Profile
Dr. Erik Stenman is a senior technology leader and systems architect with three decades of experience designing and operating distributed, fault-tolerant platforms in payments, fintech, and regulated infrastructure.
He has worked on the Erlang runtime since the late 1990s, holds a PhD on native code compilation for Erlang (the HiPE project), and wrote The BEAM Book, the technical reference on Erlang VM internals. As Klarna’s first CTO and one of the core architects of its payment platform, he helped grow the company from a small startup into a leading European payments business handling millions of transactions a day.
His recent work centres on bringing AI and agentic workflows into production systems in regulated industries, with attention to traceability, reliability, and governance. Through HappiHacking AB he advises and builds for companies running real-money platforms on the BEAM and adjacent stacks, where uptime, correctness, and auditability are non-negotiable.
He thrives in high-trust environments built on clarity, autonomy, and craftsmanship.
Experience
Kivra
Dec 2025 – Mar 2026
Advisor to the CTO (Mar 2026)
(Interim) Director of Platform Engineering (Dec 2025 – Feb 2026)
- Supported the teams behind Kivra's BEAM-heavy technical foundation, spanning architecture, reliability, and developer experience with Erlang and Elixir at the core.
- Coached engineering managers and tech leads on ownership, observability, and calmer day-to-day operations.
- Worked with the CTO on platform strategy, infrastructure modernisation, and key architectural decisions across Erlang, Elixir, Go, Kubernetes, and GCP.
HappiHacking AB
2014 – Present
Founder & Director of Engineering
- Designs AI-assisted development workflows and agentic architectures for production systems, with focus on traceability, governance, and integration with existing platforms.
- Leads consulting work on large-scale architecture, observability, and modernisation in regulated industries.
- Built event pipelines handling 1B+ daily transactions for Deutsche Telekom, GDPR-compliant end to end.
- Coaches architects and senior engineers at Redcare Pharmacy on scalable platform design and AI-driven workflow automation.
- Author of The BEAM Book, the technical reference on the Erlang virtual machine.
Redcare Pharmacy
2024 – Present
Coach for Architects / Platform Advisor
- Supports the build of a next-generation refund booking system with integrated AI-driven case handling and workflow automation.
- Guides architectural decisions on reliability, compliance, and maintainability under regulated constraints.
- Introduces design patterns for asynchronous workflows and end-to-end observability.
Scania / TRATON Group
2023 – 2024
Chief Engineer, Offboard Platform & Connectivity
- Drove a unified vehicle-to-cloud connectivity platform across TRATON brands.
- Standardised architecture for data exchange, diagnostics, and OTA updates.
- Delivered a secure, cloud-native framework supporting future smart-fleet services.
SambaNova Systems
2022
C++ Developer, AI Compiler Infrastructure
- Worked on AI compiler and runtime infrastructure, optimising ML workloads and integrating models into production systems.
- Contributed to the compiler and runtime toolchain, improving efficiency and integration with PyTorch and TensorFlow.
- Maintained CMake-based CI build systems for 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 and more efficient virtual machine for smart contracts.
- Built a BEAM-based blockchain optimised for verifiable, high-throughput transactions.
- Worked across consensus, state channels, and runtime safety with a small senior team.
Klarna Bank AB
2005 – 2014
Chief Technology Officer → Chief Scientist
- First CTO. Scaled engineering from 1 to 80 people and established Klarna's technical foundation.
- Architected and operated Klarna’s core payment infrastructure for 24/7 uptime as transaction volume grew by orders of magnitude.
- Built an Erlang-based payments platform that supported credit decisions, settlement, and fraud signals under tight regulatory constraints.
- Introduced principles of fault-tolerant, distributed architecture still in use across Klarna today.
- Worked closely with risk, compliance, and operations on incident response and post-incident learning.
Virtutech AB
2004 – 2005
Senior Developer
- Optimised the Simics full-system simulator, improving performance and accuracy for enterprise clients.
Selected Projects & Achievements
- Klarna Payments Platform, an Erlang-based core that scaled from prototype to multi-country production handling millions of daily transactions under financial regulation.
- IoT Data Platform (Deutsche Telekom), a GDPR-compliant event system handling 1B+ daily signals.
- Blockchain Core (æternity), a BEAM-based blockchain runtime engineered for verifiable, high-throughput transactions.
- AI-Driven Workflow Modernisation (Redcare Pharmacy), mentoring teams migrating legacy payment and case-handling flows into AI-assisted, service-oriented architectures.
- The BEAM Book, the technical reference on Erlang VM internals used by teams running real-money platforms on the BEAM worldwide.
Technical Focus
- Languages: Erlang, Elixir, Go, C / C++, Python, Rust
- Payments & Risk: core payment platforms, settlement flows, fraud signals, regulated operations
- AI Systems: LLM integration, agentic workflows, AI-assisted development, governance and traceability
- Infrastructure: Kubernetes, AWS, GCP, Terraform, Docker
- Practices: DevOps, observability, continuous delivery, incident response, post-mortems
- Domains: payments, fintech, regulated platforms, IoT, blockchain
Education
PhD, Computer Science, Uppsala University (1999 – 2002) Dissertation: Native code compilation and optimisation for Erlang (HiPE project).
Licentiate, Computer Science, Uppsala University (1996 – 1999) MSc, Computer Science, Uppsala University (1992 – 1996)
Postdoc, EPFL Lausanne (2003 – 2004), working with Martin Odersky on compiler technology and early Scala development.
Publications & Speaking
- Author: The BEAM Book, the technical reference on the Erlang virtual machine.
- Speaker: Code BEAM, Erlang Workshop, fintech architecture conferences.
- Mentor: advises engineering managers and architects on sustainable, high-trust team cultures.
Contact
happi@happihacking.se happihacking.com linkedin.com/in/happi