Signal vs Slack
Side-by-side comparison of the Terms of Service and Privacy Policy of Signal and Slack.
Signal offers unusually strong privacy commitments and minimal data practices compared with many messaging services, including explicit no-sale language and end-to-end encryption. Its downsides are mostly standard legal-risk protections for the company: liability limits, California forum selection, unilateral policy changes, account termination discretion, and required phone-number registration.
Signal’s legal terms are notably privacy-forward for a messaging service: it says it does not sell or monetize personal data, uses end-to-end encryption, and stores limited account and technical information. The tradeoffs are standard but important: required phone-number signup, international data transfers, broad service disclaimers, a $100 liability cap, California-only dispute venue, unilateral updates, and the ability to suspend or terminate access at any time.
Points of interest
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positive ●●●●● termsNo data selling
Signal explicitly says it does not sell, rent, or monetize your personal data or content. That is a strong privacy commitment compared with many ad-supported services.
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positive ●●●●● privacyEnd-to-end encrypted content
Signal says it cannot access the contents of your messages or calls because they are end-to-end encrypted. In practice, this sharply limits what the company can read or disclose about your communications.
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negative ●●●●○ termsLiability capped at $100
If Signal harms you, its total contractual liability is capped at $100 to the extent allowed by law, and many categories of damages are excluded. This significantly limits practical remedies.
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positive ●●●●○ privacyMinimal server-side data
The policy says message history stays on your devices and that server-side technical data is limited to what is necessary to operate the service. This reduces the amount of personal information retained centrally.
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negative ●●●○○ termsPhone number required
You must sign up with a phone number and accept verification texts or calls. That creates an identity link many privacy-conscious users may prefer to avoid.
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negative ●●●○○ termsCalifornia courts only
Disputes must be brought in specified California courts under California law. This can make it harder or costlier for non-California or international users to pursue claims.
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negative ●●●○○ termsUnilateral changes and termination
Signal can update its terms and privacy policy, with continued use treated as acceptance, and it may suspend or terminate access at any time for any reason. Users have limited leverage if terms worsen or access is cut off.
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positive ●●●○○ termsYou keep ownership
Signal states that you own the information you submit through the service. Notably, the terms do not describe a broad content license letting Signal exploit user content.
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negative ●●○○○ privacyContact hashing uploads
If you use contact discovery, Signal may hash address-book data and send it to its servers to find other users. This is optional and privacy-protective by design, but still involves sharing derived contact data.
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negative ●●○○○ termsInternational data transfers
Signal says encrypted information and metadata may be transferred to the United States and other countries where it or its providers operate. Users outside those countries may face different legal protections.
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negative ●●○○○ termsNo emergency calling
Signal is not a substitute for emergency services. Relying on it in a crisis could be dangerous because it does not connect to police, fire, hospitals, or similar services.
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positive ●●○○○ privacyIn-app privacy controls
Users can manage personal information and enable extra protections like a Registration Lock PIN in the app settings. This is a useful transparency and account-security feature.
Documents
Slack provides meaningful privacy disclosures and several data-subject rights, but user control is limited in managed workspaces and data sharing/retention are broad. The posture is typical for business collaboration software, not especially user-friendly for individual privacy.
Slack’s legal terms are fairly standard for an enterprise messaging platform, but they are strongly workplace-controlled: employers or workspace owners govern most workspace data, settings, and many user rights. Slack collects substantial account, usage, device, cookie, location, and integration data, may share data with admins, service providers, affiliates, connected workspaces, and law enforcement, and transfers data internationally. The policy offers several user rights and California privacy options, but deletion and access for workspace content often require going through the customer controlling the workspace.
Points of interest
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negative ●●●●○ privacyBroad data collection
Slack collects account details, logs, device information, approximate location, cookies, imported contacts, third-party integration data, and audio/video metadata. That gives Slack a fairly detailed picture of how you and your device use the service.
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negative ●●●●○ privacyData shared with workspace admins
Owners and administrators may be able to access, modify, or restrict access to information, including profile details and workspace activity logs. In a workplace account, your employer may therefore have substantial visibility into your use of Slack.
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negative ●●●○○ privacyThird-party integrations can expose data
If a workspace enables third-party services, Slack may receive and share information with those providers, and those services run under their own policies. Users should assume integrated apps can expand where their data goes.
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negative ●●●○○ privacyLong retention of other data
Slack keeps non-customer personal data as long as necessary for support, legal compliance, disputes, and business purposes, including after account deactivation. That means some data can persist well after you stop using the service.
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negative ●●●○○ privacyInternational transfers
Slack transfers personal data outside your country, including to the United States and other countries. While it cites safeguards like Standard Contractual Clauses, cross-border transfers still increase jurisdictional exposure.
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positive ●●●○○ privacyDeletion and access rights
Slack says users may request access, correction, and deletion of personal information, and can use account settings tools where available. For workspace-controlled data, though, you may need to contact the customer/administrator.
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positive ●●●○○ privacyCalifornia opt-out tools
California users get CCPA/CPRA rights, including deletion, disclosure, and opting out of certain ad-related sharing. Slack also recognizes Global Privacy Control for cookie-based sharing signals.
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negative ●●○○○ privacyMarketing emails permitted
Slack uses personal data to send marketing emails and other promotional communications. You can control some of these messages, but marketing is still an express use of the service data.
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neutral ●●○○○ privacyWorkspace-controlled data
If you use Slack through an employer or other customer, that organization controls workspace settings and Customer Data. Practically, this means your message and file access rights may depend more on your workspace admin than on Slack itself.
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neutral ●○○○○ termsBinding agreement applies
The terms expressly say the Slack Terms are a binding agreement. This is standard, but it means use of the service is legally governed by incorporated agreements you should read carefully.
Documents
Comparison is based on each service's published Terms of Service and Privacy Policy. Read the source documents linked above before relying on any specific clause.