Slack vs Signal
Side-by-side comparison of features, pricing, ratings, and alternatives.
Slack is a messaging program designed specifically for the office, developed by Slack Technologies and now owned by Salesforce.
Signal is a nonprofit messaging app focused on privacy, with end-to-end encryption for all messages and calls by default and minimal metadata collection. It is the recommended choice for private communication.
Free tier with message history limits; paid plans from $7.25/user/month.
Free and open source, funded by donations.
- Excellent search and channel organization
- Huge app ecosystem
- Reliable and fast
- Great notification controls
- Best-in-class privacy
- E2E encryption by default
- Open source
- Free, no ads
- Free plan history limit is restrictive
- Can become noisy with too many channels
- Pricing adds up for large teams
- Requires phone number
- Smaller network than WhatsApp
- Fewer bells and whistles
What reviewers say
Slack Reviews
4.0 (3)Decent but has rough edges
Slack is solid overall, though it's not perfect. On the plus side, reliable and fast. That said, free plan history limit is restrictive, which held us back from rating it higher.
Solid choice
Been a daily user of Slack for a while now. Great notification controls. One minor gripe: pricing adds up for large teams, but it hasn't been a dealbreaker. Would recommend to anyone considering it.
Solid choice
Slack has quickly become part of our daily workflow. Huge app ecosystem. No major complaints so far. Would recommend to anyone considering it.
Signal Reviews
4.8 (4)Great messaging
Tried Signal recently. Free, no ads. Minor gripe: fewer bells and whistles. Would recommend.
Solid choice
We rolled out Signal last quarter. Free, no ads. No real complaints. Would recommend.
Solid choice
We rolled out Signal last quarter. Best-in-class privacy. No real complaints. Would recommend.
More alternatives & similar tools
Alternatives to Slack
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The Verdict
AI-generated from listing dataSignal offers best‑in‑class privacy for free, while Slack provides richer collaboration tools at a cost; choose based on whether privacy or workplace features matter more.
Key differences
- •Signal encrypts all communication end‑to‑end by default; Slack does not offer default E2E encryption.
- •Signal is free and open‑source; Slack uses a freemium model with paid tiers.
- •Signal’s network is limited to phone‑number users; Slack supports unlimited users across organizations.
- •Slack provides channel‑based organization, searchable history, and thousands of integrations; Signal has minimal extra features.
- •Signal runs as a desktop app on‑premise; Slack is a cloud SaaS service.
Pricing & value
Signal is completely free and donation‑funded; Slack’s paid plans start at $7.25 per user/month.
Ease of use / learning curve
Slack’s familiar channel UI and extensive help resources make onboarding easier than Signal’s minimal interface.
Features & depth
Slack offers organized channels, searchable history, huddles, workflow builder, and app ecosystem; Signal provides only core messaging and calls.
Integrations & ecosystem
Slack lists thousands of integrations (Google Calendar, GitHub, Zoom, Salesforce); Signal has no noted integrations.
Collaboration
Slack’s channel organization, notifications, and Slack Connect enable team collaboration; Signal is designed for private one‑to‑one or small group chats.
Scalability
Slack’s cloud SaaS model supports large enterprises; Signal’s smaller network and phone‑number requirement limit scale.
Support
Slack offers Help Center, email, and priority support; Signal only provides community support (no formal support listed).
Security & privacy
Signal provides default end‑to‑end encryption and minimal metadata collection; Slack does not guarantee E2E encryption.
Migration / lock‑in
Signal is open source with API, allowing data export; Slack’s SaaS model can create lock‑in, no migration details provided.
Choose Slack if…
Businesses or teams that need organized channels, integrations, and collaboration tools, and are willing to pay for them.
Choose Signal if…
Privacy‑focused individuals needing secure, free messaging without business collaboration features.
Common questions
Is Signal free to use?
Yes, Signal is free and open source, funded by donations.
Does Slack offer end‑to‑end encryption?
Not specified; Slack’s key features do not include default end‑to‑end encryption.
Can Slack integrate with other tools like GitHub or Zoom?
Yes, Slack supports thousands of integrations, including GitHub, Zoom, Google Calendar, and Salesforce.