Stackable: Rebuilding big data infrastructure from the ground up

Founded in 2020 by open-source veterans Sönke Liebau and Lars Francke, the German startup, Stackable, is reimagining enterprise data platforms with a modular, Kubernetes-native architecture that prioritises data sovereignty, operational transparency, and open-source integrity.

What began as a “big data self-help group” for disillusioned Cloudera and Hortonworks users has evolved into a full-stack data platform with strategic backing from IONOS and a growing footprint across Europe, South Africa, and the UK. Here, Stackable’s co-founder and Chief Product Officer Liebau offers a walkthrough of the company’s origins, architecture, and ambitions.

Stackable’s genesis is rooted in the decline of the Hadoop ecosystem at that time. As Liebau recounts, the early promise of open-source big data was undermined by vendor lock-in, opaque licensing, and the eventual disappearance of community editions. Cloudera’s acquisition of Hortonworks in 2018 marked a turning point: the free versions of CDH and HDP were deprecated, leaving many enterprises stranded on unsupported infrastructure.

Stackable’s founders, then operating a boutique consultancy called OpenCore, were inundated with requests from clients seeking alternatives. “We started what I like to call a big data self-help group,” Liebau says, referencing a workshop hosted at Deutsche Bahn’s Silver Tower in Frankfurt. The group included 30 to 40 German enterprises, all grappling with the same dilemma: how to rebuild their data platforms without proprietary constraints.

The answer was Stackable, an infrastructure-as-code (IaC) platform built entirely on open-source components. Its architecture reflects the lessons of the Hadoop era: avoid monolithic distributions, embrace modularity, and ensure that every piece of the stack can be independently audited, replaced, or scaled.

At its core, Stackable is a curated orchestration layer for popular open-source data tools. The platform includes operators for:

• Data Ingestion: Apache NiFi, Apache Kafka
• Storage: Apache HDFS, Apache HBase
• Processing: Apache Spark, Apache Hive Metastore
• Analytics: Apache Druid, Trino
• Visualisation: Apache Superset
• Security: Open Policy Agent, certificate management via custom operators
• Orchestration: Apache Airflow.

All components are deployed via Kubernetes using custom resource definitions (CRDs) and YAML-based configuration files. Stackable’s operators are written in Rust and designed to be cloud-agnostic, supporting on-premises, hybrid, and public cloud deployments. The platform’s IaC approach enables reproducible environments, version control, and GitOps workflows, features that resonate strongly with enterprise IT teams.

As Liebau explains: “Everything is defined in code. You commit it to a repository, and it can be reproducibly rolled out to your environment.” This abstraction shields users from the complexity of configuring individual tools, while preserving the flexibility to customise integrations and business logic.

Stackable operates on an Open Core model. The community edition is fully open source under the OSL 3.0 license, while enterprise customers can opt for a dual-licensed subscription that includes:

• SLA-backed support (9/5 or 24/7)
• Vulnerability management and VEX statements
• Configuration templates and monitoring dashboards
• Integration with Red Hat OpenShift and other Kubernetes distributions.

Pricing is node-based, with a trust-based licensing model that avoids intrusive metering.

Stackable’s support model is lean, where all developers, including the founders, participate in the on-call rotation, ensuring that tickets are handled by engineers who understand the codebase. This direct engagement has helped Stackable win contracts with high-stakes clients, including the British Ministry of Defence and a German banking service provider that uses the platform for real-time fraud detection.

Partnerships and market reach

A pivotal moment in Stackable’s growth came in 2021, when IONOS acquired a 25.1% stake in the company. The partnership enables IONOS to offer Stackable as a managed service on its cloud platform, while providing Stackable with capital, infrastructure, and access to a broad customer base across the DACH region.

Stackable also benefits from shared services and operational support from b.telligent, a data consultancy founded by CEO Sebastian Amtage. This arrangement allowed Stackable to focus on product development during its early years, while gradually building out its own HR, finance, and sales functions.

Today, Stackable serves customers across Germany, the UK, South Africa, New Zealand, and Southeast Asia. While its roots are European, the platform’s cloud-native design and open licensing make it globally deployable.

Stackable’s emphasis on data sovereignty is more than a marketing slogan; it’s embedded in its architecture and compliance strategy. The platform is designed to support European regulatory frameworks, including:

• Cyber Resilience Act (CRA)
• Digital Operational Resilience Act (DORA)
• Software Bill of Materials (SBOM) via CycloneDX
• Vulnerability Exploitability Exchange (VEX) in CSAF format.

Stackable is a CVE Numbering Authority (CNA), enabling it to publish vulnerability records for its own products and upstream dependencies. It also participates in EU standardisation bodies, including ECMA International and the CRA Expert Group.

These credentials are increasingly important for customers in regulated industries. “We don’t just patch CVEs, we assess whether they’re exploitable in our context,” Liebau says. “That helps compliance teams filter out noise and focus on real risks.”

Stackable’s modularity lends itself to a wide range of use cases. The company has published case studies across sectors, including:

• Urban Data Platforms: City of Freiburg uses Stackable to aggregate and visualise public datasets
• Financial Services: A German banking provider uses Stackable for real-time fraud detection on payment streams
• Manufacturing: MARTIN GmbH deploys Stackable for performance monitoring in waste-to-energy systems
• Open Data: GBIF leverages Stackable for FAIR-compliant biodiversity data management
• Gaia-X Data Spaces: Stackable contributes to COSMIC-X and other sovereign data infrastructure projects.

Each deployment showcases Stackable’s ability to integrate diverse data sources, support real-time analytics, and maintain compliance with European data governance standards.

Stackable positions itself as a sovereign alternative to cloud-native data platforms such as Databricks, Snowflake, and AWS. While those vendors offer tightly integrated services, Stackable emphasises portability, transparency, and control.

Its closest analogues include Starburst (built on Trino), Confluent (Kafka-centric), and Cloudera (legacy Hadoop), but Stackable’s open-source purity and Kubernetes-native design set it apart. “We don’t do rocket science,” Liebau says. “We just build the boring stuff really well.”

That “boring stuff” includes certificate management, log aggregation, and operator lifecycle tooling, features that are often overlooked but critical for enterprise adoption. Stackable’s operators can be deployed on any Kubernetes distribution, including OpenShift, Tanzu, and Rancher, making it compatible with most enterprise environments.

Looking ahead, Stackable plans to extend its operator library with support for OpenSearch and metadata integration tools. The company is also exploring higher-level abstractions to simplify platform deployment and management.

Training and certification programs are in development, aimed at partners and customers who want to build internal expertise. Stackable’s partner model includes referral fees, reseller discounts, and subcontracting opportunities, with technical backup from Stackable’s core team.

The company’s long-term vision is to become the default open-source data platform for enterprises that value sovereignty, flexibility, and support. “We want to be the boring, reliable layer that lets customers focus on their business logic,” Liebau says.

Stackable may not have the flash of a Silicon Valley unicorn, but its approach is resonating with enterprises that have lived through the hype cycles of big data, cloud migration, and vendor consolidation. By combining open-source rigour with enterprise-grade support, Stackable offers a credible path toward sovereign, scalable, and sustainable data infrastructure.

In a market dominated by lock-in and opacity, Stackable’s commitment to openness and its ability to deliver make it a company worth watching.