Is Slack or Viber better?

Neither clearly leads. Slack starts at Free and Viber at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.

Which is cheaper, Slack or Viber?

Slack starts at Free and Viber at Free.

Does Slack or Viber run on more platforms?

Slack runs on Web, iOS, Android, macOS, Windows, Linux. Viber runs on iOS, Android, Windows, macOS, Web.

Can I use Slack for free?

Both have a free tier, so you can try either at no cost before committing.

What is Slack best used for?

Slack is most often used for team communication, project coordination, customer support, remote work. Of those, team communication and project coordination are not what Viber is typically brought in for.

What can Slack do that Viber cannot?

Slack covers Channels, Direct messaging, Voice & video calls, Screen sharing. Viber covers End to end encryption, Communities, Viber Business Messages, Free calling.

Communication · head to head

Slack vs Viber

Slack

Communication

Where work happens

From: Free
Rated: -

Full review Website

Viber

Communication

Messaging app with its strongest user base in Eastern Europe and the Philippines, owned by Japans Rakuten

From: Free
Rated: -

Full review Website

The short version

Each has a real cost: Slack 90-day message history limit on free plan results in important conversations disappearing; Viber viber has limited relevance outside its strong regions, so building a communication strategy around it in North America or most of Western Europe reaches almost nobody.
They diverge on capability: Slack covers Channels, Viber covers End to end encryption.
Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Slack and Viber actually diverge.

Attributes where Slack and Viber differ
Attribute	Slack	Viber
Pricing model	Unknown	Free to download, paid business messaging and out calls to landlines and mobiles
Platforms	Web, iOS, Android, macOS, Windows, Linux	iOS, Android, Windows, macOS, Web
Founded	2009	Unknown

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Communication).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Slack

Channels
Direct messaging
Voice & video calls
Screen sharing
File sharing
Search
Workflow builder
Slack Connect

Only in Viber

End to end encryption
Communities
Viber Business Messages
Free calling
Self-destructing messages
Rakuten integration

What people use each for

The jobs each tool is most often brought in to do.

Slack

Team communicationnot Viber
Project coordinationnot Viber
Customer supportnot Viber
Remote worknot Viber
Cross-functional collaborationnot Viber

Viber

A business communicating with customers in Eastern Europe or the Philippines where Viber, not WhatsApp, is the default appnot Slack
An individual making cheap international calls to family in a Viber-strong market before switching entirely to data callingnot Slack
A brand running a Community channel to reach an established Viber audience in a specific countrynot Slack
Someone wanting end to end encrypted chat on by default without configuring anythingnot Slack

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Slack

90-day message history limit on free plan results in important conversations disappearing
Per-user pricing becomes expensive quickly for larger teams
Notification overload with 78% of employees feeling overwhelmed by notifications
Mobile app performance issues including lag and slow syncing
Huddles limited to 50 people and cannot be recorded
Requires dedicated video conferencing service for formal meetings and webinars

Viber

Viber has limited relevance outside its strong regions, so building a communication strategy around it in North America or most of Western Europe reaches almost nobody.
Ownership by Rakuten ties the app to a commerce and points ecosystem, and account data can be linked to Rakuten services in markets where that integration is active.
Business Messages pricing is metered per message, so a company sending high volumes of promotional content can find costs rise quickly compared with a flat fee model.
Viber has lost share even in some of its historically strong markets to Telegram and WhatsApp, so its regional dominance is not guaranteed to persist.
The desktop client depends on the phone app remaining active and connected, which is a limitation for anyone wanting a fully independent desktop messenger.

Pricing, plan by plan

Slack

Free

No published plan breakdown. See the Slack review.

Viber

Free

ViberFree
- Free messaging and calling between Viber users
- Viber Out charges per minute for calls to non-Viber phone numbers
- Business Messages priced per message sent to businesses on a metered basis

Which should you pick?

Choose Slack if

You need channels.
You want to start without paying.
You work on Web, iOS, Android, macOS, Windows, Linux.
You also want direct messaging.

Slack review

Choose Viber if

You need end to end encryption.
You want to start without paying.
You work on iOS, Android, Windows, macOS, Web.
You also want communities.

Viber review

Questions people ask

Is Slack or Viber better?: Neither clearly leads. Slack starts at Free and Viber at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Slack or Viber?: Slack starts at Free and Viber at Free.
Does Slack or Viber run on more platforms?: Slack runs on Web, iOS, Android, macOS, Windows, Linux. Viber runs on iOS, Android, Windows, macOS, Web.
Can I use Slack for free?: Both have a free tier, so you can try either at no cost before committing.
What is Slack best used for?: Slack is most often used for team communication, project coordination, customer support, remote work. Of those, team communication and project coordination are not what Viber is typically brought in for.
What can Slack do that Viber cannot?: Slack covers Channels, Direct messaging, Voice & video calls, Screen sharing. Viber covers End to end encryption, Communities, Viber Business Messages, Free calling.

Answered from the vendors’ own pages

Slack: Does Slack have a free plan?

Yes, Slack offers a free plan indefinitely with no credit card required. Free users get 90-day message history, up to 10 app integrations, and 1:1 huddles.

Source

Viber: Is Viber end to end encrypted?

Yes, by default for one-to-one and group chats, unlike Telegram where it is opt-in for secret chats only.

Slack: What are Slack's pricing plans?

Slack offers Free, Pro ($7.25/user/month with annual billing), Business+ ($12.50/user/month), and Enterprise Grid (custom pricing). Monthly billing costs approximately 20% more than annual.

Source

Viber: Is Viber popular in the United States?

No, it has a comparatively small footprint there. Its real strength is in specific markets including parts of Eastern Europe and the Philippines.

Slack: Does Slack support offline use?

Slack is a cloud-based platform and does not support robust offline work. Internet connectivity is required to access messages and collaborate.

Source

Viber: Who owns Viber?

Rakuten Group, a Japanese e-commerce and internet services company, which bought Viber in 2014.

Slack: What integrations does Slack support?

Slack integrates with 43+ apps on average per team, including Google Drive, ChatGPT, Vercel, Asana, GitHub, and many others through their app marketplace.

Source

Slack vs Viber

Slack

Viber

The short version

Where they differ

What each one covers

Only in Slack

Only in Viber

What people use each for

Slack

Viber

Where each one falls short

Slack

Viber

Pricing, plan by plan

Slack

Viber

Which should you pick?

Choose Slack if

Choose Viber if

Questions people ask

Answered from the vendors’ own pages

Related pages

More on Slack

More on Viber

Keep looking

Other head to heads