Portrait of Renaud Mathieu

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Renaud Mathieu

Android • iOS • Kotlin Multiplatform

Freelance mobile lead — I help teams ship polished apps faster. 10+ years, 30+ conference talks, co-founder of Doppio Lab.

Paris, France · remote-friendly

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Spoken at droidcon (SF · Berlin · London · Lisbon) · Android Makers · Devoxx — 30+ talks

Blog posts

AI

Android's Agent-First Era
AIJuin 2026

Android's Agent-First Era

Build-Time vs Runtime

The word "agent" now means two different things in Android development, and they are easy to mix up. This article untangles build-time agents from runtime agents, and what each means for how we ship Android apps. Published in ProAndroidDev.

Date

Dealing with Date objects in Android
DateJuin 2023

Dealing with Date objects in Android

Part 1 - What day is it today?

This series of articles explores how dealing with date objects is not as straightforward as it may initially seem. The complexity arises from various factors, such as different calendars, time zones, and the irregular rotation of the Earth.

Dealing with Date objects in Android
DateJuin 2023

Dealing with Date objects in Android

Part 2 — History of Date in Java

This series of articles explores how dealing with date objects is not as straightforward as it may initially seem. The complexity arises from various factors, such as different calendars, time zones, and the irregular rotation of the Earth.

Ktor

Deploy a microservice in Kotlin with Ktor
KtorJuillet 2021

Deploy a microservice in Kotlin with Ktor

Part 1 - Get started

This series of articles explores the process of deploying a microservice in Kotlin using Ktor, a powerful framework for building asynchronous server-side applications. With its lightweight nature and intuitive syntax, Ktor offers an efficient solution for developing and deploying microservices. We dive into the step-by-step process of setting up a microservice, configuring Ktor for optimal performance, handling HTTP requests, and deploying the microservice to a production environment.

Deploy a microservice in Kotlin with Ktor
KtorJuillet 2021

Deploy a microservice in Kotlin with Ktor

Part 2 - Design the foundation of our API

In the first part of this series about deploying a microservice in Kotlin, we set up a Ktor project. We have seen setting up such a project is quite straightforward, this second part is about how to design robust API specifications that your server and clients can adhere to.

Deploy a microservice in Kotlin with Ktor
KtorJuillet 2021

Deploy a microservice in Kotlin with Ktor

Part 3 - Access our database with Jetbrains Exposed

Jetbrains provides an ORM framework for Kotlin called Exposed. Since we are fully committed to Kotlin and building a Ktor microservice, we didn’t really challenge using Exposed when we started. Nonetheless, despite its verbosity, Exposed has Coroutines support and, as expected, lives up to our expectations.

Material 3

Discovering Material 3 Expressive
Material 3Juillet 2025

Discovering Material 3 Expressive

FAB Menu

At Google I/O 2025, Google unveiled Material 3 Expressive, the latest evolution of its design system. This article explores the new FAB Menu component and how to use it in your Android apps.

Discovering Material 3 for Android
Material 3Août 2024

Discovering Material 3 for Android

Part 4 - SwipeToDismissBox

This series of articles is designed to help you explore the latest addition to Material 3 for Android. In this series, we will take a closer look at the different components and features of Material 3, and explore how they can be used to create modern and user-friendly Android apps.

Discovering Material 3 for Android
Material 3Mai 2023

Discovering Material 3 for Android

Part 1 - ListItem

This series of articles is designed to help you explore the latest addition to Material 3 for Android. In this series, we will take a closer look at the different components and features of Material 3, and explore how they can be used to create modern and user-friendly Android apps.

Discovering Material 3 for Android
Material 3Mai 2023

Discovering Material 3 for Android

Part 2 - DatePicker

This series of articles is designed to help you explore the latest addition to Material 3 for Android. In this series, we will take a closer look at the different components and features of Material 3, and explore how they can be used to create modern and user-friendly Android apps.

Discovering Material 3 for Android
Material 3Mai 2023

Discovering Material 3 for Android

Part 3 - SearchBar

This series of articles is designed to help you explore the latest addition to Material 3 for Android. In this series, we will take a closer look at the different components and features of Material 3, and explore how they can be used to create modern and user-friendly Android apps.

Tooling

Set up a new Mac in 10 minutes
ToolingMai 2026

Set up a new Mac in 10 minutes

My portable dev setup

A macOS setup (tested on Tahoe) for developers who switch machines often: a portable, scripted dev environment that gets a fresh Mac ready to work in about ten minutes.

Services

Hands-on builder, trusted tech leader, and pragmatic auditor.

Android & Kotlin as the foundation.

Start faster

Ship polished mobile apps, faster

Hands‑on engineering, pragmatic leadership, and audits that unlock momentum.

Tell me about your project
Store‑ready
Native & KMP
CI/CD
Observability
Build & ShipCompose • KMP

Build & Ship (Hands‑on)

Heavily focused on the user experience, with a touch of Kotlin Multiplatform.

Tech Leadership

Tech Leadership

Interim/part‑time Mobile Lead/Staff Engineer. Team coaching, review culture, delivery rituals.
Architecture choices and continuous improvement.

