Viber for Business
Our business messaging API supports sending and receiving Viber for Business messages.
Being able to send Viber messages requires requesting access via the Channels portal. Without onboarding with Viber via the portal, you can not make use of this part of the API. Please be aware that Viber needs to verify the legitimacy of your business and your rationale for usage.
Important
Changes effective July 1, 2026: Viber is retiring the legacy transactional message types (plain text, files, and lists sent as transactional) and the current OTP template system. From July 1, all transactional messages must use the new Transactional Template format. Legacy transactional messages sent after this date will be charged at the promotional rate. See the Transactional template messages page for details.
Fact Sheet
| Feature | Remarks |
|---|---|
| delivery notification | Occurs when your message is delivered to the Viber platform. Delivery notifications are sent to the status report webhooks. |
| Transactional template messages | Pre-approved message templates for transactional notifications (e.g. order confirmations, OTP codes). Required for all transactional messaging from July 1, 2026. |
| text messages | The maximum length of a message is 1000 characters. Text formatting like bold, italics, monospace and strikethrough text are supported (see below). |
| media | Media URL attributes should end in the proper file extension. Only one media file is allowed per message; when sending multiple files, each file will be sent in its own message. When the linked media doesn't exist/can't be found, the message will not be sent at all. |
| media: images | Maximum file size for an uploaded image is 200 MB. Supported formats: png, jpeg, jpg, gif. |
| media: video | Maximum file size for an uploaded video file is 200 MB. Maximum duration of the video can be up to 10 minutes. Supported formats: mp4. Server which host the video must include 'Content-Length' in response header. |
| media: document | Maximum file size for an uploaded file is 200 MB. Supported formats: doc(x), xls(x), csv, pdf. |
| suggestion as button | Only 1 button is possible |
| rich card | Only 1 button is possible |
| OTP templates | Predefined OTP templates, configurable with own variables. |
| carousel | Number of items from 2 to 5. Each item can have a image with expected formats png, jpeg, jpg. Each item have two buttons ( one of them optional) |
| list | Number of items from 2 to 5 |
Sending messages
Viber is one of the few channels which uses telephone numbers as recipients. This allows SMS to be used as a fallback delivery channel if the recipient doesn't have the Viber app installed on their mobile device.
Please note that when defining fallback text, it is affected by the maximum size limitations of SMS as described in the section on SMS multipart messaging.
Onboarding
Two-way messaging
Two-way messaging determines whether users can reply to your Viber messages. This setting is configured during onboarding and affects how your messages function.
Two-Way Enabled:
- Users can reply to your messages
- User replies are sent to your message URL webhook
- You receive and can respond to user messages
Two-Way Disabled:
- Users can't reply to your messages
- One-way broadcast communication only
Important: Transactional and Promotional messaging work with two-way, either enabled or disabled.
Message categories
When you onboard to CM.com for Viber for Business, you will need to decide which message category you will be sending. This decision determines your pricing structure and what types of content you can send.
Important: If you try to send promotional messages while onboarded for transactional (or vice versa), your message will not be sent.
| Category | What you can send |
|---|---|
| Promotional | Text, images, image + text, image + text + button, text + button, video, carousels |
| Transactional | Transactional template messages only (from July 1, 2026). Country-specific templates (RU, UA, BY) are supported until Q4 2026. |
Important
From July 1, 2026, the Transactional category covers only Transactional Template messages. Plain text, file, and list messages can no longer be sent at the transactional rate and will be charged at the promotional rate if used. Promotional will stay the same.
What you send Rate category Available for Text only Transactional Transactional Text only (marketing) Promotional Promotional File/Document Transactional Transactional List (2-5 items) Transactional Transactional Image only Promotional Promotional Image + Text Promotional Promotional Image + Text + Button Promotional Promotional Text + Button Promotional Promotional Video Promotional Promotional Carousel (2-5 cards) Promotional Promotional OTP Templates OTP (dedicated rate) Transactional Country Specific Templates (RU/UA/BY) Transactional Transactional
Transactional
What are transactional Messages?
Transactional messages are essential business communications that provide important information to your users, such as order confirmations, shipping updates, and OTP codes. From July 1, 2026, all transactional messages must use the pre-approved Transactional Template format. See Transactional template messages for details.
Promotional
What are promotional messages?
Promotional messages are marketing and commercial communications designed to engage users, drive sales, and build brand awareness. These messages include rich media, interactive elements, and visual content.
What you can send as promotional:
- Text: Simple text notifications without images or buttons
- Images: Standalone images (PNG, JPEG, JPG, GIF - max 200 MB)
- Image + Text: Visual content with description
- Image + Text + Button: Rich cards with call-to-action
- Text + Button: Simple call-to-action messages
- Video: Video content (MP4 only, max 200 MB) with or without text/button
- Carousels: 2-5 swipeable cards with images and buttons
Special categories
OTP (One-Time Password) Templates
What are OTP Templates?
OTP templates are pre-approved, ready-to-use templates specifically designed for sending verification codes and authentication messages. Available for transactional accounts. More about OTP templates
Deprecated: effective July 1, 2026
OTP template messages are deprecated and will no longer be supported after July 1, 2026. From that date, OTP and all other transactional messages must use the new Transactional template messages format, which includes a dedicated OTP category with an "Copy" button for recipients.
Contact your account manager to get your new templates set up ahead of the deadline.