# Senior Web & Software Developer in France | Sébastien Descloux > Sébastien Descloux, senior freelance developer and CTO based in France. Websites, SaaS and business software for European and international projects since 2013. Web development · SaaS · Software · AI ## Senior full-stack developer for European and international projects I’m Sébastien Descloux, a freelance full-stack developer based in Montlhéry, France. Since 2013, I have worked on websites, SaaS products and business applications. I support European and international teams remotely, with a direct link between business decisions and the technical work. [Discuss your project](https://sdx-development.com/en/contact) 01 **Since 2013** independent web development 02 **Websites & software** web, SaaS and business applications 03 **Remote collaboration** Europe and international projects The person behind SDX Development ## One developer, from your idea to a working product You work directly with the person who designs, develops and maintains your website or application. My role is to understand your business and turn that understanding into a useful tool: a clearer website, a smoother enquiry process, a shared view of your data or less repetitive work for your team. Remote projects need clear communication. We agree on priorities, review working versions and record decisions as the project moves forward. This gives you a practical way to follow progress, whether your team is in Europe or further afield. I also serve as CTO at Groupe WE, where I develop digital products for field operations. That experience informs my work on websites, business software, SaaS applications and AI systems connected to real workflows. Find my professional background on [LinkedIn](https://www.linkedin.com/in/s%C3%A9bastien-descloux-9a1b67431/) and my articles on [DEV Community](https://dev.to/sdx_development). - **Independent since 2013**Web development and custom software. - **CTO · Groupe WE**Architecture, business applications and digital platforms. - **Web, SaaS & AI**Interfaces, software, data, automation and deployment. Professional networks ## Find SDX Development on IONOS and France Num These public profiles describe my web and software development work. You can visit each platform to read the information it publishes about SDX Development. [![Logo IONOS](https://sdx-development.com/assets/site/images/professional-networks/ionos.svg)](https://partnernetwork.ionos.fr/partner/sdx.development) ### IONOS Partner Network SDX Development’s profile on the IONOS partner network. [View the IONOS profile ↗](https://partnernetwork.ionos.fr/partner/sdx.development) [![Logo France Num](https://sdx-development.com/assets/site/images/professional-networks/france-num.svg)](https://www.francenum.gouv.fr/activateurs/sdx-development) ### France Num Activator SDX Development’s listing in the France Num Activators directory. [View the France Num profile ↗](https://www.francenum.gouv.fr/activateurs/sdx-development) Based in France, working across borders ## Web development for businesses in Europe and beyond A successful remote project starts with a shared understanding of the work. Before development begins, we define the main use cases, the scope, the budget and the delivery stages. We also agree on meeting times that work across our time zones, so you know when we can review progress together. During the project, demonstrations and written feedback help turn requirements into concrete decisions. You can see what has been built, test the important workflows and raise questions before the next stage. If the product serves several countries, we can plan for languages, currencies, content and integrations during scoping, according to your actual needs. The starting point may be a [new website](https://sdx-development.com/en/custom-web-development), a [website redesign](https://sdx-development.com/en/website-redesign), [custom business software](https://sdx-development.com/en/custom-business-software) or a [SaaS product or MVP](https://sdx-development.com/en/saas-mvp-development). In each case, the aim is a manageable first release and a clear plan for what follows. Tell me where your team is based, what you need to achieve and the constraints we should account for. ## Selected projects and experience Business software ![Intervention calendar: teams, time slots and access to job details from the schedule.](https://sdx-development.com/media/idea-to-software/agenda.webp) ### Idea to Software A business ERP connecting job management, constraint-based scheduling, inventory, invoicing and a customer portal, with ITS Report for video inspection. - [Explore the case study →](https://sdx-development.com/en/case-studies/idea-to-software) - [Explore the platform ↗](https://www.idea-to-software.com/) Inspection software ![Embedded ITS Report: video, capture controls, annotations and playback.](https://sdx-development.com/media/idea-to-software/embarque-interface.webp) ### ITS Report on inspection equipment ITS Report on inspection equipment: local video, captures and reports, with guided navigation and an interface built for field operators. - [Explore the case study →](https://sdx-development.com/en/case-studies/idea-to-software#its-report-embarque) - [Explore ITS Report on inspection equipment ↗](https://www.idea-to-software.com/valise-inspection-avec-interface-its-report-rapports-en13508-2) - [Release history ↗](https://www.idea-to-software.com/its-report-on-prems/historique-des-versions-serveur-valise-its-report-on-prems-telechargements) Operational monitoring ![A fleet-wide map brings current states and equipment requiring attention into one view.](https://sdx-development.com/media/ratp-dashboard/connected-toilette-cabine-dashboard-map-main.webp) Internal business application ### RATP Toilettes Connectées An IoT monitoring platform connecting equipment data, operational incident reports, device commands and resolution tracking. From field data to investigation and resolution tracking, the platform connects the operational workflow. [Explore the project →](https://sdx-development.com/en/case-studies/operational-dashboards) Digital ecosystem ![Résiliner homepage: visual identity, navigation and access to diagnostic enquiries.](https://sdx-development.com/media/resiliner/home.webp) ### Groupe WE, Résiliner & WE Robotics Websites for several group