Freelancer profile translated to English.
Back to original languageAbout Joffrey
Flutter & Backend NestJS Developer | Freelance
Software Engineer since 2018, I have specialized since 2020 in Flutter mobile development (+6 years of experience) and NestJS/PostgreSQL backend (over 2 years of experience). I am involved in both architecture and business features, from end to end.
Mobile — Flutter Over 6 years of experience on large-scale projects: SNCF Connect (500,000 users/day), Coffreo, Voisins Vigilants, Taster, Politês. I am involved in architecture (Clean Architecture, BLoC), complex feature development, push notifications, deep links, third-party integrations (analytics, attribution, sharing), and writing tests.
Backend — NestJS / ExpressJS / PostgreSQL (2 years of experience) in designing and developing B2B and B2C REST APIs in a monorepo architecture. My involvement covers business feature development, resource security (IDOR, rate limiting, strict validation), database interactions (migrations, optimized queries), third-party service integration (Stripe, webhooks), CI/CD setup (Bitrise), and test writing (unit, integration, e2e). I apply DDD principles to structure business logic.
📍 Paris — remote or hybrid
French
Native or bilingual
English
Fluent
Can work on-site
Paris (up to 50km), Paris (up to 50km), Cergy (up to 50km)
Experience
- PolitesFlutter & Backend NestJS (PostgreSQL) DeveloperSOCIAL NETWORKSMarch 2025 - April 2026 (1 year and 1 month)Paris, FranceBackend - (NestJS / TypeScript)Comments system: CRUD, replies, reactions, automatic moderation, soft-delete, paginationMulti-device push notifications (registration/unregistration)Version checking & force update system via global guardExternal partner endpoints with Zod validationPolls: anonymous support, skip management, region-adjusted resultsFrontend - (Flutter)Complete mobile app architecture (Clean Architecture, BLoC, DI)Polls system: multi-step creation, swipeable flow, grid with filters, raw/region-adjusted resultsLeaderboards and rankings with period filtersMulti-device push notifications, deep links, and badgesSharing: links, QR codes, result image export, SMSSpecial card system (rating, sharing, notification)Community tab: contacts, invitations, friend profilesUser profile, account management, newsletterComplete onboarding (phone, postal code, tutorial)Analytics integration (Facebook App Events, Branch attribution)
- TasterFlutter Mobile DeveloperRESTAURANTS AND FOOD SERVICEOctober 2024 - February 2025 (4 months)Paris, FranceSoftware enhancements on the Kitchen Assistant application.Retrieval of Uber Eats and Deliveroo rider information, new order sorting in the kitchen, complete redesign of orders.
- SchediumBackend Developer — NestJS / PostgreSQL / ExpressJSSOFTWARE PUBLISHINGNovember 2024 - March 2026 (1 year and 4 months)Paris, FranceDesign and development of 2 REST APIs (B2B & B2C) in a monorepo architecture with shared packages (middlewares, models, utilities)Implementation of multi-layer security: IDOR protection on all resources (12+ ownership middlewares), rate limiting, environment-specific CORS, strict input validation via ZodComplete Stripe integration: creation of Payment Intents, lifecycle management via webhooks (3D Secure, success, failure, refund), automatic cleanup of expired reservationsAES-256-CBC encryption of personal data (PII) with normalization for searching encrypted dataDevelopment of business features: appointment management (booking, cancellation, rescheduling, attendance tracking), employee scheduling, service and service group management, guest system with PII protectionMigration setup (dbmate)Writing test files (unit, integration, e2e) with Vitest and SupertestManagement of local (cash/card) and online payments with transaction tracking and balance calculationStructured middleware pipeline: auth, context extraction, ownership validation, centralized error handling
Reviews
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Education
- Engineering DegreeESIEE PARIS2018- Programmation temps réel C / C++ / Java / UML - Architectures et électroniques embarquées - Principes et concepts de la programmation orientée objet - Logiciels embarqués (régulateur, limiteur de vitesse, kit bluetooth) - Spécification des systèmes à événements discrets - Projet de domotique par commande vocale avec maquette 1/20 - Management des équipes, de projet et leadership - Management de l'innovation, de l'économie et des finances
- Accelerated Certificate ProgramUniversity of California, Irvine Division of Continuing Education2018Certification en management de projet Leadership, gestion des coûts, gestions des risques, management de programme...
Certifications
- TOEIC (Score: 925)TOEIC2017