Viber bot limitations you should know before you build

This guide is for businesses that have already decided to build a bot on Viber and want to know the real platform constraints first: whether you can identify a customer by phone number, what it actually costs per month, and how many messages you can send before hitting a wall. Knowing this before you design your conversation flow saves a rebuild later.

Most Viber bot guides, even the thorough ones, cover pricing well but skip a constraint that can be a dealbreaker for any business that runs on a CRM tied to phone numbers: the bot itself never sees that number.

Quick facts

• A Viber bot cannot automatically retrieve a customer's phone number. It only sees an internal subscriber ID.
• Bots created since February 5, 2024 pay a EUR 100 monthly maintenance fee. Older bots keep the previous commercial model.
• Messages a bot sends in response to the customer are free. Messages the bot sends on its own initiative are billed per destination country.
• You can send up to 100 messages to a single user in an hour without a reply from them, then further messages are blocked.
• A single message is capped at 1000 characters, and a carousel message supports up to 6 cards.

Why businesses still use Viber

A Viber bot for business makes sense wherever Viber already has an established user base, and the platform has long been used for broadcast style marketing messages alongside one-to-one support. For a business already present there, a bot means customers get answers without switching to another app.

The phone number problem most guides don't mention

The Viber Bot API identifies every user by an internal subscriber ID, not their phone number. There is no standard API call that hands you a customer's number just because they messaged your bot. If you want phone-number-based messaging into an existing customer database, that runs through a separate Viber product called Business Messages, offered through official partners, not through the standard Bot API that a no-code builder like MaviBot connects to.

In practice this means you cannot silently match a new Viber subscriber to an existing CRM record by phone number. If you need that link, you have to ask for the number directly in the conversation and store it yourself, the same way you would collect any other piece of customer data.

What a Viber bot actually costs

Viber bot pricing changed in 2024, and it's worth understanding before you commit. Since February 5, 2024, creating or connecting a Viber bot comes with a EUR 100 monthly maintenance fee, agreed to as part of Viber's commercial terms. Bots that were already set up and billed before that date continue under the previous model.

Within that monthly fee, not everything costs the same. A session that the customer starts, and any message your bot sends as a reply within that session, is free. A message your bot sends on its own initiative, without the customer prompting it, is billed per message, at a rate that depends on the destination country.

Budget for the monthly fee as a fixed cost, and treat proactive outreach as a variable cost on top of it, not as something bundled in for free.

Message and rate limits to design around

A single Viber message tops out at 1000 characters. A carousel message can show up to 6 cards, with each card image in JPG or PNG format, ideally sized around 696x600 pixels and kept under 500KB. The full request you send to the API also can't exceed 30KB in total size.

There's also a rate limit per user: up to 100 messages to a single person within an hour without a reply from them. Once they reply, that counter resets. Send more than that without a response and you'll get an error back instead of a delivered message, so a bot that fires off automated follow-ups needs to pace itself rather than assume every message goes through.

One more constraint that shapes the first interaction: the very first message to a new subscriber is limited to a single message until they respond, and that first message can only use keyboard buttons, not buttons embedded inside the message text. Plan your opening message as one self-contained step, not the first of several you send back to back.

Together these limits mean a Viber bot works best with short, focused messages and a conversation that waits for a reply before pushing more content, rather than one built around long product descriptions or rapid-fire automated sequences.

Connecting Viber to Mavibot

How you register depends on when you're setting up. Bots created before February 5, 2024 go through the Viber Partners portal (account name, username, category, language, and a few other details) to get a bot token. Bots created from that date onward go through Viber's commercial application process instead. Either way, the token gets pasted into MaviBot's Channels settings. The full walkthrough is in MaviBot's Viber integration docs.

Carousels in Mavibot aren't built through a drag-and-drop card editor. They're set up with a short Python snippet in the Calculator field, using a send_carousel() method that takes a title, description, image, and buttons for each card.

If you want to see how this looks in practice, try Mavibot for free and connect a Viber account to test it yourself.

Where Viber bots fit in practice

Broadcast and marketing campaigns. Viber has long been used for one-to-many promotional messages, and a bot can handle the replies and follow-up questions those campaigns generate.

E-commerce with a manual customer-linking step. A bot takes orders and answers product questions, but since it can't pull a phone number automatically, checkout still needs a short step where the customer provides contact details for delivery. The same order-taking flow used for WhatsApp restaurant bots applies here, just with that extra data-collection step added.

Appointment-based services. Salons, clinics, and similar businesses can let customers book directly in the chat, with the same manual detail-collection step covering anything the booking needs beyond what Viber exposes. See how this works for spa and salon booking built on the same underlying flow.

All three cases run into the same constraint, not three different ones. Broadcasting, ordering, and booking all work fine on Viber, they just need that one extra step to collect a phone number that other channels would have handed you automatically.

What to plan for before you start

Before committing to Viber, know that you won't get a customer's phone number automatically, you'll pay EUR 100 a month plus per-message fees for anything your bot sends unprompted, and both your messages and your send rate per user are capped.

None of this rules Viber out. It just means the conversation design and the budget both need to account for these limits from the start, instead of being adjusted after the bot is already live.

Frequently asked questions

Can a Viber bot get a customer's phone number automatically?

No. The Bot API identifies users by an internal subscriber ID, not their phone number. Phone-number-based messaging runs through a separate product called Business Messages, available through official partners.

How much does a Viber bot cost per month?

Bots created since February 5, 2024 pay a EUR 100 monthly maintenance fee. Older bots keep the previous commercial model. On top of that, proactive messages the bot sends are billed per destination country, while messages sent in reply to the customer are free.

What's the message rate limit on Viber?

Up to 100 messages to a single user within an hour without a reply from them. The count resets once the user responds.

Do I need to code to build a Viber bot with MaviBot?

No. It's configured through MaviBot's visual builder and Channels settings. Carousels use a short Python snippet in the Calculator field rather than full custom development.

Start with the limits, not around them

A Viber bot that's designed around these constraints from day one avoids the awkward mid-build discovery that a feature you assumed would work, doesn't.

Try MaviBot for free to see how the setup works before you commit to a paid Viber bot.