Jonathan James is the founder of Perseus Technology. For over 25 years, he has worked at the intersection of technical investigations, security leadership, education, and hands-on delivery.
About Jonathan James
Security leadership grounded in technical depth.
A Swedish cybersecurity leader, forensic specialist, educator, and founder with more than 25 years of professional experience and over two decades in security and technical investigations.
His career spans penetration testing and digital forensics through to security architecture, executive roles, education, and product development. He is regularly engaged as an expert witness by lawyers, prosecutors, and Swedish district and appeals courts (tingsrätt and hovrätt).
What sets his profile apart is the rare combination of investigative precision and the ability to translate complex security challenges into clear, actionable decisions.
Selected roles
Roles and engagements most relevant to Perseus Technology and its direction.
2023 – present
Head of Cybersecurity Architecture, Nexer Cybersecurity AB
Senior architecture and advisory role bridging technical depth with business-level decision making.
2020 – 2023
Security Consultant, LEVEL Security Group
Internal security, forensics across iPhone, Android, and Windows, plus investigations into stalking, fraud, and incident response.
2019 – present
Instructor, Adversary Tactics and Techniques
Teaching focused on threat actors, intelligence methodology, nation-state behaviour, and modern cyber threats.
2011 – present
Founder, Areusecure AB
Security advisory: background checks, digital forensics, penetration testing, and secure development.
2014 – 2015
Chief Security Officer, Klarna AB
Global responsibility for IT security, information security, and physical security including incident handling.
2008 – 2013
Business Manager Security, Atea Sverige AB
Security testing, speaking, national competence leadership, and penetration testing of critical systems.
1999 – 2002
Founder and CEO, Securito AB
One of Sweden's early IT security companies, with clients including Microsoft and Boss Media.
1997 – 1999
Creator of Cassandra / Cassandra Gold
Early anti-trojan software for Windows, reaching tens of thousands of users.
Areas of expertise
A profile at the intersection of technical depth, forensic methodology, and senior-level judgement.
Digital forensics and technical investigations
Hands-on work across Android, iOS, Windows, macOS, and Linux. Support for law enforcement and complex private investigations. Regularly called as an expert witness in court proceedings.
Incident response under pressure
Leading serious incidents, risk assessments, and evidence-driven analysis in high-stakes environments.
Security architecture and executive communication
Translating technical realities into clear decision support without losing specialist depth.
Penetration testing, OSINT, and adversary understanding
Offensive methodology, open-source intelligence, and the study of threat actor behaviours and operating patterns.
Teaching and professional education
Lectures and seminars for Internetdagarna, Atea Bootcamp, Stockholm University, and the University of Bergen.
Advanced training
Security protection, behavioural analysis, reverse engineering, and SANS FOR610 (malware analysis).