SilentSuite
Open-source, zero-knowledge calendar, contact, and task sync.
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Description
Open-source, zero-knowledge calendar, contact, and task sync. Plaintext stays off the server, and encryption keys stay on trusted devices.
About SilentSuite
What is SilentSuite?
SilentSuite is an open source, end-to-end encrypted sync platform for calendars, contacts, and tasks. It encrypts data on client devices before transmission so servers only store ciphertext.
What SilentSuite does
The system provides synchronized management of calendar events, task lists, and address books across web, Android, and desktop applications. Utilizing the Etebase protocol with XChaCha20-Poly1305 and Argon2id encryption, all records are encrypted on trusted hardware before being uploaded to sync infrastructure. A desktop bridge connects standard CalDAV and CardDAV clients including Thunderbird, Apple Calendar, and Outlook. Users can export data at any time in ICS, VCF, and ZIP archive formats. SilentSuite is offered as a self-hosted open source server under the AGPL license or as a hosted service with a 7-day card-free trial.
Who SilentSuite is for
It is built for people who want private calendar, contact, and task sync without exposing personal data to cloud servers.
How SilentSuite works
Client applications derive encryption keys on user devices from account credentials. Records are encrypted into ciphertext blobs prior to syncing with the server. A local bridge translates decrypted records for desktop clients, while keys remain on the device.
Key features
- End-to-end encrypted sync for calendars, task lists, and address books
- Encryption using the Etebase protocol with XChaCha20-Poly1305 and Argon2id
- Desktop bridge connecting apps like Thunderbird, Apple Calendar, and Apple Contacts
- Native Android client and web application supporting offline-first workflows
- Data portability with open export support for ICS, VCF, and ZIP formats
- Open source server released under the AGPL license with Docker deployment
- Hosted service providing sync across unlimited devices with locked pricing
- Flexible trial options including 7 days without a card or 30 days with a payment method
Pricing
As listed on silentsuite.io, checked 14 October 2026. Prices can change; see the site for current terms.
- Self-hosted: Free open-source server under AGPL with Docker one-line deploy
- Early Adopter: €3/month billed €36 annually for hosted sync across unlimited devices with a 7-day trial
Facts from silentsuite.io, checked 14 October 2026
Written from SilentSuite's own website (Homepage). The maker can claim this listing to edit it.
Categories
Frequently asked questions
What encryption standards does SilentSuite use?
SilentSuite uses the Etebase protocol with XChaCha20-Poly1305 for data encryption and Argon2id for key derivation.
Can desktop calendar and contact apps connect to SilentSuite?
Yes. A desktop bridge enables compatibility with CalDAV and CardDAV clients including Thunderbird, Apple Calendar, and Outlook.
What export formats are supported for backups?
Users can export calendars in ICS format, contacts in VCF format, or download all records as a ZIP archive.
Is SilentSuite available as open source software?
Yes. The server and web application are open source under the AGPL license and can be self-hosted with Docker.