Technical Due Diligence & Audits

Technical Due Diligence & Audits

Codebase health, risks & roadmap. Store readiness, privacy, push/notifications. Migration plans that de‑risk and accelerate.

Android • iOS

Offline‑first, performance, polish.

Automation

CI/CD hygiene, testing strategy.

Connect with me

Ventures

Beyond solo work — the agency I co-founded and what we're building.

Agency

Doppio Lab

Co-founder of Doppio Lab, a Paris-based agency crafting premium mobile experiences — iOS, Android, and the backends that power them.

Work with us
Private beta

Local Legends

Your trip. Your vibe.

We're building a privacy-first travel planner that crafts day-by-day itineraries matched to your style and pace.

locallegends.fr ↗

Conferences

Offline-first should be the norm — Android Makers by droidcon
Apr 09, 2026Android Makers by droidcon

Offline-first should be the norm

Android Makers

Replay
Common pitfalls in engineering teams and how to avoid them — droidcon London
Oct 30, 2025droidcon London

Common pitfalls in engineering teams and how to avoid them

Droidcon London

ReplaySlides
Strumming up a music player with CMP 🤘 — droidcon Berlin
Sep 04, 2025droidcon Berlin

Strumming up a music player with CMP 🤘

Droidcon Berlin

ReplaySlides
Jouons de la musique avec Compose Multiplatform — DevLille
Jun 12, 2025DevLille

Jouons de la musique avec Compose Multiplatform

DevLille

ReplaySlides
Les pièges courants dans les équipes techniques et comment les éviter — Android Makers by droidcon
Apr 10, 2025Android Makers by droidcon

Les pièges courants dans les équipes techniques et comment les éviter

Android Makers

ReplaySlides
Seamless mobile real-time communication with WebRTC — devfest Toulouse
Nov 07, 2024devfest Toulouse

Seamless mobile real-time communication with WebRTC

devfest Toulouse

Replay
Seamless mobile real-time communication with WebRTC — droidcon London
Nov 01, 2024droidcon London

Seamless mobile real-time communication with WebRTC

droidcon London

Seamless mobile real-time communication with WebRTC — droidcon Lisbon
Sep 05, 2024droidcon Lisbon

Seamless mobile real-time communication with WebRTC

droidcon Lisbon

Seamless mobile real-time communication with WebRTC — droidcon SF
Jun 07, 2024droidcon SF

Seamless mobile real-time communication with WebRTC

droidcon SF

Creating a joystick in Jetpack Compose using Gesture API — Android Makers by droidcon
Apr 26, 2024Android Makers by droidcon

Creating a joystick in Jetpack Compose using Gesture API

Android Makers by droidcon

Slides
Creating a joystick in Jetpack Compose using Gesture API — devfest Ireland
Dec 02, 2023devfest Ireland

Creating a joystick in Jetpack Compose using Gesture API

devfest Ireland

I have a date — devfest Toulouse
Nov 16, 2023devfest Toulouse

I have a date

devfest Toulouse

Live-coding Ktor — devfest Strasbourg
Nov 15, 2023devfest Strasbourg

Live-coding Ktor

devfest Strasbourg

I have a date — droidcon London
Oct 26, 2023droidcon London

I have a date

Droidcon London

Replay
Discovering Material 3 for Android, I have a date — droidcon Berlin
Jul 05, 2023droidcon Berlin

Discovering Material 3 for Android, I have a date

Droidcon Berlin

ReplaySlides
I have a date — Android Makers by droidcon
Apr 27, 2023Android Makers by droidcon

I have a date

Android Makers

Replay
Live-coding Ktor — MiXiT
May 24, 2022MiXiT

Live-coding Ktor

MiXit

Replay
Live-coding Ktor — Android Makers by droidcon
Apr 28, 2022Android Makers by droidcon

Live-coding Ktor

Android Makers

Replay
Live-coding Ktor — Fosdem
Feb 05, 2022Fosdem

Live-coding Ktor

Fosdem

Replay
Virtual Android Makers — Virtual Android Makers
2020Virtual Android Makers

Virtual Android Makers

Designing effective navigation in Android — DevFest Brest
2019DevFest Brest

Designing effective navigation in Android

DevFest Brest

Quickly build your app alone with Firebase — Workshop Google
2019Workshop Google

Quickly build your app alone with Firebase

Workshop Google

Quickly build your app alone with Firebase — Android Makers
2018Android Makers

Quickly build your app alone with Firebase

Android Makers

How to effectively scan barcodes on Android — Lille Android User Group
2018Lille Android User Group

How to effectively scan barcodes on Android

Lille Android User Group

Android Makers — Android Makers
2017Android Makers

Android Makers

Ventures & experiments

Doppio

A boutique mobile agency focused on premium Android/KMP delivery.

Visit Doppio

Local Legends

An innovative way to plan trips with taste and context.

Discover Local Legends

Want to chat?

Let's talk ↗

Hands‑on mobile engineer and tech lead specializing in Android & Kotlin Multiplatform. I help teams ship polished apps faster through engineering, leadership, and audits.

© 2026 · Doppio Agency

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