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
Kivra
Dec 2025 – Present
Advisor to the CTO (Mar 2026 – Present)
(Interim) Director of Platform Engineering (Dec 2025 – Feb 2026)
- Supporting and developing the teams behind Kivra's technical foundation, spanning architecture, reliability, and developer experience on a BEAM-heavy stack with Erlang and Elixir at the core.
- Coaching engineering managers and tech leads, clarifying ownership, improving observability, and making everyday operations calmer and more predictable.
- Working closely with the CTO and engineering organization on platform strategy, infrastructure modernization, and key architectural decisions across backend and infrastructure domains (Erlang, Elixir, Go, Kubernetes, GCP).
Ignite Next
Mar 2026 – Present
Mentor
- Mentoring early-stage founders on technology strategy, architecture, and scaling. Supporting product clarity and technical decision-making.
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