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Head-to-head · Instant Messaging Software

Signal vs Slack

  • Updated Oct 2026
  • Both researched from official sources
  • 3 checks side by side
Higher score Signal #3 in Instant Messaging Software 9.2/10 Free plan Free plan✓ 0 of 2 features Visit Signal
Slack #6 in Instant Messaging Software 8.9/10 Free plan Free plan✓ 1 of 2 features Visit Slack

Signal leads on 1 check, Slack on 0, and 2 are even. Who comes out ahead on the 3 yes/no, price and count checks where we have data for both products. The editor score weighs everything else too.

Our verdict

  • Highest scoreSignal · 9.2/10
  • Lowest starting priceSignal · $1.99/mo
  • Free planboth
  • Most featuresSlack · 1 of 2

Signal scores higher on our rubric for instant messaging software: 9.2 against 8.9 out of 10; our editors rank them #3 and #6.

Signal is cheaper to start at $1.99/user/mo against $7.25/user/mo.

Signal is the better fit for privacy-focused everyday messaging. Slack is the better fit for teams coordinating work across connected tools.

  • Signal fits best

    Privacy-focused everyday messaging

  • Slack fits best

    Teams coordinating work across connected tools

Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. Bought places stand at the number bought; this page and our disclosure say so. Paying vendors may get a fuller, more detailed review from our editors, and that review can change their score. How we rank.

Side by side

Feature Signal 9.2/10 Visit ↗ Slack 8.9/10 Visit ↗
At a glance
Editor score 9.2 8.9
Ranking #3 in Instant Messaging Software #6 in Instant Messaging Software
Best for Privacy-focused everyday messaging Teams coordinating work across connected tools
Pricing model Free plan + paid Free plan + paid
Starting price $1.99/mo (best) $7.25/user/mo
Free plan ✓ ✓
Free trial — —
Deployment Desktop, Mobile Cloud, Desktop, Mobile
Platforms Windows, macOS, Linux, iOS, Android Web, Windows, macOS, Linux, iOS, Android
Features Signal 0/2 · Slack 1/2
End-to-end encryption Not checked yet Not checked yet
Guest access Not checked yet ✓ (best)
Specs
Message history Not checked yet Limited
Max group size Not checked yet Not checked yet
File size limit Not checked yet Not checked yet
Supported platforms Not checked yet Not checked yet
Our review
Pros
  • Signal-to-Signal messages and calls are end-to-end encrypted by default
  • Supports group chats of up to 1,000 members and group calls
  • Runs on mobile and desktop, with up to five linked devices
  • Public and private channels organize team conversations.
  • Slack Connect supports collaboration with external organizations.
  • Workflow Builder, huddles and AI summaries extend beyond messaging.
Cons
  • Secure Backups costs $1.99 per month for expanded media storage
  • Free backups cover recent media rather than a long media history
  • Messaging and calls are Signal-to-Signal over an internet connection
  • Free includes only 90 days of message history.
  • Free limits integrations to 10 apps and meetings to 1:1.
  • Pro and Business+ charge per user; Enterprise+ pricing is not shown here.
Our verdict

Signal is a nonprofit messaging app for individuals, families, groups, and organizations who want private everyday communication. Its core service is free, with end-to-end encryption on Signal-to-Signal messages and calls by default. It…

Read the review →

Slack brings workplace conversations into channels, direct messages and huddles, with files, app connections and workflow automation alongside them. It suits teams that want a shared place to coordinate work, whether they are small…

Read the review →
  1. SignalInstant Messaging Software 9.2Free plan
  2. SlackInstant Messaging Software 8.9Free plan

Strengths and trade-offs

  • Signal — where it wins

    • Signal-to-Signal messages and calls are end-to-end encrypted by default
    • Supports group chats of up to 1,000 members and group calls
    • Runs on mobile and desktop, with up to five linked devices

    Where it doesn't

    • Secure Backups costs $1.99 per month for expanded media storage
    • Free backups cover recent media rather than a long media history
    • Messaging and calls are Signal-to-Signal over an internet connection

  • Slack — where it wins

    • Public and private channels organize team conversations.
    • Slack Connect supports collaboration with external organizations.
    • Workflow Builder, huddles and AI summaries extend beyond messaging.

    Where it doesn't

    • Free includes only 90 days of message history.
    • Free limits integrations to 10 apps and meetings to 1:1.
    • Pro and Business+ charge per user; Enterprise+ pricing is not shown here.
  • Signal9.2/10 · Free plan

    Private, free messaging with encrypted calls and an optional paid media backup tier.

    Visit SignalFull verdict →
  • Slack8.9/10 · Free plan

    Channels, messaging, huddles and integrations connect workplace collaboration in one service.

    Visit SlackFull verdict →

More comparisons

All instant messaging software comparisons → · Full ranking →

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

Last updated · How we research and update