EU Sovereignty Score
Self-hosted / open sourceMessagingHeadquarters: NL

Sylk: sovereignty score and 8 European alternatives

Sylk Suite is an open-source communications suite built on SIP and WebRTC. It consists of SylkServer, an extensible application server offering conferencing, messaging with offline storage and gateways to other protocols, among other things, and Sylk clients for macOS, Windows, Linux, iOS, Android and the web browser. According to the project, media are end-to-end encrypted with zRTP and messages with OpenPGP. Organisations use it to build their own real-time communications environment under their own domain.

Sylk is developed by AG Projects, a limited liability company registered in the Netherlands. The source code of SylkServer and the mobile client is released under the GPL version 3, so you can run the software on your own infrastructure and keep your data under your control. AG Projects also operates a browser client (webrtc.sipthor.net) and the public SIP2SIP service; according to its privacy policy, no user data is collected on purpose or shared, except push notifications via Apple and Google servers. Where these services are hosted is not stated. Development was co-funded through NLnet and the EU's NGI0 programme.

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Sovereignty score
94 / 1000 = high exposure
100 = sovereign
  • Jurisdiction SOV-2100
    Headquartered in the EU: European law applies
  • Data residency SOV-3100
    EU-only hosting
  • Cryptographic key sovereignty SOV-390
    Self-hostable: encryption keys under your own control
  • Freedom from lock-in SOV-680
    Open source: low switching costs
  • Source & runtime sovereignty SOV-4 · SOV-6100
    Source code auditable, forkable and self-hostable

SOV codes: the matching objective in the European Commission's Cloud Sovereignty Framework. Official source

How the score is calculated

Facts and evidence

Last checked October 16, 2026
Headquarters
NL (EU)Verified by hand
Data hosting
Self-hosted, e.g. in EU (your choice)Verified by hand
Open-source
YesVerified by hand
GDPR-compliant
YesVendor-stated
Category
Messaging
Type
Product
Website
sylkserver.com ↗

How we verify · Something wrong? Suggest a correction

Top EU-based & GDPR-compliant alternatives to Sylk

The European alternatives to Sylk come from our knowledge base of over 9,500 vendors. We only list vendors headquartered in the EU or the EEA; fully European-owned vendors rank before vendors with a foreign owner. For each alternative you see the country, the open-source status and a short description.

Score per alternative: 0 = high exposure, 100 = sovereign

36 European Messaging vendors are in the catalogue. View the whole category · Submit an alternative · View category on the map

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Why digital sovereignty matters with Sylk

Sylk is headquartered in NL and therefore falls under European law: the GDPR, NIS2 and the Data Act. No foreign legislation can compel access to your data.

Data is hosted exclusively in the EU, so Sylk scores best on data residency.

Sylk is open source. You can audit the source code, self-host the software and keep the encryption keys under your own control. Switching is easier because data and software are not tied to a single party.

What this means for your organisation depends on your whole stack and context. The free assessment weighs Sylk together with your other vendors and gives a total score, a heatmap and the main risk drivers.

Frequently asked questions

What is the best European alternative to Sylk?

It depends on your use case. Strong EU alternatives to Sylk include 360dialog, Balsio and Berty. On this page you can compare 8 EU alternatives by jurisdiction, data residency and open-source status.

Are there open-source alternatives to Sylk?

Yes. Open-source EU alternatives to Sylk include Berty, Conversations (XMPP), Delta Chat and Dino. These keep your data fully under your own control and let you self-host if you want to.

Is Sylk GDPR-compliant and where is the data hosted?

Sylk is headquartered in NL (EU) and hosts data in EU. It is also open-source, so you can self-host it. That makes Sylk an EU-sovereign choice in its own right; the EU alternatives on this page are comparable European tools.

Details and sources

Verified by handHeadquarters, owner, hosting locations and licence have been checked by us against public sources. Free of charge and for every vendor, not a paid label. Nothing in this knowledge base is taken over automatically. Last checked on October 16, 2026.

Sources

Public sources used in the latest check of this record.

Compliance evidence

The links below point to the vendor's own public documents. We only record what we found: a missing link means "not found publicly", not "not compliant".

No public compliance evidence has been recorded for this vendor yet. Do you know its DPA or subprocessor list? Something wrong? Suggest a correction

In the changelog

Earlier changes to this page, as listed in the public changelog.

Digital sovereignty in Messaging

Messaging: Personal messaging — chat, group conversations, media sharing. In this category the choice of vendor determines who has legal access to your data, where that data lives and how easily you can switch later.

Also in this category

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8 European alternatives to Sylk — GDPR-compliant & EU-hosted · EU Sovereignty Score