Group Messaging with Transparency and Trust

Semaphor combines the best features of collaboration apps and encrypted messaging apps. Your team can work together through team messages, direct messages, and file sharing. Semaphor is secured by the power of private blockchain and end-to-end encryption.

Protect Your Confidential Communication and Your Everyday Work

Secure group messaging for your most sensitive data

The SpiderOak team needed a secure solution for group messaging and file sharing without the risks of email or off-the-shelf collaboration tools. We made Semaphor, group messaging with private blockchain encryption.

Now your company or team can protect your most important communication with the same No Knowledge application we use at SpiderOak.

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SpiderOak Semaphor Features


No Knowledge Collaboration

Our No Knowledge philosophy is the cornerstone of everything SpiderOak does. Your data in Semaphor is protected by Private Blockchain technology and end-to-end encryption. This means that all data is encrypted before it leaves your device and no data is visible or accessible to any SpiderOak employees. Only the members of your team have access to your data.

Mobile First Design

Semaphor 2.0 has been completely redesigned for usability and simplicity. Create teams and channels, send messages and files, all within an easy to use interface. Semaphor's mobile first design gives you full functionality no matter which of your devices you access it from.

Cross-Platform Support

Download and install Semaphor on all your computers and mobile devices. Supported platforms include Windows, macOS, iOS, and Android.

Peer Reviewed Code

With something as important as your security and data at stake, you need the ability to verify how our products work. You can download and review Semaphor's source code here.

View Semaphor's software licenses here.

View Semaphor's 3rd party licenses here.

Semaphor Support

Premium design backed by the world's best support team

Semaphor is free for teams of 5 or less. All teams include unlimited message and file retention, unlimited file sharing, a single file size limit of 2 GB, and unlimited channels and messages.

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Next Steps

To learn more about Semaphor and all of SpiderOak's secure communications, collaboration, back-up and storage products please contact us below: