Android DeveloperAgentic CodingWeb + Mobile

Xavier Maximin · Lyon, France · Available now, permanent or freelance

Background

I have been building software since 2010. I started with five years of Java/JEE at Capgemini, CGI and Sopra Steria, on enterprise applications for EDF, E.Leclerc, MAIF and ASP. In 2016 I moved to Android with a music player app for Squirrel.fr, and taught Android courses for Cegos and Société Générale.

In 2017 I moved to London. At Google I supported the European rollout of Android Pay. Then, for two years at BBOXX, I became the sole Android developer of the app used by agents selling solar kits in Africa: a full rewrite in Kotlin, offline-first for low-connectivity areas, around fifty production releases, and a field trip to Kigali. In 2019 I also did a short assignment in Geneva for the University Hospitals.Case study: BBOXX

I was then the sole Android developer at two UK companies: Skiddle, an event ticketing app based in Manchester, working fully remote from London during COVID (Stripe and Google Pay payments, magic-link sign-in), then Lofti, in property management, in central London (maintenance module, real-time messaging, first release on the Play Store).Case study: Skiddle

In late 2022, from Guadeloupe, I joined the discovery+ team at Warner Bros. Discovery as a freelancer, working on the video player during live sport. After a relocation period in Guadeloupe, I came back to mainland France in 2025: Android lead at Free, an encrypted-messaging prototype at HENSOLDT, then nine months at Bedrock Streaming in Lyon, in the Player & Ads team of the platform behind M6+, RTL+ and Videoland.Case study: discovery+ · HENSOLDT · Bedrock

Since summer 2026 I have been working with agentic coding, using agents such as Claude Code, on web and mobile alike. As the sole developer, I carried Auchan Côte d’Ivoire’s website from end to end: starting the project on the business side, gathering requirements, producing mockups and the first Figma draft, validating and testing with the client, then three months of Ruby on Rails development up to the production launch on 1 October 2026. The freelance assignment is ongoing: I built an interactive mockup of a mini-ATS for the HR team. References on request: Odette Ngamamba (Head of Marketing, auchan.ci) or Sala Traoré (System Administrator, Auchan Côte d’Ivoire). I am building Halostream on the side.Case study: Auchan Côte d’Ivoire

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Right now

Side project in progress

Halostream

A white-label video streaming platform for creators: VOD catalogue, subscriptions and payments, built-in ad server, creator studio and advertiser marketplace. I have been building it on my own since October 2026, with agentic coding. It is an exploration project: the feature scope and the business model are still evolving as I pivot.

Backend: Java 21, Spring Boot 4, Spring Modulith modular monolith
AdTech: VAST / VMAP: ad-break schedule served with playback, VAST decisions, impression tracking
Layout: server-driven: the backend describes each screen’s theme and rails, clients render it without a new release
Video: ffmpeg transcoding to HLS, hls.js playback
Data: PostgreSQL 17, Flyway, S3 storage (Garage), Stripe payments
Web: Next.js 16, React 19, Tailwind CSS 4
Infra: Terraform, Docker Compose deployed on Coolify
Next: describe screens with server-side Jetpack Compose and render them in Kotlin Multiplatform clients, keeping only OS-bound parts such as the video player native

Visit halostream.xaviermaximin.com ↗

Apps

auchan.ci

Auchan Côte d’Ivoire · since Jul 2026 · ongoing · Case study · auchan.ci ↗

Started and run on my own: business, features and engineering, through to the 1 October 2026 launch. Ongoing assignment, including a mini-ATS mockup for the HR team. References on request: Odette Ngamamba (Head of Marketing, auchan.ci) or Sala Traoré (System Administrator, Auchan Côte d’Ivoire).