SnowDogg / development pipelineSCHEMATIC
Project SnowDogg
A local language model fine-tuned with security reference material and a dataset of more than 30,000 question-and-answer pairs.
JONATHAN HARTENSVELD
Offensive security.
Applied research.
I test web applications, APIs, and infrastructure, develop security tools, and research vulnerabilities.
Senior Penetration Testing Analyst
Penetration testing, automation, and vulnerability research.
Hudson Valley, New York
TECHNICAL FOCUS01 — 03
SECURITY TESTING / SYSTEMS / APPLIED AI
Web application, API, network, and server penetration testing.
WEB APPLICATIONS / APIS / INFRASTRUCTURENEW CREDENTIALGIAC Penetration TesterGPEN / 2026
01 / PROJECT PORTFOLIO
Selected projects.
Technical projects in security, applied AI, robotics, and infrastructure, with implementation notes and system diagrams.
GOOGLE GLASS EE2 / CUSTOM ANDROID APPGoogle Glass AI assistant
A custom Android application connecting Google Glass Enterprise Edition 2 to local AI models, with OCR, speech interfaces, and a 3D-printed mount.
Home network / logical topologySCHEMATIC
Segmented home network
A segmented home network using a UniFi Dream Machine Pro, Pi-hole DNS filtering, and a 4G LTE backup connection.
Trashy / detection to actionSCHEMATIC
Trashy: vision-guided robotics
A robotic arm controlled by custom software that uses YOLOv3 detections to identify desk trash and trigger pickup attempts.
Home lab / virtualization stackSCHEMATIC
Proxmox virtualization lab
An HP DL580 running Proxmox for Linux administration, guest operating system configuration, and virtual machine management.
JONATHAN HARTENSVELDOFFENSIVE SECURITY / VULNERABILITY RESEARCH
02 / PROFESSIONAL BACKGROUND
Security testing
and engineering.
I have 7+ years of experience across penetration testing, security operations, and information security architecture. Based in the Hudson Valley, I assess web applications, APIs, networks, and servers, and work with teams on remediation. I have personally identified hundreds of vulnerabilities through professional penetration testing, including findings rated critical, high, and medium.
My work includes tooling for cloud subdomain takeover detection and API scanning, Splunk research into authentication misconfigurations, and mentoring in dynamic application security testing (DAST).
I also conduct independent vulnerability research and present on security and emerging technologies. My personal projects apply local AI models, computer vision, and robotics to practical software and hardware prototypes.
PythonPowerShellBashJavaScript
View résumé EXPERIENCE TIMELINESoftware development, security operations, and penetration testing.
- 2011
Java development
Started programming in Java by developing Minecraft server plugins.
- 2018–19
Web administration & standards
Website administration, followed by a standards internship.
- 2020
Information security operations
B.S. in IT Management at Ramapo College and a role as an Information Security Analyst.
- 2023
Penetration testing
Moved into a Senior Penetration Testing Analyst role assessing applications, networks, and servers.
- 2024
Independent vulnerability research
Independent bug bounty research across public and private programs, focused on web applications, networks, and APIs.
03 / PROFESSIONAL CERTIFICATIONS
Security certifications.
LATEST CERTIFICATION2026
GPENGIAC Penetration Tester
Earned in 2026. Public credential verification is available through Credly.
Verify credential
Google Cloud
2024Professional Cloud Security Engineer
GIAC
2023Web Application Penetration Tester
CompTIA
2022Network+
GIAC
2021Security Essentials
Ramapo College
2020Web Development Certification
ADDITIONAL PROJECTS / 2025–2026
OSINT and robotics.
BTB OSINT
A web application scanning tool that uses open-source intelligence (OSINT) to investigate archived secrets and identify potential vulnerabilities. Developed with AI assistance.
Robot-enabled blackjack
A computer vision project using OpenCV and image training to control a six-axis robotic arm that plays blackjack against human players.
CONTACT
Professional inquiries.
Contact me about security research, technical collaboration, or speaking opportunities.