Leadership & Management
Leadership & Management
Profile
Dr. Erik Stenman is a senior technology leader and systems architect with three decades of experience building and scaling distributed, fault-tolerant systems. As Klarna’s first CTO, he helped transform a small invoicing startup into one of Europe’s leading fintech platforms. Through his company HappiHacking AB, Erik continues to architect large-scale infrastructure for fintech, telecom, and logistics — focusing on reliability, compliance, and performance.
He thrives in high-impact environments where clarity, autonomy, and craftsmanship drive innovation such as Klarna, Redcare, Deutche Telkom, and Scania/Traton.
Experience
HappiHacking AB
2014 – Present
Founder & Director of Engineering
- Leads consulting projects on large-scale system architecture, observability, and modernization.
- Built event pipelines handling 1 billion+ daily transactions for Deutsche Telekom.
- Coaches architects and senior engineers at Redcare Pharmacy on scalable platform design.
- Author of The BEAM Book, the definitive technical reference on Erlang VM internals.
Redcare Pharmacy
2024 – Present
Coach for Architects / Platform Advisor
- Supporting the build of a next-generation refund booking system with integrated AI case handling.
- Guiding architectural decisions on reliability, compliance, and maintainability.
- Introducing design patterns for asynchronous workflows and observability.
Scania / TRATON Group
2023 – 2024
Chief Engineer — Offboard Platform & Connectivity
- Drove a unified vehicle-to-cloud connectivity platform across TRATON brands.
- Standardized architecture for data exchange, diagnostics, and OTA updates.
- Delivered a secure, cloud-native framework enabling future smart-fleet innovation.
SambaNova Systems
2022 – 2022
C++ Developer — AI Compiler Infrastructure
- Analyzed and optimized machine learning models using MLIR and LLVM for next-generation AI hardware.
- Contributed to the compiler and runtime toolchain, improving efficiency and integration with PyTorch and TensorFlow.
- Worked on CMake-based CI build systems, ensuring cross-platform stability and performance.
- Technologies: Python, C++, LLVM, MLIR, PyTorch, TensorFlow, CMake.
æternity Foundation
2017 – 2019
Core Team Lead / Architect
- Designed and implemented FATE, a safer, more efficient virtual machine for smart contracts.
- Built a BEAM-based blockchain optimized for verifiable, high-throughput transactions.
Klarna Bank AB
2005 – 2014
Chief Technology Officer → Chief Scientist
- Scaled engineering from 1 → 80 people, establishing Klarna’s technical foundation.
- Architected and operated Klarna’s core payment infrastructure with 24/7 uptime.
- Introduced principles of fault-tolerant, distributed architecture still in use today.
Virtutech AB
2004 – 2005
Senior Developer
- Optimized the Simics full-system simulator, improving performance and accuracy for enterprise clients.
Key Projects & Achievements
- IoT Data Platform (Deutsche Telekom) — Designed a GDPR-compliant event system handling 1B+ daily signals.
- Blockchain Core Infrastructure (æternity) — Delivered a scalable BEAM-based blockchain runtime.
- Vehicle Connectivity Cloud (Scania / TRATON) — Unified platform for real-time fleet data and remote services.
- Fintech Modernization (Redcare Pharmacy) — Mentored teams migrating legacy payment flows to a service-oriented architecture.
Education
Ph.D. Computer Science, Uppsala University (1999 – 2002) Dissertation: Native Code Compilation and Optimization for Erlang (HiPE Project)
Licentiate in Computer Science, Uppsala University (1996 – 1999) M.Sc. Computer Science, Uppsala University (1992 – 1996)
Postdoc, EPFL Lausanne (2003 – 2004) — Worked with Martin Odersky on compiler technology and early Scala development.
Technical Focus
- Languages: Erlang, Elixir, Go, C/C++, Python, Rust
- Infrastructure: Kubernetes, AWS, GCP, Terraform, Docker
- Practices: DevOps, Observability, Continuous Delivery, Incident Response
- Domains: Fintech Payments, Digital Identity, IoT, Blockchain
- Specialties: Scalable Architectures, Fault Tolerance, Performance Optimization
Publications & Speaking
- Author: The BEAM Book — widely used reference for Erlang/Elixir VM internals.
- Speaker: Code BEAM, Erlang Workshop, Fintech Architecture Conferences.
- Mentor: Advises engineering managers on sustainable, high-trust team cultures.
Contact
📧 happi@happihacking.se 🌐 happihacking.com 🔗 linkedin.com/in/happi