Guillaume Castagnino


Engineer graduated from IIE.
I’ve spent my entire career in software development, and over a decade specifically in cybersecurity software, from development to product management, and from legacy infrastructures to cloud ecosystems.
I am currently looking for a Product Owner position focused on technical and cybersecurity topics that bring meaning to its customers.


VulnIT — DenyAll — Rohde-Schwarz Cybersecurity — UBIKA

Paris area, FR

Over time, I saw 4 different companies with this employer.
VulnIT was a small company providing a vulnerability scanner and assessment tool. It was bought by DenyAll, a Web Application Firewall editor, to complete its portfolio. Then DenyAll saw 2 shareholders changes.

Product Manager for “Cloud Protector” @ UBIKA

March 2022 – present

  • Managing “Cloud Protector”, the SaaS flavor of the Web Application Firewall
  • Managing the relation with “Cloud Protector” providers
  • Leading in collaboration with the CTO the reboot of “Cloud Protector” using a Lean approach, with enhanced portfolio synergy
  • Planning product launch and sales model for the new security modules of the “Cloud Protector” reboot
  • Webinars preparation and presentation
  • Product roadmap presentation in company summit and conducting workshops with customers working groups
  • Product roadmap presentation in one-to-one with customers
  • Commercial partnership study in collaboration with head of PM
  • PO
  • PM
  • Kanban
  • Lean
  • Jira
  • Confluence

Product Owner for “Cloud Protector” @ RSCS

Jan 2018 – March 2022

  • Managing “Cloud Protector”, the SaaS flavor of the Web Application Firewall, in collaboration with the head of PM
  • Optimizing the COGS of “Cloud Protector“, including platform migration
  • Working on the MVP design of a new product targeted towards DevSecOps teams
  • Acting as backup Ops on duty for “Cloud Protector”
  • PO
  • Scrum
  • Jira
  • Confluence

Senior Software Engineer @ DenyAll – RSCS

Jul 2012 – Jan 2018

  • Acting as PO for “Vulnerability Manager”
  • Building a platform for the Vulnerability Scanner delivered as SaaS (HA, load balancing, database redundancy…)
  • Development and maintenance on the “Vulnerability Manager”, in particular improve the website crawler, adapting to the growing use of async requests (SPA)
  • Development, refactoring and maintenance on the core of the Web Application Firewall
  • Development and maintenance of Cloud Protector, the SaaS version of the Web Application Firewall
  • Scrum organization
  • PO
  • Scrum
  • vCloud
  • C
  • Java
  • PHP
  • Python
  • Ansible
  • PostgreSQL
  • Vulnerability assessment
  • Network

Senior Software Engineer @ VulnIT

Feb 2011 – Jul 2012

  • VulnIT provides “Vulnerability Manager”, a vulnerability scanner historically as a bootable USB key
  • Redesign of the product architecture: moving from a Java/Swing monolith to a n-Tier architecture with a web UI
  • Deliver the product as a Virtual Machine image with an automated image build in CI
  • Create “agents” to deploy in various split networks and connect them to a central Vulnerability Manager
  • Virtualization
  • Network
  • Vulnerability assessment
  • Java
  • PHP
  • PostgreSQL

PepperWay SCOP ARL

Paris, FR

PepperWay was a web agency we founded with former Telecom Italia colleagues

Co-founder, CTO

Oct 2009 – Feb 2011

  • Building the web hosting cluster with sate of the art (at this time) HA: heartbeat, haproxy, nginx, DRBD, database redundancy
  • Building the mail hosting cluster (Postfix, Cyrus IMAP) with up to date antispam technologies deployed (DKIM, SPF) and HA (storage replication with DRBD)
  • Technical lead for customers projects, either e-commerce portal integration and customization (Prestashop) or custom built websites.
  • HA
  • Hosting
  • AntiSpam
  • PHP
  • PostgreSQL

Telecom Italia France “Alice” — Free SAS

Paris, FR

Telecom Italia France was an Internet provider (“Alice”) that was bought by Free. No employer change.

Software Engineer @ Free SAS

Aug 2008 – Oct 2009

  • Migration of the Information System, Perl/MySQL developments
  • Full redesign of the B2C “Alice” customer portal (migration from PHP to Perl)
  • Redesign “Alice” provisioning flows
  • PHP
  • Perl
  • HTML
  • CSS
  • MySQL

Software Engineer @ TIF “Alice”

Jul 2006 – Aug 2008

  • Maintenance, evolution and refactoring of the subscription interface and customer portal in relation with the B2C commercial team
  • Online micro-payment service w-HA
  • SOAP interfaces (IS interconnections)
  • B2C recovery flow management
  • Production delivery management
  • Agile methodology (XP, pair programming)
  • PHP
  • Perl
  • HTML
  • CSS
  • MySQL
  • SOAP


Paris, FR

Software Engineer

Aug 2005 – Jul 2006

  • “IDX::PKI” packaging for publishing
  • 8 month mission for Telecom Italia France, Signup/Selfcare team: B2C customer portal maintenance, SOAP webservices design and development, w-HA payment interface
  • Perl
  • PHP
  • SOAP


IIE-CNAM/ENSIIE engineering diploma (Master’s degree)

Sep 2002 - June 2005

Specialised in advanced information systems and databases, network and security, reasoned programming, robotics and virtual reality.
Guillaume Castagnino
  • +33 6 73 85 46 69
  • 21 rue Roger Henry
    78210 Saint-Cyr-l’École
  • DoB: April 14, 1982


    • Soft skills
    • Analytical
    • Active listening
      Product Management
    • Agile methodology (Scrum, Kanban)
    • Lean
    • Value optimization
    • Jira
    • Strong programming and sysadmin background (Linux)


  • French
  • English
    Professional Working Skills – TOEIC: 875


  • Product Focus Certified Product Manager (2021)
  • PSPO I certified (2018)
  • IIE-CNAM/ENSIIE Engineer (2005)


  • Bike
  • Photography
  • OpenStreetMap
  • System administration
  • Piano