Broadcasts in Telegram and Viber bots: limits, costs, segmentation, and triggered messages
A broadcast helps a business when recipients understand why they received it and what they can do next. Sending everything to everyone quickly consumes attention and budget. Telegram and Viber differ in their limits and pricing: Telegram has a free broadcast speed limit and a paid acceleration option, while Viber distinguishes a 24-hour session following a user's message from a message initiated by the bot. Here is how to plan segments, triggers, costs, and performance checks.
Limits and costs: Telegram versus Viber
Telegram allows free bulk delivery at roughly 30 messages per second; Viber costs depend on the current contract, the recipient's country, and the message type.
| Factor | Telegram bot | Viber bot |
|---|---|---|
| Broadcast costs | Free within the standard limit; paid acceleration under Telegram's conditions | A contract may include a license fee and charges for delivered bot-initiated messages; check the current rate for each recipient country |
| Session messages | Standard Bot API rules | Viber describes the welcome message and replies within a 24-hour session after the user contacts the bot as free |
| Bulk delivery speed | About 30 messages per second | Depends on Viber's and the partner's terms |
| Acceleration | Paid broadcasts up to 1,000 messages per second at 0.1 Star per message above the free limit | Not applicable |
| Acceleration eligibility | Telegram specifies at least 100,000 Stars in balance and 100,000 monthly active users | Not applicable |
At a constant 30 messages per second, 50,000 recipients would take almost 28 minutes in theory. A real queue may run longer because of other limits and retries after a 429 error. Telegram recommends spreading large broadcasts over a longer period. In its 2025 commercial update, Viber describes 10,000 free bot-initiated messages per month, followed by per-delivery charges; its rate card separately lists a license fee and country-specific rates. Check your contract and the applicable version before budgeting. There is no universal price for every Viber bot.
Segmentation: who should receive what
Segmenting by acquisition source, behavior, and profile makes messages more relevant and can reduce Viber costs. Useful dimensions include acquisition source, platform, region or store, purchase history, and interest tags.
Examples from our projects:
- Veres: a separate deep link for each campaign automatically groups users. Each group has its own message sequence, and selected segments receive broadcasts announcing new YouTube videos. Content and broadcasts are managed centrally for Viber and Telegram. Read the Veres case study.
- KLEIBERIT: broadcasts filtered by country and user tags, with precise send times for Ukrainian and international versions of the bot. Read the KLEIBERIT case study.
- UA Made: one-off broadcasts segmented by platform and store, with personal variables, images, buttons, and scheduled delivery. Read the UA Made case study.
Triggered messages: reaching people at the right moment
A triggered message responds to a specific event, so it is easier to relate to a user need and measure separately from a bulk campaign.
Common triggers:
| Trigger | Example message |
|---|---|
| Birthday | A personal discount or bonus |
| Time since purchase | A reminder and a selection of new products |
| Bonus balance | “You have 300 points that expire next week” |
| Points added or redeemed | Confirmation of the balance change |
| Abandoned cart | A reminder for people who opted in |
| Service expiry | A renewal or return-visit reminder |
UA Made's loyalty program sends triggered messages for birthdays, time since purchase, bonus balance, and points earned or spent. We cover cart recovery and repeat sales in our article on online store automation.
Rules that protect your subscriber base
Every irrelevant broadcast increases the chance that a user blocks the bot and cannot easily be won back. Frequency and relevance matter more than reach.
- Consent. Send marketing messages only to people who agreed to receive them, and record when they consented.
- Easy opt-out. Include a “Stop promotions” button in every marketing message.
- Frequency. Set a weekly maximum of marketing messages per person.
- Timing. Account for the audience's time zone and active hours.
- Small-segment test. Start with 5–10% of the subscriber base before sending to the rest.
- Queue and error handling. Use a queue that retries after a 429 error so messages are not silently lost.
Broadcast metrics
Judge a broadcast by the actions it produces, not only the number of messages sent.
- For Telegram, accepted by the Bot API ÷ planned messages after the queue has finished measures technical API acceptance, not delivery to a person’s device. Track errors and retries separately.
- For Viber, delivered ÷ sent uses delivery confirmations; deduplicate by recipient and message so callbacks from multiple devices do not inflate the count.
- Tracked button clicks or visits through tagged links ÷ the corresponding cohort of API-accepted Telegram messages or uniquely delivered Viber messages indicates interest in the offer. Compare rates within the same platform and campaign.
- Target actions, such as a purchase, booking, or view: business outcome.
- Opt-outs and blocks following the broadcast: its cost to your audience.
- For Viber, cost per target action including message charges.
Our article on Telegram bots versus website bots discusses the choice of channel in more detail.
Conclusion
For Telegram, plan a delivery queue around the free limit and any paid acceleration you intend to use. For Viber, budget separately for session messages and bot-initiated messages under your contract. Segment subscribers, obtain consent, and make opt-out easy. Track target actions, costs, and opt-outs rather than sends alone.
Frequently asked questions
For bulk broadcasts, about 30 messages per second. Bots with more than 100,000 active users and at least 100,000 Stars in balance can enable paid broadcasts up to 1,000 messages per second.
Messages initiated by the bot may incur a delivery charge; rates depend on the country and contract. Viber describes free 24-hour sessions following a user's message and a monthly free allowance for bot-initiated messages in its updated terms. Check the current rate card before launching.
An automatic message sent in response to an event, such as a birthday, time since purchase, a change in bonus balance, or service expiry.
By acquisition source, using distinct campaign deep links, platform, region or store, purchase history, and interest tags.
Send only to people who opted in, cap the frequency, provide an easy opt-out, test a small segment first, and monitor opt-outs after every broadcast.
No. Having a CRM record does not mean someone subscribed to the bot or agreed to marketing messages. Check the contact source, subscription, consent, channel availability, and opt-out option before sending.
Sources
Telegram and Viber messaging implementation consultation
In 15 minutes with a BotLabs implementation specialist, discuss your audience, subscriptions, messaging consent, and campaign goal. Choose one segment and trigger for a pilot, identify budget inputs, and select a result metric.
One segment.
A first messaging trigger.
15 minutes with an implementation specialist: a segment, a trigger, and pilot budget inputs.
