> ## Documentation Index > Fetch the complete documentation index at: https://developers.smsmanager.com/llms.txt > Use this file to discover all available pages before exploring further. # Send multiple messages ## OpenAPI ````yaml /openapi/en/json/jsonapi_v1.yaml post /messages openapi: 3.1.0 info: title: JSON API description: > API for sending messages via SMS, Viber, WhatsApp and other communication channels. ## JSON API v1 API key is required for all requests. You can find your API key in your [account settings](https://app.smsmanager.com/api-cloud). This JSON API v1 is deprecated now and you should use this [JSON API v2](/api-json-v2/) instead. version: v2 contact: url: https://smsmanager.cz email: cc@smsmanager.cz servers: - url: https://api.smsmngr.com/v1 description: Responds with your request data security: - xapikey: [] paths: /messages: post: tags: - Sending messages summary: Send multiple messages requestBody: required: true content: application/json: schema: type: array minItems: 1 maxItems: 10 items: $ref: '#/components/schemas/Message' responses: '200': description: Messages sent successfully content: application/json: schema: $ref: '#/components/schemas/MessagesResponse' '400': description: Bad request content: application/json: schema: type: object properties: Message: type: string description: Error message. example: >- User is not authorized to access this resource with an explicit deny components: schemas: Message: type: object required: - body - to properties: body: type: string maxLength: 1000 description: The message body (if not defined in the flow). to: type: array minItems: 1 maxItems: 10 description: List of recipients. items: type: object properties: phone_number: type: string description: >- Recipient's phone number in international format (E.164) without leading `+` or `00`. examples: - 420777123456 required: - phone_number callback: type: string format: uri description: Callback URL for delivery notifications. tag: type: string default: promotional description: >- Tag for the message. You can use it to group messages (e.g. by campaign id). There are also some special tags you can use: `priority` (for priority messages), `transactional` (for transactional messages). datetime: type: string format: date-time description: Scheduled time for sending the message. Always in UTC timezone. examples: - '2025-01-11T10:00:00.000Z' delivery_time: type: object properties: days: type: array items: type: string enum: - monday - tuesday - wednesday - thursday - friday - saturday - sunday description: Days of the week for the scheduled time. start: type: string description: Start time for the scheduled time. examples: - '08:00' end: type: string description: End time for the scheduled time. examples: - '21:00' flow: type: array description: >- A list of communication channels for the message flow. If defined, must not be empty. items: type: object properties: sms: type: object properties: body: type: string maxLength: 1000 description: >- This definition of message body have higher priority than the one defined in the root object. sender: type: string description: >- Alphanumeric sender name (max. 11 characters, pre-registration may be required) or dedicated virtual number (without `+`). examples: - Mojefirma - 420777123456 gateway: type: enum enum: - high - direct - custom default: high description: >- Use `direct` if you use dedicated virtual number. Use `custom` if you use SIM hosting. ttl: type: integer type: type: string enum: - sms - utf default: utf description: >- Set `utf` if you want to keep unicode characters in the message. Set `sms` if you want to convert or remove unicode from message to keep maximal capacity in SMS. required: - body viber: type: object properties: body: type: string maxLength: 1000 description: >- This definition of message body have higher priority than the one defined in the root object. sender: type: string description: >- Use the name of the sender you have pre-registered for your Viber Business Message. buttons: type: array maxItems: 1 items: type: object properties: title: required: true type: string url: required: true type: string format: uri ttl: type: integer description: Time to live in minutes. required: - body - sender whatsapp_text: type: object properties: body: type: string sender: type: string required: - body - sender whatsapp_template: type: object properties: template_name: type: string description: >- The name of the template you have pre-registered and approved before use. params: type: array items: type: string description: >- If your template has parameters, you need to pass values for them here. language: type: string examples: - en - cs description: >- The language of the template (you can have multiple languages for the same template). ttl: type: integer description: Time to live in minutes. required: - template_name payload: type: object description: > *Customizable object* You can even create for the message, where you can define any parameters for the message. This object is returned in the delivery notification and replies. examples: value: user_id: '123456' MessagesResponse: type: object properties: requestId: type: string description: Unique request identifier. accepted: type: array items: type: object properties: key: type: string description: Index of the original request from the body array. messageId: type: string description: Unique message identifier for each request in the body array. rejected: type: array items: type: object properties: key: type: string description: Index of the original request from the body array. ````