/ Curriculum Vitae

Thomas Josso

FULL-STACK · TECHNICAL LEAD · WEB & MOBILE

Download Engineering résumé (PDF)

/ 01 · Profile

Profile

Senior full-stack engineer and technical lead. Eight years in, and I've had the good fortune of building across Paris, Shanghai, and New York: at startups raising their first round, at companies shipping to millions, and on side projects of my own. I architect scalable systems with modern technologies, drive process improvements, and implement secure authentication and advanced CI/CD pipelines. My work spans backend and frontend development, AI integration, and leading collaborative, multicultural teams. That range of context is probably my biggest asset.

/ 02 · Experience

Experience

Technical Lead (Founder) · rixAI

Mar 2026 – Present

New York City

  • Implement a strict TypeScript monorepo with Turborepo and pnpm, integrating an Expo mobile app (Expo Router) and a Next.js web app (App Router) that share a tRPC API, Neon PostgreSQL via Drizzle ORM, and Zod v4, enabling consistent code reuse across platforms and reducing development time
  • Use TanStack Query and Zustand in mobile clients, sharing API types from the server through tRPC, which streamlines state management and improves data synchronization performance
  • Design authentication with Supabase, supporting Google, Apple, magic-link flows, and optional Upstash Redis for sessions, caching, and rate limiting, providing a secure and flexible login experience that reduces authentication latency
  • Apply web CSRF protection, sliding-window rate limits, role-based access control, and audit logging in the API layer, strengthening security and compliance for sensitive operations and minimizing unauthorized-access incidents
  • Integrate RevenueCat for native in-app purchases and paywall UI, with server-side access checks and plan-based feature gating, delivering a seamless subscription experience that boosts conversion and retention
  • Implement a debate feature using an XState finite-state machine and Inngest asynchronous workflows to handle step timeouts, AI turns, stale-session cleanup, and post-debate analysis, resulting in smoother debate sessions and fewer interruptions
  • Develop AI chat with the Vercel AI SDK and OpenAI models, adding streaming responses and Langfuse for prompt management and tracing; a layered response system and token limits keep usage within budget, improving response reliability for users
  • Integrate Resend for transactional email, Expo notifications for mobile push, and Vercel Blob storage for user-generated files, which increases delivery reliability and simplifies file handling across platforms
  • Combine Sentry for error and performance monitoring, PostHog for web and mobile analytics, and OpenTelemetry metrics exported to Grafana Cloud, providing real-time visibility that speeds issue detection and improves product decisions
  • Use GitHub Actions for continuous integration and EAS for mobile releases, with Vitest API tests, enabling faster, reliable deployments and reducing release errors

Technical Lead (Founder) · Fitness App

Jul 2023 – Apr 2025

France

  • Developed a viable MVP in the first year and, after missing the target, continued the project as a personal lab to explore new technologies, strengthening full-stack development skills
  • Designed and developed an isomorphic mobile and web app from scratch using React Native and Next.js, delivering a cross-platform experience that improved user engagement
  • Built a GraphQL API with MySQL and implemented multi-platform CI/CD pipelines, reducing deployment time and increasing release reliability
  • Combined market research, user feedback, and input from a fitness coach to design training-focused features, resulting in a feature set that increased user retention

Product Engineer · previously Software Engineer · Amblea

Jan 2020 – Jul 2023

Paris, France

  • Delivered features from technical specification drafting to development, testing, and deployment, ensuring seamless integration and improved user satisfaction
  • Built automated unit, integration, and regression tests in TypeScript, improving release stability
  • Developed with React, Next.js, and React Native to enhance usability and performance, resulting in a more intuitive user experience and faster application load times
  • Resolved incidents and managed migrations with minimal impact on users, maintaining high user satisfaction and system reliability
  • Implemented new features and bug fixes in a React, Next.js, and GraphQL codebase
  • Added Jest and Cypress automated tests, reducing regression issues by 8%
  • Improved the release workflow and developer experience, cutting release time by 40%
  • Promoted React and TypeScript best practices, raising code quality across the team

Frontend Engineer · Boxy

Jul 2019 – Dec 2019

Paris, France

  • Implemented React Native tech stack for scalable and rapid delivery
  • Created a consistent mobile visual identity, supporting €5M fundraising efforts
  • Built a lightweight web app for a retailer demo, leading to partnership discussions
  • Set up continuous deployment for iOS and Android, speeding up delivery cycles

Frontend Engineer · Winamax

Jul 2018 – Jun 2019

Paris, France

  • Built France's first bet combinator, expanding available betting options and enhancing user engagement
  • Updated the interface for the Spanish market launch, improving user experience and accessibility
  • Supervised and mentored three interns during their projects, fostering skill development and ensuring project success

Full Stack Developer · 31Ten

Sep 2016 – Jan 2017

Shanghai, China

  • Built a WeChat app for a luxury brand to reach the Chinese market, enhancing brand visibility and customer engagement
  • Maintained three e-commerce sites and ran targeted ad campaigns for China, increasing site traffic and boosting sales
  • Conducted an in-person project wrap-up with the project manager of a major marketing agency, ensuring final approval and client satisfaction
  • Provided user training to support adoption and usage, leading to increased user proficiency and reduced support requests

/ 03 · Skills

Skills

PROGRAMMING LANGUAGES

TypeScriptJavaScriptSQLHTMLCSS

FRONTEND

ReactNext.jsVercelReact NativeTailwind CSSExpoExpo RouterZustandTanStack QueryServer Side Rendering

BACKEND

tRPCDrizzleNeonSupabaseZodInngestXStateOpenAILangfuseMem0RedisRevenueCatResendNode.jsGraphQLPostgreSQL

TESTING

VitestJestCypress

DEVOPS & TOOLS

VercelSentryPostHogOpenTelemetryGrafanaKnipDockerGitCI/CD

PRACTICES

MonorepoProduct DevelopmentUX/UI DesignSEOCode ReviewProduct ManagementMarket AnalysisBusiness StrategyUser FeedbackCross-cultural DevelopmentEnd-user TrainingEntrepreneurial MindsetRole-Based Access Control (RBAC)CSRFCircuit Breaker

/ 04 · Education

Education & Languages

2013 – 2018

EPITA

Engineering Degree, Computer Science · Grandes Écoles

Paris, France

Languages

French (Native)

English (Fluent)