EU sovereignScheduling & BookingHeadquarters: CH

Proton Calendar: sovereignty score and 8 European alternatives

Proton Calendar is the calendar app from Proton, the privacy-focused provider known for Proton Mail and Proton Drive. Users manage personal and work calendars, create events and invitations, and receive invitations from other calendars. Proton states that events are automatically end-to-end encrypted, including titles, descriptions, locations and invitees. The app is available for iOS, Android, macOS, Windows and Linux, and as a web app, with a separate offering for business teams.

Proton AG is incorporated in Switzerland, with its registered office in Plan-les-Ouates near Geneva. Its controlling shareholder is the Proton Foundation, a Swiss non-profit foundation, so no foreign parent is recorded. The calendar page states that user data is protected by Swiss privacy law but names no server location beyond Switzerland. For its business services Proton refers to GDPR compliance and offers a data processing agreement. The calendar page does not describe the app as open source or self-hostable. For a European organisation, Switzerland is a third country, and the encryption design is the provider's own claim, to be checked against its technical documentation.

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Sovereignty score

67 / 1000 = high exposure
100 = sovereign

Jurisdiction SOV-2100
Headquartered in Switzerland: Swiss law, recognised by the EU as adequate
Data residency SOV-380
Hosting in Switzerland only (recognised by the EU as adequate)
Cryptographic key sovereignty SOV-360
Key management with a European vendor
Freedom from lock-in SOV-640
Closed source: switching requires data migration
Source & runtime sovereignty SOV-4 · SOV-655
Closed source, runtime with the vendor

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 10, 2026

Headquarters	CH (EU)Verified by hand
Sovereignty model	Vendor-hosted (EU)Verified by hand
Data hosting	CHVerified by hand
Open-source	NoVerified by hand
GDPR-compliant	YesVendor-stated
Category	Scheduling & Booking
Type	Product
Website	proton.me ↗

How we verify · Something wrong? Suggest a correction

Top EU-based & GDPR-compliant alternatives to Proton Calendar

The European alternatives to Proton Calendar come from our knowledge base of over 6,800 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

39 European Scheduling & Booking 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 Proton Calendar

Proton Calendar is headquartered in Switzerland and falls under Swiss law, including the revised Swiss data protection act. Switzerland is not an EU member, but the European Commission recognises its level of data protection as adequate. Its Swiss headquarters does not by itself bring it under US legislation such as the CLOUD Act.

Proton Calendar hosts data in Switzerland only. Switzerland is not part of the EU or the EEA, so the GDPR does not apply there directly; the European Commission does recognise Swiss data protection as adequate, so personal data can go there without extra safeguards. Our model therefore scores it between EU hosting and hosting outside Europe. If you require strictly EU hosting, take this into account.

Proton Calendar is closed source and hosted by the vendor. The encryption keys and the runtime sit with the vendor and switching requires data migration. Ask about bring-your-own-key, export options and open standards.

What this means for your organisation depends on your whole stack and context. The free assessment weighs Proton Calendar 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 Proton Calendar?

It depends on your use case. Strong EU alternatives to Proton Calendar include Agendize, Billetto and Bokadirekt. On this page you can compare 8 EU alternatives by jurisdiction, data residency and open-source status.

Are there open-source alternatives to Proton Calendar?

Our list of EU alternatives to Proton Calendar is mostly commercial options. Browse the category on the map for open-source choices.

Is Proton Calendar GDPR-compliant and where is the data hosted?

Proton Calendar is headquartered in CH (EFTA) and hosts data in CH. That makes Proton Calendar 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 10, 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

Digital sovereignty in Scheduling & Booking

Scheduling & Booking: Appointment scheduling, online booking systems and calendar management. 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.

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