Building Europe's
Digital Sovereignty
We believe that European enterprises deserve world-class productivity tools that do not compromise their data sovereignty, regulatory compliance, or strategic independence.
Why We Exist
"European enterprises deserve productivity tools that do not compromise their sovereignty. For too long, organizations have been forced to choose between best-in-class software and control over their own data."
UnionStack was founded on a simple principle: you should never have to send your data outside Europe to write a document, send an email, or host a video call. We build the full enterprise suite -- email, collaboration, security, and endpoint management -- entirely within EU borders, governed exclusively by EU law.
Our Story
In July 2020, the Court of Justice of the European Union invalidated the EU-US Privacy Shield in what became known as the Schrems II ruling. Overnight, thousands of European companies faced an uncomfortable truth: their most sensitive business data was subject to US surveillance laws, and there was no legal fix on the horizon.
Our founders -- a team of former enterprise IT leaders from Deutsche Telekom, SAP, and the European Commission -- saw this not just as a legal problem, but as a strategic vulnerability. European businesses needed a real alternative, not a compliance band-aid.
In 2021, they founded UnionStack in Berlin with a clear mission: build an enterprise productivity suite that is sovereign by design. Every line of code, every data center, every employee and subcontractor -- entirely European. No legal loopholes. No transatlantic data transfers. No compromises.
Our Values
Four principles guide every decision we make, from product design to hiring to how we run our data centers.
Sovereignty
Your data stays in Europe, governed by EU law alone. No CLOUD Act exposure, no foreign government access, no exceptions.
Security
End-to-end encryption, zero-trust architecture, and ISO 27001 certification. Security is not an add-on -- it is the foundation.
Simplicity
Enterprise software should not require a PhD to use. We design for clarity, ease of migration, and minimal admin overhead.
Sustainability
All our data centers run on 100% renewable energy. We publish annual sustainability reports and are committed to carbon-neutral operations.
Leadership Team
Seasoned enterprise technology leaders united by a shared belief in Europe's digital sovereignty.
Dr. Marcus Hoffmann
Co-Founder & CEO
Former VP of Cloud Infrastructure at Deutsche Telekom. 20 years in enterprise IT with a PhD in distributed systems from TU Munich.
Katrin Vogel
Co-Founder & CTO
Former Principal Engineer at SAP. Architect of large-scale collaboration platforms serving millions of users across Europe and Asia.
Pierre Dubois
Chief Product Officer
Former Senior Product Director at OVHcloud. Spent a decade building privacy-first products for the European public sector.
Dr. Lena Strand
Chief Security Officer
Former cybersecurity advisor to the European Commission. Led incident response teams at Ericsson and has published extensively on EU data protection.
Andreas Keller
Chief Revenue Officer
Former Managing Director of Enterprise Sales at Microsoft Germany. Brings 15 years of experience scaling SaaS across European markets.
Sofia Bergman
VP of Engineering
Former Tech Lead at Spotify. Built and scaled distributed systems serving hundreds of millions of requests per day with a focus on reliability and privacy.
Our Data Centers
Six strategically located data centers across the EU, each certified to the highest security and compliance standards. Your data never leaves European soil.
Frankfurt I
DEPrimary EU hub. Tier IV facility with ISO 27001 and SOC 2 Type II certification. Houses core email and collaboration infrastructure.
Frankfurt II
DEDisaster recovery and failover site. Full redundancy with synchronous replication from Frankfurt I, ensuring zero data loss.
Amsterdam
NLWestern Europe edge node. Optimized for low-latency video conferencing and real-time collaboration across Benelux and the UK.
Paris
FRSecNumCloud-qualified facility serving French government and enterprise customers. Meets the strictest French sovereignty requirements.
Stockholm
SENordic hub powered by 100% hydroelectric energy. Serves Scandinavian enterprises with ultra-low latency and green credentials.
Zurich
CHSwiss data protection laws combined with EU adequacy. Ideal for financial services and pharma customers requiring additional jurisdictional separation.
No US Jurisdiction
All facilities are owned and operated by European entities with no US parent company, ensuring zero CLOUD Act exposure.
Encryption at Rest & in Transit
AES-256 encryption for data at rest and TLS 1.3 for all data in transit. Enterprise customers can bring their own encryption keys.
Annual Sovereignty Audits
Independent third-party audits verify our data residency claims annually. Full reports are available to Enterprise customers.
Our Journey
From a founding team of six to a European enterprise platform serving millions.
Company Founded
UnionStack is established in Berlin by six former enterprise IT leaders. Seed funding of EUR 4M secured from European deep-tech investors.
Company Founded
UnionStack is established in Berlin by six former enterprise IT leaders. Seed funding of EUR 4M secured from European deep-tech investors.
First Product Launch
UnionStack Mail and UnionStack Docs launch publicly. First 100 enterprise customers onboarded within three months, including two DAX-listed companies.
ISO 27001 Certification
Achieved ISO 27001 certification across all operations. Launched the full collaboration suite including video conferencing and endpoint management. Series A of EUR 25M raised.
ISO 27001 Certification
Achieved ISO 27001 certification across all operations. Launched the full collaboration suite including video conferencing and endpoint management. Series A of EUR 25M raised.
1,000th Enterprise Customer
Crossed 1,000 enterprise customers and 1.5M active users. Opened data centers in Stockholm and Zurich. Named a "Cool Vendor" by Gartner in European Cloud.
Series B Funding
Raised EUR 80M in Series B led by top European growth equity funds. Expanding into Southern and Eastern European markets. Team surpasses 400 employees across eight EU countries.
Series B Funding
Raised EUR 80M in Series B led by top European growth equity funds. Expanding into Southern and Eastern European markets. Team surpasses 400 employees across eight EU countries.
Ready to Take Back Control of Your Data?
Join hundreds of European enterprises that have already made the switch. Get a personalized demo and see how UnionStack can replace Microsoft 365 — with true sovereignty.