Proton Mail vs Posteo

Both Proton Mail and Posteo are European-built, GDPR-compliant solutions in the email hosting space. This comparison breaks down their features, pricing, compliance posture, and data residency so you can make an informed choice for your team.

Quick Overview

Proton Mail

Headquarters: Geneva, CH
Pricing: Free / From €4/mo
Open Source: Yes

Posteo

Headquarters: Berlin, DE
Pricing: From €1/mo
Open Source: No

Key Differences

Proton Mail offers a free tier, while posteo starts at €1/month. This makes Proton Mail more accessible for individuals and small teams exploring their options before committing.
Proton Mail is open source, meaning you can audit the code, self-host, and avoid vendor lock-in. Posteo is proprietary, which often means a more polished out-of-the-box experience and dedicated support, but less flexibility for customisation.
Data residency differs: Proton Mail hosts data in Switzerland, Germany, while Posteo hosts in Germany. If your organisation requires data to stay in a specific EU country, this distinction matters for compliance.
Proton Mail holds ISO 27001 certification, providing third-party assurance of its security practices. Posteo does not currently hold these certifications, which may matter if your organisation requires them for vendor approval.
Posteo was founded in 2009, giving it a 5-year head start over Proton Mail (founded 2014). More time in market often means a larger user community and more mature integrations, though newer entrants may offer more modern architectures.
Each product has unique strengths: Proton Mail offers End-to-end encryption and Zero-access encryption, while Posteo provides 100% renewable energy powered and PGP and S/MIME encryption. Your choice depends on which capabilities matter most for your workflow.

Feature Comparison

Feature	Proton Mail	Posteo
Name	Proton Mail	Posteo
Pricing	Free / From €4/mo	From €1/mo
Free Tier
GDPR
ISO 27001
Open Source
Headquarters	Geneva, CH	Berlin, DE
Data Centers	CH, DE	DE
End-to-end encryption
Zero-access encryption
Custom domain support
PGP support
Bridge for desktop clients
Calendar
Cloud storage (Proton Drive)
VPN
Password manager
100% renewable energy powered
PGP and S/MIME encryption
Anonymous registration
Calendar and contacts (CalDAV/CardDAV)
Incoming mail encryption
Two-factor authentication
No ads or tracking
Cash payment option

Pricing Comparison

Proton Mail

Free / From €4/mo

freemium

Posteo

From €1/mo

subscription

Compliance Comparison

Proton Mail

GDPRISO 27001DPA

Posteo

GDPRDPA

Get Started

Try Proton Mail

Encrypted email from Switzerland

Visit Proton Mail

Try Posteo

Green and privacy-focused email provider

Visit Posteo

How to Choose

You need code transparency or self-hosting

Choose Proton Mail

You want a fully managed, turnkey solution

Choose Posteo

You're a startup or individual on a budget

Choose Proton Mail

Your procurement requires ISO 27001 certification

Choose Proton Mail

You need enterprise-grade support and stability

Choose Proton Mail

You prefer a nimble provider with personalised support

Choose Posteo

Proton Mail vs Posteo — FAQ

What is the main difference between Proton Mail and Posteo?

Both Proton Mail and Posteo are European email hosting solutions with full GDPR compliance. The key differences lie in their approach: Proton Mail is open source while Posteo is proprietary, and Proton Mail uses freemium pricing while Posteo uses subscription. Proton Mail is headquartered in Geneva, Switzerland, while Posteo is based in Berlin, Germany. Your choice should depend on your specific requirements for features, pricing, and data residency.

Which is more affordable, Proton Mail or Posteo?

Proton Mail offers a free tier, while posteo starts at €1/month. Pricing models differ (freemium vs. subscription), so compare based on your usage pattern rather than just the starting price.

Are both Proton Mail and Posteo GDPR compliant?

Yes. Both Proton Mail and Posteo are European companies that store data within the EU/EEA and offer Data Processing Agreements. Neither is subject to the US CLOUD Act or FISA surveillance. Additionally, Proton Mail holds ISO 27001 certification. For GDPR purposes, either option eliminates the legal risks associated with using US-based services.