JONATHAN
JESSUP ©
I secure digital products with a blend of deep technical expertise and real-world attacker mindset. From web application hardening to full-scope penetration tests, I help you discover weaknesses before criminals do.
Why Work with Me
Tailored Security for Your Stack
Every business has a unique attack surface. I don’t sell generic checklists - I design security strategies that match your tech stack, infrastructure, and risk profile.
Attacker’s Mindset, Defender’s Discipline
Years of penetration testing experience allow me to think like an attacker while documenting and fixing issues like a meticulous defender. You get realistic tests and actionable remediation steps.
Clear Communication, No Fearmongering
Security jargon doesn’t help decision-makers. I translate complex findings into simple risks, business impact, and priority lists - so your team knows exactly what to fix and why.
Strengthening Systems, One Layer at a Time
SaaS Platform Penetration Test
2024
Full black-box and white-box testing for a multi-tenant SaaS product handling financial data. Identified critical authentication flaws and insecure direct object references before public launch.
Outcome: Zero critical issues at launch and successful external compliance audit.
E-Commerce Website Hardening
2023
Hardened a high-traffic online store processing thousands of transactions daily. Fixed payment-flow weaknesses, improved session handling, and configured security headers across the stack.
Outcome: Blocked automated card-testing attacks and reduced fraud-related incidents.
Security Program for a Growing Startup
2022
Built a practical security roadmap for a fast-moving startup – from secure SDLC practices and code review guidelines to incident response playbooks.
Outcome: Security embedded into development culture without slowing product delivery.
1. Discovery & Scoping
I start by understanding your product, architecture, compliance requirements, and risk tolerance. Together, we define realistic testing goals, boundaries, and success criteria.
2. Reconnaissance & Assessment
I map your attack surface, analyze technologies in use, and run both automated and manual checks to uncover vulnerabilities at every layer - from configuration issues to business logic flaws.
3. Exploitation & Validation
Potential weaknesses are verified through carefully controlled exploitation attempts. This validates real risk while protecting system stability and data integrity.
4. Reporting & Remediation Support
You receive a clear, prioritized report with proof-of-concepts, impact analysis, and step-by-step remediation guidance. I stay involved to help your team implement fixes and re-test where needed.
Secure Your Business from the Inside Out
Website & Web App Security
I secure web applications, APIs, and admin panels by uncovering vulnerabilities before attackers do.
OWASP-aligned security reviews
Configuration & access-control hardening
Continuous security for evolving products
Penetration Testing
Realistic, scenario-driven tests that simulate how attackers would target your systems - without the chaos of a real breach.
Black-box & white-box testing
Network, infrastructure, and API pentests
Clear, prioritized remediation reports
Security Consulting & Training
I help teams build security into their daily workflow instead of bolting it on at the end.
Secure development lifecycle (SDLC) design
Security architecture reviews
Workshops for developers & product teams
Discover My Security Journey
Hello, I’m Jonathan Jessup, a cybersecurity specialist dedicated to protecting websites and digital products from real-world threats. Over the years I’ve helped startups, agencies, and established companies understand their weak spots and transform them into strengths. My work is rooted in curiosity, ethical hacking principles, and a commitment to building systems that are safe by design – not merely patched after the fact.
Seeing the World Through a Different Lens
Outside of penetration tests and security audits, you’ll often find me behind a camera. Photography keeps my eye trained for detail, composition, and patterns – the same skills I rely on when analyzing complex systems for vulnerabilities. I document cities at night, quiet infrastructure, and the hidden geometry of everyday objects.
05+
Years of Experience
Helping businesses secure their websites, APIs, and internal tools.
80+
Assessments Completed
From focused web app reviews to full-scope penetration tests.
95%
Repeat Engagements
Clients who return for ongoing security work and retesting cycles.
My Client Stories
I collaborate with teams that care about doing things the right way – building products that are fast, usable, and secure. Here’s what some of them say after we’ve worked together.
“Jonathan helped us secure a critical release under a tight deadline. His report was detailed yet easy to follow, and our developers knew exactly what to fix first.”
Emily Carter
CTO, Fintrailr
“The penetration test revealed issues we never knew existed in our payment flow. Jonathan walked our team through every step and stayed involved until everything was safely resolved.”
Howard S.
Web-studio: weebly-to-shopify.com
