Hi, I'm

Sylvain Leroy

Cloud Solution Architect & Software Modernization Strategist

AWS Specialist Solution Architect with 20+ years of experience leading legacy-to-cloud transitions at scale. I help businesses evolve through technology, bridging business vision with sustainable technical execution across startups, scaleups, and large enterprises in banking, insurance, SaaS, and telecom.

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About Me

Cloud Solution Architect and software modernization strategist with 20+ years of experience leading legacy-to-cloud transitions and helping businesses evolve through technology.

At AWS, I specialize in complex migrations and application modernization at scale (AWS/GCP certified). My background spans startups, scaleups, and large enterprises in industries like banking, insurance, SaaS, and telecom—always bridging business vision with sustainable technical execution.

Beyond hands-on architecture, I collaborate directly with business leaders and C-levels to shape roadmaps, structure teams, and ensure technology directly supports growth and innovation.

I founded Byoskill, a boutique consulting practice, and co-lead OnlyWine.ch, blending wine culture, digital innovation, and storytelling. Currently based in Switzerland, I’m open to strategic CTO, IT Management, or advisory roles where I can bring together vision, leadership, and technical excellence to scale impactful software businesses.

What I bring to your organization:

Cloud Architecture, Migration & Cost Optimization (AWS/GCP)
Legacy Modernization & Automated Refactoring (Java, Node.js, PHP, C++, Python)
SaaS Platform Development & Secure Systems Design
Disaster Recovery, High Availability (PostgreSQL, Patroni)
Fractional CTO Support for Software Editors & Entrepreneurs
C-Level Collaboration & Technology Roadmap Planning
Team Structuring & Technical Leadership
Microservices Architecture & Enterprise Integration
DevOps, CI/CD & Infrastructure as Code
Strategic Technology Advisory & Business Alignment

Experience

Specialist Solution Architect - Migration and Application Modernisation - Amazon Web Services (AWS)

Jan 2023 - Present

As a Software Architect at AWS, I bring the best of Cloud innovation to customers and accompany them in their journey. My responsibilities include:

Building customer business cases for cloud migration
Cost optimization strategies and implementation
POC development and architecture design workshops
Daily support for migration and modernization projects
Solution architecture for enterprise cloud transformations

Founder / Freelance Consultant - Byoskill

May 2018 - Present

Founded IT consulting company specializing in Software Craftsmanship, training, and legacy software migration:

Startup technical acceleration and MVP development
Legacy software migration with automated processes
Java/JavaScript expertise for rapid prototyping
Software Quality Assurance consulting
Training on Gradle, Groovy, JUnit 5, and Quarkus

Team Leader - LzLabs

Sep 2021 - Dec 2022

Led development team responsible for three products improving mainframe-to-cloud development experience:

Mainframe development platform (Cobol, CICS, PL1, ASM, C/C++)
Automated testing tools for mainframe applications
Code analysis platform for mainframe software assessment
Team management of 3+ developers using Spring, React, and mainframe technologies

IT Consultant / Freelancer - Various Strategic Roles - IT Consulting & Freelance

2017 - 2020

Combining multiple strategic technology leadership roles across Swiss organizations:

Fractional CTO for software companies and startups
Director of Software Development for Private Banking institutions
Solution Architect for enterprise cloud transformations
Strategic technology advisory for digital transformation projects
Team leadership and technical mentoring across diverse industries

CTO | Director of Technology - Metrixware

2015 - 2016

Technical leadership for RAPID product line specialized in automatic legacy system migration:

Strategic direction for legacy modernization projects
Framework development for safer, faster code migration
Technical advisory for enterprise modernization initiatives

Co-Founder & CTO - Tocea

Jan 2011 - Dec 2015

Co-founded and led technology development at Tocea, focusing on software quality assurance tools and legacy system modernization solutions.

Projects

Swiss Salary Calculator

A comprehensive salary calculator for Switzerland with tax calculations, social security contributions, and net salary computation.

Try it

Swagger to PlantUML Converter

A developer tool that converts Swagger/OpenAPI specifications into PlantUML diagrams for better API documentation and visualization.

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Byoskill - Boutique IT Consulting

Founded boutique consulting practice specializing in Software Craftsmanship, legacy migration, and startup technical acceleration. Providing fractional CTO services and enterprise modernization expertise.

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OnlyWine.ch - Digital Innovation & Storytelling

Co-leading a Swiss wine culture initiative that blends digital innovation with storytelling, featuring web content creation, online shop development, and digital marketing strategies.

Explore Project

Technical Articles & Blog

Regular technical articles covering application modernization, cloud technologies, Java development, and DevOps best practices.

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Achievements

Cloud Architecture Expertise

Designed and implemented numerous cloud migration projects helping organizations modernize their infrastructure.

Open Source Contributions

Active contributor to various open-source projects related to Java development and DevOps tools.

Technical Writing

Published extensive technical articles on application modernization, cloud technologies, and software architecture.

Enterprise Consulting

Successfully guided multiple enterprises through their digital transformation journey.

Get in Touch

Open to strategic CTO, IT Management, or advisory roles where I can bring together vision, leadership, and technical excellence to scale impactful software businesses. Let’s discuss how I can help transform your technology roadmap into sustainable growth.

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