companies, connecting their field operations, industrial services and digital tools through clear user journeys. Résiliner also has an administration interface for pages, media, menus and publishing, with dedicated journeys for its method and network development. - [Explore the case study : Résiliner →](https://sdx-development.com/en/case-studies/resiliner) - [Groupe WE ↗](https://www.groupe-we.com/) - [Résiliner ↗](https://resiliner.groupe-we.com/) - [WE Robotics ↗](https://we-robotics.groupe-we.com/) Service businesses ![Génération Location homepage: brand identity and search by branch, category and dates.](https://sdx-development.com/media/generation-location/home.webp) ### Websites for service businesses Websites that explain a company’s services, make its expertise easy to understand and help prospective customers get in touch. Génération Location connects its commercial website with a manageable catalogue and a dedicated module for adding rental vehicles. - [Explore the case study : Génération Location →](https://sdx-development.com/en/case-studies/generation-location) - [Génération Location ↗](https://www.generation-location.fr/) - [Hydro Cars ↗](https://www.hydro-cars.fr/) - [Bien Vivre au Portugal ↗](https://www.bienvivreauportugal.com/) My approach ### Continuity from planning to production I treat each project as a product that will keep evolving. Interface design, architecture, data and deployment are considered together throughout the work. 1. **Define**Goals, use cases and practical constraints. 2. **Build**Interfaces, business logic and maintainable architecture. 3. **Connect**APIs, data, AI and field equipment. 4. **Improve**Measurement, maintenance and ongoing development. One technical point of contact, from initial scoping through launch and subsequent improvements. - [Discuss your project →](https://sdx-development.com/en/contact) ![Current Amophys website](https://sdx-development.com/media/reference-amophys.webp)![Current Lisbonne Immobilier website](https://sdx-development.com/media/reference-lisbonne-immobilier.webp)![Current Assurances Food-Truck website](https://sdx-development.com/media/reference-assurances-food-truck.webp) Development contributions ### Amophys, Lisbonne Immobilier & Assurances Food-Truck I contributed to earlier versions of these websites. The versions online today have since been updated without my involvement; these references describe my contribution at the time, rather than responsibility for their current implementation. - [Amophys ↗](https://www.amophys.fr/) - [Lisbonne Immobilier ↗](https://www.lisbonne-immobilier.com/) - [Assurances Food-Truck ↗](https://www.assurances-food-truck.fr/) Technology chosen to fit the project ## From the first design to a dependable release PHP, JavaScript, jQuery, Python and Node.js are among the technologies I use most often. The choice depends on your requirements, existing systems, security constraints and the expected lifespan of the product. The goal is a solution your team can use and maintain: saving time, making a process more reliable, clarifying data or making a service easier to access. **Build a solid foundation**PHP for business applications, APIs, content management systems and database-backed services. **Make interfaces easier to use**JavaScript and jQuery for responsive interfaces that are clear and straightforward to manage. **Automate and analyse**Python and Node.js for data processing, AI, automation and web services. **Integrate AI into real workflows**RAG, copilots, computer vision and agents connected to existing business data and tools. Support after launch ## Technical audits, incident response and ongoing maintenance Websites and applications need attention over time. Dependencies change, access permissions accumulate and business needs evolve. I review existing systems, investigate incidents and plan improvements to help keep your tools reliable. **Has your website been defaced, started redirecting visitors or displayed suspicious content?** I begin by investigating the entry point, code and access records, then remove malicious components, restore the site in a controlled way and address the weaknesses identified. Prevention ### Cybersecurity audits A technical review of exposed services, accounts, permissions, updates, backups and weaknesses. Recommendations are prioritised by risk and business impact. Incident response ### Website and application recovery Investigation of malicious code, backdoors and exploited vulnerabilities, followed by remediation and recommendations to reduce the risk of another incident. Ongoing support ### Maintenance and improvements Targeted fixes, updates, monitoring and further development to keep your software useful, maintainable and aligned with changing needs. ## Related case studies ![Intervention calendar: teams, time slots and access to job details from the schedule.](https://sdx-development.com/media/idea-to-software/agenda.webp)Business software ### Idea to Software A business ERP connecting job management, constraint-based scheduling, inventory, invoicing and a customer portal, with ITS Report for video inspection. [Read the case study →](https://sdx-development.com/en/case-studies/idea-to-software) ![Résiliner homepage: visual identity, navigation and access to diagnostic enquiries.](https://sdx-development.com/media/resiliner/home.webp)Website ### Résiliner An industrial website with a custom CMS: technical content, the C.A.R.E. method, project references, franchise information and diagnostic enquiries. [Read the case study →](https://sdx-development.com/en/case-studies/resiliner) ![A fleet-wide map brings current states and equipment requiring attention into one view.](https://sdx-development.com/media/ratp-dashboard/connected-toilette-cabine-dashboard-map-main.webp)Supervision ### RATP Toilettes Connectées An IoT monitoring platform connecting equipment data, operational incident reports, device commands and resolution tracking. [Read the case study →](https://sdx-development.com/en/case-studies/operational-dashboards) ## A project you would like to move forward? Tell me about the goal, the context and the constraints. We can define a useful first scope. [Discuss your project](https://sdx-development.com/en/contact)[View pricing](https://sdx-development.com/en/pricing) --- [View the HTML page](https://sdx-development.com/en/about)