> ## 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 a message > Use this endpoint to send a message to one or more recipients (up to 10 recipients). If you want to use channels other than SMS (Viber, WhatsApp, etc.), you need to use the `flow` property. ## OpenAPI ````yaml /openapi/en/json/jsonapi_v2.yaml post /message openapi: 3.1.0 info: title: JSON API description: > API for sending messages via SMS, Viber, WhatsApp and other communication channels. ## JSON API v2 API key is required for all requests. You can find your API key in your [account settings](https://app.smsmanager.com/api-cloud). API versions (http-api and xml-api) are deprecated also and you should use this JSON API v2 instead. version: v2 contact: url: https://smsmanager.cz email: cc@smsmanager.cz servers: - url: https://api.smsmngr.com/v2 description: Responds with your request data security: [] tags: - name: sending x-displayName: Sending messages description: | For sending messages use one of the following endpoints. - `/message` for sending a message up to 10 recipients - `/messages` for sending multiple messages (up to 10 messages at once) - `/simple/message` for sending a simple message (GET and POST) paths: /message: post: tags: - sending summary: Send a message description: > Use this endpoint to send a message to one or more recipients (up to 10 recipients). If you want to use channels other than SMS (Viber, WhatsApp, etc.), you need to use the `flow` property. requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/Message' examples: Simple message: value: body: Test message to: - phone_number: '420777123456' Message with flow: value: body: Test message to: - phone_number: '420777123456' flow: - sms: sender: SmsManager gateway: high ttl: 10 Scheduled message: value: body: Meeting reminder to: - phone_number: '420777123456' datetime: '2025-01-11T10:00:00Z' Message with callback and payload: value: body: Order shipped to: - phone_number: '420777123456' callback: https://example.com/delivery payload: order_id: ORD-1001 Unicode SMS with custom TTL: value: body: 'Привет, Ваш код: 1234' to: - phone_number: '420777123456' tag: transactional flow: - sms: sender: SmsManager type: utf ttl: 5 responses: '200': description: Messages sent successfully content: application/json: schema: $ref: '#/components/schemas/MessageResponse' '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 security: - x-api-key: [] 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. The international format (E.164, without leading `+` or `00`) is recommended but also another format is accepted (before accepting the request, we will convert it to the international format). example: '420777123456' required: - phone_number callback: type: string format: uri description: >- Callback URL for receiving delivery notifications (Webhook, see [Webhooks](#tag/Webhooks)). 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). params: type: object description: >- By providing this object, you can pass special parameters to the message. Ask us how to use this parameter for shortening links or other features. datetime: type: string format: date-time description: Scheduled time for sending the message. Always in UTC timezone. example: '2025-01-11T10:00:00Z' 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. example: '08:00' end: type: string description: End time for the scheduled time. example: '21:00' tz: type: string description: Timezone for the scheduled time. example: Europe/Prague, Europe/London, Europe/Berlin, America/New_York default: UTC flow: type: array description: >- A list of communication channels for the message flow. If defined, must not be empty. You can use multiple channels, the order of channels is important (first channel is the first to be used, if the first channel is not available or recipient does not accept it, the second channel is used, etc.). items: type: object additionalProperties: false minProperties: 1 maxProperties: 1 properties: sms: type: object properties: body: type: string maxLength: 1000 description: >- This definition of message body here 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: string 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 description: Time to live in minutes. 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 here 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 required: - title - url properties: title: type: string url: type: string format: uri ttl: type: integer description: Time to live in minutes. required: - body - sender whatsapp_text: type: object properties: body: type: string description: >- This definition of message body here have higher priority than the one defined in the root object. You can use custom body of message only when the recipient already reply to your template message or send you a message first. maxLength: 1000 sender: type: string description: >- Phone Number ID of registered WhatsApp number. You can find it in your [WhatsApp settings](https://app.smsmanager.com/whatsapp). examples: - '514578330250514' 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. maxLength: 100 sender: type: string description: >- Phone Number ID of registered WhatsApp number. You can find it in your [WhatsApp settings](https://app.smsmanager.com/whatsapp). examples: - '514578330250514' params: type: array items: type: string description: >- If your template has parameters, you need to pass values for them here. params_header: type: array items: type: string description: >- If your template has header with parameter, you need to pass value for it here. params_buttons: type: array items: type: string description: >- If your template buttons have 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 - language - sender payload: type: object description: > You can send the message payload, where you can define any parameters for the message. This object is returned in the delivery notification and replies. example: user_id: '123456' MessageResponse: type: object properties: request_id: type: string description: Unique request identifier. accepted: type: array items: type: object properties: key: type: string description: Index of the original recipient from the `to` array. message_id: type: string description: Unique message identifier for accepted message. rejected: type: array items: type: object properties: key: type: string description: Index of the original recipient from the `to` array. securitySchemes: x-api-key: type: apiKey in: header name: x-api-key ````