Freelancer profile translated to English.
Back to original languageAbout Guillaume
🚀 Expert Backend & SRE | High Performance
"Code is worthless if it doesn't scale."
Co-founder of the agency Miinded (**€4.5M revenue**), I have been working on critical systems for 15 years. My expertise: ensuring your platform remains performant, even during massive peaks (reference: 130k simultaneous connections).
I help companies stabilize their technical growth and modernize their complex applications.
🔧 TECHNICAL EXPERTISE
My hybrid Dev & Ops profile covers your entire technical chain:
Backend: Distributed systems (Node.js/NestJS, .NET, PHP/Symfony), cache (Redis), and message queues (RabbitMQ).
Infra & SRE: Kubernetes, Docker, CI/CD pipelines (GitLab, Azure DevOps), and Cloudflare protection.
Modernization: Technical debt audit and heavy refactoring without service interruption (Monolith to Cloud-native).
🎯 RESULTS & BUSINESS APPROACH
I understand your challenges and the need for measurable results:
- **Reliability**: Monitoring and processes (Rollback, Feature Flags) to eliminate deployment stress.
- **Efficiency**: Code/DB optimization to reduce server load and infrastructure costs.
- **Crisis Management**: Intervention on system locks (OS, DB tuning) to unblock saturated platforms.
📈 KEY FIGURES
- 40+platforms delivered: From multi-tenant SaaS to electronic signatures.
- €13Mgenerated for my clients through the platforms designed.
- 15 yearsof experience: From development to real-world operations.
📍 PRACTICAL INFORMATION
Location: Mougins (06) and its surroundings, Full Remote or Hybrid.
Stack: .Net, NestJS, Kubernetes, PostgreSQL, Redis, RabbitMQ.
Languages: French (Native), English (B2).
Is your backend slowing down or needs to scale? Let's discuss it.
French
Native or bilingual
English
Fluent
Can work on-site
Mougins (up to 50km)
Experience
- MiindedCo-founder / Backend & DevOps EngineerTECHOctober 2021 - Today (4 years and 10 months)Peymeinade, FranceCo-founding and technical leadership of an agency specializing in critical platforms (Web3, SaaS, Gaming). Responsible for the architecture and reliability of infrastructures for 40+ delivered projects.🚀 TECHNICAL CHALLENGES & RESCUES:
- **Smart Contract Audit & Security**: Development and deployment of contracts where errors are fatal. Ultra-strict unit and functional tests (maximum coverage) to prevent logical and reentrancy flaws, securing millions of euros in assets.
- **Crisis Exit (Unity/Web3)**: Taking over a multiplayer game blocked by massive technical debt. Gaining proficiency in Unity/C# in 3 weeks to stabilize the code, optimize performance, and deliver while regaining cost control.
- **High Availability**: Kubernetes orchestration (Scaleway/OVH) with auto-scaling (HPA) to handle critical launches with 130k simultaneous connections.
- **Infrastructure & CI/CD**: Industrializing deployments (Dev/Prod ISO) with a Time-to-Deploy < 6 min. Resource optimization through targeted builds by file patterns.
- **Scraping & Blockchain Feeds**: Data collection via WebSockets / RPC with Rate Limiting management, API fallback to ensure data integrity under heavy load.
- **Quality**: OpenAPI/Swagger documentation and systematic cross code reviews to eliminate any single point of failure.
💼 BUSINESS IMPACT:- **Cost Control**: Internalizing critical developments to eliminate reliance on external providers.
- **Strategic Consulting**: Assisting clients with their architectural choices by outlining technical limitations (scalability, cloud costs) and alternative solutions.
- **Result**: Over €13M in secured business volume.
- Radioactiv'itExpert Fullstack & DevOpsPUBLIC SECTORJanuary 2018 - January 2022 (4 years)Sophia Antipolis, FranceSenior consultant involved in critical missions for application stabilization and modernization.🚀 MAJOR MISSION: RESCUE AND INDUSTRIALIZATION (Dematerialization Sector)Intervention for a leader in electronic document signing (signature workflow management) following a loss of control over the build cycle.
- **Software Factory Reconstruction**: Taking over a complex platform where only one local machine could still compile. Critical migration from TFS to Git, restructuring the multi-repo architecture, and setting up an automated build platform (CI/CD) under GitLab and then Azure DevOps.
- **Stabilization & Quality**: Audit and correction of massive technical debt on electronic signature workflows. Resolution of critical functional errors and streamlining of business processes.
- **Technological & Strategic Evolution**: Transitioning the frontend to Vue.js to modularize the application. Then, a technological pivot to Blazor upon acquisition by a consortium, to pool .NET team skills and accelerate integration without a JS learning curve.
🚀 SECONDARY MISSION: HDS MEDIA PLATFORMDesign of a video content management platform (like "OnlyFans") with high security constraints in Nuxtjs.- Integration ofsubscriptionsvia Stripe.
- **HDS Architecture**: Setting up a health data/sensitive data hosting environment.
- **Video Processing**: Managing large-scale video generation and storage streams.
💼 BUSINESS IMPACT:- **Audit & Recovery**: Transforming "hostage code" in an unstable environment into a scalable and documented industrial asset.
- **HR Optimization**: Technological choices (Blazor) aligned with the acquirer's resources to reduce training and maintenance costs.
- **Result**: Complete upgrade of software quality and securing the company's technical value.
- La Boite ImmoBackend Developer & Automation (SaaS)REAL ESTATEJanuary 2017 - January 2018 (1 year)Hyères, FranceInvolved in a multi-tenant real estate ERP (200+ clients) managing massive volumes of data exports (real estate portal feeds).🚀 TECHNICAL CHALLENGES & "CUSTOM" SOLUTIONS:
- **Critical PHP 4 to 5 Migration**: Design and use of a custom code migration tool to automate syntactic replacements and deprecated functions. Incident recovery management to ensure code integrity across the entire application base during the switch.
- Debugging & Contextualization Tooling: Creation of a system to dynamically extract a client instance's backend and couple it with a local database. This solution allowed reproducing bugs in the actual context on development machines, ensuring surgical resolution of production incidents.
- **SQL Synchronization Engine (Open Source)**: Creation of a schema comparison tool based on the raw definition of MySQL tables. This solution allowed identifying structural differences between the 200+ client instances and generating adapted migration scripts without third-party frameworks.
💼 BUSINESS IMPACT:- **Technical Efficiency**: Reduced critical incident resolution time thanks to diagnostic tools created for the technical team.
- **Code Security**: The PHP 5 migration, managed by a failure-handling tool, saved the software from technical obsolescence without service interruption.
- **Data Reliability**: Standardization of a complex database park using the SQL "diff" logic published as Open Source.
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Education
- DUT in Communications Networks and ServicesIUT Saint-Raphaël2011DUT Service et Réseaux De Communications
- Professional Bachelor's Degree in Computer Systems and SoftwareIUT2012Licence Professionnelle Systèmes Informatiques et Logiciels
Certifications
- AWS Cloud Quest: Serverless Developer - Training BadgeAWS2026