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Software · head to head

OneSignal vs Slack

O

OneSignal

Software

Customer engagement and messaging, without the complexity

From
Free
Rated
-
Full reviewWebsite
Slack logo

Slack

Software

Where work happens

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: OneSignal free plan email sends cap at 10,000 per month and web push is capped at 10,000 subscribers per send, per onesignal.com/pricing (Aug 2026); Slack 90-day message history limit on free plan results in important conversations disappearing

Where they differ

Only the attributes on which OneSignal and Slack actually diverge.

Attributes where OneSignal and Slack differ
AttributeOneSignalSlack
Pricing modelfreemiumUnknown
PlatformsWebWeb, iOS, Android, macOS, Windows, Linux
FoundedUnknown2009

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

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 OneSignal

Nothing recorded that Slack does not also cover.

Only in Slack

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

What people use each for

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

OneSignal

No use cases recorded yet. See the OneSignal review.

Slack

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

Where each one falls short

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

OneSignal

  • Free plan email sends cap at 10,000 per month and web push is capped at 10,000 subscribers per send, per onesignal.com/pricing (Aug 2026)
  • Professional and Enterprise plans require custom annual contracts with no published rate, per onesignal.com; SMS/RCS messaging and dedicated IPs are gated behind the Professional tier

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

Pricing, plan by plan

OneSignal

Free

No published plan breakdown. See the OneSignal review.

Slack

Free

No published plan breakdown. See the Slack review.

Which should you pick?

Choose OneSignal if

  • You want to start without paying.
OneSignal review

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

Questions people ask

Is OneSignal or Slack better?
Neither clearly leads. OneSignal starts at Free and Slack at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, OneSignal or Slack?
OneSignal starts at Free and Slack at Free.
Does OneSignal or Slack run on more platforms?
OneSignal runs on Web. Slack runs on Web, iOS, Android, macOS, Windows, Linux.
Can I use OneSignal for free?
Both have a free tier, so you can try either at no cost before committing.
What can OneSignal do that Slack cannot?
Slack covers Channels, Direct messaging, Voice & video calls, Screen sharing.

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
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
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
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
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Related pages

More on OneSignal

More on Slack

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