Proton Calendar
Encrypted calendar included with every Proton account.
- Swiss CompanyThe operating company is headquartered and legally incorporated in Switzerland.
- Swiss OwnedThe ultimate controlling owner is Swiss (Swiss persons, companies, foundations or public bodies).
- Swiss Data OptionSwiss hosting is available as an option or for part of the service, but is not the default for everything.
- Free PlanA permanently free plan is available (not just a trial).
proton.me
Overview
Proton Calendar is a calendar service included with every Proton account. Event titles, descriptions, locations and participant lists are end-to-end encrypted on the user’s device. Start and end times, time zones, recurrence rules and alarm times are signed but not end-to-end encrypted, because Proton’s servers need to read them. Invitations received from other calendar providers arrive unencrypted and are encrypted by the server on receipt.
The calendar is available on the web, as iOS and Android apps and in Proton’s desktop apps for Windows, macOS and Linux (beta). It is not sold separately: the free plan includes a limited number of personal calendars, and Mail Plus and Proton’s bundled and business plans include more.
Proton states that calendar data is kept on Proton-owned servers in Switzerland, Germany or Norway. Since 2025 the company has shifted infrastructure away from Switzerland because of a proposed revision of the Swiss surveillance ordinance, while the contracting entity remains Proton AG under Swiss law.
Why it may be a Swiss alternative
Proton Calendar is operated by Proton AG, which is headquartered in Plan-les-Ouates, Geneva. Swiss-headquartered, Swiss-owned company; product developed (wholly or largely) in Switzerland.
Swiss hosting is available for part of the service or as an option — check the hosting details below before relying on it.
May replace
- Google CalendarGoogle LLC · US
- OutlookMicrosoft Corporation · USCovers the calendar part of Outlook; email is provided separately by Proton Mail.
Foreign products with overlapping functionality. An alternative is not necessarily a one-to-one replacement.
Swiss footprint
Five independent questions. A Swiss company is not automatically Swiss-hosted — and vice versa. How the footprint is assessed
Swiss native. Swiss-headquartered, Swiss-owned company; product developed (wholly or largely) in Switzerland.
- HeadquartersIs the operating company headquartered in Switzerland?
- Plan-les-Ouates, Geneva (GE), SwitzerlandVerified[1]
- Legal jurisdiction
- OwnershipIs the company ultimately Swiss-owned?
- Yes — Proton Foundation (Fondation Proton) · SwitzerlandVendor claim[4]
Proton states that the non-profit Proton Foundation is the primary shareholder of Proton AG; since June 2024 it has been the largest voting shareholder, endowed with shares donated by co-founders Andy Yen and Jason Stockman and first employee Dingchao Lu. The foundation is registered in Plan-les-Ouates (Fondation Proton, CHE-418.863.304). Employees hold most of the remaining shares; smaller stakes are held by the Geneva non-profit FONGIT and by Proton users. Proton says it has no venture capital investors. Exact percentages are not published.
- DevelopmentIs the product developed in Switzerland?
- PartlyInferred[2]
Developed by Proton AG, headquartered near Geneva. Proton's privacy policy also lists subsidiaries in North Macedonia and Taiwan as processors, and Proton runs an R&D office in Vilnius. Proton does not publish how development work is split between locations.
- HostingIs customer data hosted in Switzerland?
- Partly — Switzerland, Germany and NorwayVendor claim[1]
Proton's Calendar privacy policy states that data is stored encrypted on Proton servers located exclusively in Switzerland, Germany or Norway, without a per-country breakdown. Since July 2025 Proton has been moving the majority of its physical infrastructure out of Switzerland, citing the proposed revision of the Swiss surveillance ordinance (VÜPF/OSCPT); its August 2026 incident report describes core databases split between Frankfurt and Zurich.
- InfrastructureIs the hosting infrastructure operated by a Swiss-owned provider?
- Yes — Proton AG (Proton-owned servers in third-party data centres) · SwitzerlandVendor claim[6]
Proton says it owns its server hardware. According to a watson.ch report (August 2026) it rents secured space from data-centre operators it does not name, rather than running its own data centres in Switzerland, Germany or Norway.
Features & platforms
- Platforms
- Deployment
- Made for
- Interface languages
Privacy & security
- End-to-end encryption
- Partly
- Encryption at rest
- Yes
- Encryption in transit
- Yes
- Multi-factor authentication
- Yes
- Not verified
- Single sign-on (SAML/OIDC), SCIM provisioning, Public API and Data export
- Certifications
Pricing
Paid plans fromUSD 4.99 / monthMail Plus (includes Calendar), billed monthly; CHF and EUR prices also offered
- Pricing model
- Freemium
- Free plan
- Yes
- Free trial
- Unknown / not verified
- Enterprise plan
- Yes
- Billing in CHF
- Yes
Prices checked 15 Oct 2026. Always confirm on the vendor’s site. Pricing page ↗
Open source
- Open source
- PartlyVerified[10]
The web client (in the ProtonMail/WebClients repository) and the Android app are published under GPL-3.0; the server side is not published.
- Licence
- GPL-3.0 · OSI-approved licence
- Source code
- github.com/ProtonMail/WebClients
- GitHub
- 5'636 stars
- 731 forks
- GPL-3.0
- TypeScript
- last commit
Statistics from GitHub, fetched 15 Oct 2026.
Company
Company based in Plan-les-Ouates near Geneva that develops encrypted email, calendar, cloud storage, password manager, VPN and AI assistant services. Its primary shareholder is the non-profit Proton Foundation.
More from Proton
- Lumo — AI Assistants
- Proton Drive — Cloud Storage
- Proton Mail — Email
- Proton Pass — Password Managers
- Proton VPN — VPN
Similar Swiss products
Email hosting with calendar and contacts, for free addresses or your own domain.
Swiss native
- Hosted in Switzerland
- Free Plan
EmailFreemiumCollaboration suite with email, calendar, cloud storage, office editing, chat and video.
Swiss native
- Hosted in Switzerland
- Free Plan
Office SuitesFreemiumEncrypted email with end-to-end encryption between Proton users.
Swiss native
- Swiss Data Option
- Free Plan
EmailFreemium
Sources & verification
Every claim on this page is marked as verified, vendor claim or inferred. Unknown means we could not confirm it — not that the answer is “no”.
- Verified Confirmed by an independent or official source such as the commercial register.
- Vendor claim Stated by the vendor in its own documentation, website or legal terms.
- Inferred Derived by the editors from indirect evidence — see the note.
- [1]
- [2]
- [3]
- [4]
- [5]
- [6]
- [7]
- [8]
- [9]
- [10]
- [11]
Proton AG
- [1]
- [2]
- [3]
- [4]
- [5]
- [6]