Freelancer profile translated to English.
Back to original languageAbout Bertrand
Are you looking for a Ruby on Rails developer to build or evolve your SaaS product?
You've come to the right place 👇
I help startups and companies with the design, evolution, and scalability of their web applications, with strong expertise in Ruby on Rails backend and SaaS architecture.
With over 6 years of experience, I work on projects ranging from MVPs to production platforms with significant performance and robustness challenges.
I have worked for about fifteen clients, including companies like Qonto (FinTech), Leto (GDPR), Holivia (Health), Maltem Canada (ESN), as well as several other startups and web agencies.
I have managed projects solo and others in agile teams.
I quickly adapted to existing projects.
🧠 What I do concretely
I help my clients to:
- design and develop robust SaaS applications in Ruby on Rails
- build performant and scalable APIs
- improve the performance, scalability, and maintainability of existing applications
- modernize codebases (upgrade Ruby / Rails / gems, refactoring, migration)
- integrate automation and AI features into web products
- set up reliable deployment and testing workflows (CI/CD)
⚙️ Types of missions
- creation of SaaS MVPs from scratch
- redesign or improvement of existing applications
- backend API development
- performance and scalability optimization
- technical audit and refactoring
- integration of AI features on the backend
🤝 My way of working
I favor clear and transparent collaboration:
- weekly check-ins with my clients
- direct and efficient communication
- maintainable code designed for teams
- quick integration into existing projects
🎯 Objective
Deliver reliable, scalable products capable of supporting your business growth.
👉 Available to discuss your project.
French
Native or bilingual
English
Fluent
Can work on-site
Marseille (up to 50km), Lyon (up to 50km), Paris (up to 50km), Bordeaux (up to 50km), Montpellier (up to 50km)
Experience
- QONTO - TECHRuby on Rails DeveloperBANKING AND INSURANCEApril 2025 - April 2026 (1 year)Marseille, FranceRefactoring of the website: Qonto Community is a discussion forum dedicated to financial directors (CFOs).Missions🎯✔ Integration of the new design✔ Refactoring of the onboarding flow✔ Significant optimization of SEO✔ Optimization of marketing data✔ Automation of CI/CD with workflows✔ Reduction of infrastructure costs✔ Management of server load and occasional peak loads✔ Streamlined user experience with background jobs✔ Improvement of automatic test coverage to 87%✔ Setup of monitoring via Sentry + Slack✔ Fix of all bugs reported in Sentry✔ Update of the technical stack to more recent versions (Ruby, Rails, Solid Queue, gems)✔ Improvements via Claude Code agents: security, performance, scalability✔ Analysis of LLM User-Agents in logs✔ International team✔ Multilingual website + translation managementTech Stack💻Backend:Ruby on Rails, PostgreSQL, Solid QueueFrontend:TailwindCSS, HotwireTests and Linter:RSpec, RubocopInfra:Heroku, S3, CI/CD workflowsLog analysis:Papertrail, LogrageAI:Claude Code, CursorSEO🚀✔ Sitemap (auto-updated daily)✔ Enriched Content (Rich Snippets)✔ Custom URLs✔ Redirects✔ Meta Tags✔ Breadcrumbs✔ Canonical URLs✔ Duplicate Content Management✔ Custom Error Pages✔ Cache✔ Compression✔ Lazy image loading✔ Web-optimized images (SVG)✔ Page load speed (N+1 query)✔ HTTPS - SSL✔ robots.txt✔ llms.txt
- LetoRuby on Rails DeveloperCONSULTING AND AUDITSMarch 2024 - October 2024 (8 months)Paris, FranceLeto is a startup that supports DPOs and facilitates GDPR compliance for their companies (SMEs and subcontractors).Creation and updates of legal documents, team awareness, dedicated web page to display their compliance.Working in a team of 6 people consisting of:2 fullstack developers, 1 CTO, 1 CPO, 1 CSM / PO and 1 Growth.Missions🎯✔ Understand different client contexts✔ Improve prompts for API calls to OpenAI✔ Integration of SSO (Single Sign-On) via JWT using Cryptr API✔ Redesign of the email awareness module✔ Optimization of SQL queries (response time reduced by 80%)✔ Split into several asynchronous unit jobs for Microsoft Teams synchronization✔ Improvement of existing systems (Back, Front, Architecture)✔ Writing of automatic tests (unit, integration)✔ Writing of documentation (technical and process)✔ Communicate with and challenge the Product team✔ Pair programming✔ Quoting and scoping of ticketsTech Stack💻Backend:Ruby on Rails, PostgreSQL, Sidekiq, OpenAI, CryptrFrontend:Bootstrap, HotwireTests and Linter:Minitest, RubocopInfra:CleverCloud, GitHub workflows, Sentry
- Ambition CitéRuby on Rails DeveloperEDUCATION AND E-LEARNINGApril 2023 - March 2025 (1 year and 10 months)Marseille, FranceWeb and mobile application designed to help teachers take notes on their students.The goal is to improve their positive teaching approach to adapt to students' needs (Montessori type).Missions🎯✔ Complete CSS redesign of the MVP to match the mockups created on FIGMA by the UX/UI Designer✔ Enable sharing of student observations between multiple teachers✔ Enable easy transfer of class or individual student administration to another teacher✔ Enable easy execution of mass actions with multi-select (delete observations, transfer students, ...)✔ A user can easily delete their account✔ Create a dashboard for administrators with the requested KPIs✔ Management of in-app notifications with new features✔ Asynchronous processing of time-consuming actions for a better user experience and reduced loading time✔ Implementation of automatic tests to ensure every URL on the site is accessible✔ Harmonization of code syntax✔ Encryption of certain sensitive data✔ Data import via CSV files✔ Redesign of tag managementTech Stack💻Backend:Ruby on Rails, PostgreSQL, Sidekiq, APIFrontend:Bootstrap, HotwireTests and Linter:Minitest, RubocopInfra:Scalingo, GitHub, PWA, Sentry
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Education
- Prompt Engineering & AIlearnprompting.org2024✔ Prompt Engineering ✔ LLM
- Online MOOCOpenClassrooms.com➡️ SEO ➡️ DevOps ➡️ UX/UI design ➡️ Green IT ➡️ SCRUM ➡️ Web Accessibility
Certifications
- Web Application Designer / Developer (Bac+3/4 level)Le Wagon - Marseille2020