The Sovereignty Imperative
Gartner expects EU sovereign cloud IaaS spending to nearly double in 2026, from $6.9 billion to $12.6 billion, and to reach $23.1 billion by 2027.

Two factors are driving this: regulation and geopolitics. GDPR, NIS2, DORA, and the EU Data Act have generated €7.1 billion in cumulative fines. And in July 2025, Microsoft told the French Senate under oath that it could not guarantee European data would stay out of US hands under the CLOUD Act.

The EU's Cloud and AI Development Act, proposed in June 2026, adds four assurance levels. At the top two, which cover sensitive public-sector and critical-infrastructure workloads, US-owned hyperscalers simply don't qualify. They still run more than 70% of the European market, but 61% of Western European CIOs now say geopolitics is pushing them toward local providers.

The Egress Problem Nobody Budgets For
The market has already started to move. The European Commission awarded a €180 million sovereign-cloud framework to four European providers, including STACKIT, Scaleway, and OVHcloud. The Dutch central government signed one with an EEA exit clause. De Nederlandsche Bank moved to Schwarz Digits, STACKIT's parent. And in November 2025, Schwarz Digits broke ground on an €11 billion, 200 MW data centre in Lübbenau.

What often gets missed is what happens once an organization is running across two clouds: moving data between them is expensive, and it's expensive on purpose.

Hyperscaler egress costs 5–10× what European providers charge: $0.05–$0.09/GB at volume, up to $0.12/GB on GCP's Premium tier, compared with rates that can be as much as 90% lower from EU providers. Hopsworks cut its cloud bill by 62% after moving from AWS to OVHcloud, most of it due to free egress.

The EU Data Act kills switching fees in January 2027, but day-to-day operational egress isn't covered. In a dual-cloud setup, enterprises pay it every time data crosses the line.

Solace as the Sovereign Data Backbone
This is where the Solace event mesh earns its place. Instead of copying whole datasets back and forth, Solace streams only what has changed, as events. In transactional workloads where only a small share of records change each cycle, this can cut cross-cloud transfer by an estimated 80–95%.

A few things that follow from that:

• Financial and government workloads on STACKIT keep a live, EU-sovereign system of record, fed by events from AWS or Azure, with no need to tear out what's already running.
• Topic subscriptions are selective, so each environment only receives the data it is legally allowed and operationally required to hold, which shrinks transfer volume and compliance exposure at once.
• It speaks AMQP, MQTT, REST, JMS, and Kafka-compatible APIs, so it bridges mismatched environments without a re-platforming project.
• Guaranteed delivery and replay give regulated industries the audit trail and resilience their rules require.
• The payoff is a predictable bill: organizations pay for small, discrete events, not full-dataset copies.

In the session, Hari will cover:

• The regulatory and geopolitical forces reshaping EU cloud in 2025–2026
• The real cost of cross-cloud data movement and how to model it
• The event-driven sovereign architecture pattern, with STACKIT as a reference implementation
• A cost-optimization framework spanning event payload sizing, topic design, and selective subscription strategies
• How the Solace event mesh enforces data-residency policy at the infrastructure layer, aligned with GDPR, DORA, NIS2, and the EU Data Act