object properties: type: type: string enum: - VIDEO content: type: object properties: caption: type: string media: type: object properties: url: type: string format: uri mimeType: type: string minLength: 1 fileId: type: string minLength: 1 isAnimated: type: boolean default: false required: - url additionalProperties: false required: - media additionalProperties: false required: - type - content additionalProperties: false - type: object properties: type: type: string enum: - AUDIO content: type: object properties: caption: type: string media: type: object properties: url: type: string format: uri mimeType: type: string minLength: 1 fileId: type: string minLength: 1 required: - url - fileId additionalProperties: false required: - media additionalProperties: false required: - type - content additionalProperties: false - type: object properties: type: type: string enum: - DOCUMENT content: type: object properties: caption: type: string media: type: object properties: url: type: string format: uri mimeType: type: string minLength: 1 fileId: type: string minLength: 1 filename: type: string required: - url additionalProperties: false required: - media additionalProperties: false required: - type - content additionalProperties: false - type: object properties: type: type: string enum: - STICKER content: type: object properties: caption: type: string media: type: object properties: url: type: string format: uri mimeType: type: string minLength: 1 fileId: type: string minLength: 1 isAnimated: type: boolean default: false required: - url additionalProperties: false required: - media additionalProperties: false required: - type - content additionalProperties: false - type: object properties: type: type: string enum: - CONTACT content: type: object properties: name: type: string minLength: 1 phones: type: array items: type: string emails: type: array items: type: string minLength: 1 format: email urls: type: array items: type: string minLength: 1 format: uri additionalProperties: false required: - type - content additionalProperties: false - type: object properties: type: type: string enum: - LOCATION content: type: object properties: latitude: type: number longitude: type: number name: type: string address: type: string required: - latitude - longitude additionalProperties: false required: - type - content additionalProperties: false - type: object properties: type: type: string enum: - URL content: type: object properties: text: type: string minLength: 1 showPreview: type: boolean required: - text additionalProperties: false required: - type - content additionalProperties: false required: - phone - channelId - method - message additionalProperties: false responses: '200': description: Success content: application/json: schema: type: object properties: chatId: type: string minLength: 1 required: - chatId additionalProperties: false example: chatId: 6713cc481f52bb0014a7d3e9 '401': description: Missing or invalid credentials content: application/json: schema: $ref: '#/components/schemas/Error' '422': description: The payload failed validation content: application/json: schema: $ref: '#/components/schemas/Error' security: - apiKey: [] components: schemas: Error: type: object required: - errorCode - message - status properties: errorCode: type: string message: type: string status: type: integer errors: type: array items: type: object required: - field - code - message properties: field: type: string code: type: string message: type: string securitySchemes: apiKey: type: apiKey in: header name: x-api-key ````