Android Developer Internship - 6 months - Paris - F/H

  • Paris
  • Internship
  • Start Date: 08 December 2025
  • Apply Now

About

Founded in 2014, Karos is the European leader of carpooling for daily commutes. By changing at scale the way people commute, Karos is a major actor of the ecological transition.

The company now operates public carpooling services for more than 100 local authorities and 600 employers, with over 1.5 million users and rollouts across 6 European countries.

Since 2024, Karos is a mission-driven company (French “Société à mission”).

Our mission, written into our bylaws:

We are creating a new way of carpooling that is desirable and efficient, wherever it is useful, in order to improve everyday life and accelerate the ecological transition. As a trusted partner of key players in the territories, we are fighting to make carpooling a new standard for everyday transport.

Our impact is greatest where alternatives are lacking: daily commutes by private car.

It is on these trips — mainly home–work, peri-urban and rural — that we are committed, working with public and private stakeholders to change habits at scale.

Today, we are 100 team members, mainly based in France and Germany, and we are rapidly expanding across Europe (🇫🇷 🇩🇪 🇪🇸 🇨🇭 🇮🇹 🇳🇱).

Job Description

Are you passionate about Android development and ready to learn from experienced engineers building a product used every day by thousands?

Join Karos for a 6-month internship (Starting between December 2025 and March 2026) and help us make short-distance carpooling a true public transport alternative.

Your mission

Under the guidance of our Mobile team, you will:

Play a core role in our migration to Jetpack Compose, working on critical production code while leveraging cutting‑edge Android technologies.

Develop and improve features ensuring consistency, performance, and great UX.

Write and maintain unit tests to guarantee app reliability and scalability.

Contribute to code architecture decisions and continuous code quality improvements.

Collaborate with backend, design, and product teams to deliver impactful features for users and partners.

Learn and apply modern Android best practices in CI/CD, testing, and performance optimization.

Preferred Experience

What we’re looking for

Final-year Master’s student in Computer Science or related field at a school based in Île-de-France (required for the internship agreement).

Solid understanding of Kotlin and Android development fundamentals.

Familiarity with Jetpack Compose and Android architecture components (ViewModel, Fragment, StateFlow, etc.).

Interest or hands-on experience in automated testing tools (JUnit, Espresso, Maestro, etc.).

Curiosity to learn and contribute to a high-quality Android app used in real-world conditions.

Team spirit, open-mindedness, and motivation to contribute to projects with real-world impact.

What you’ll gain

By joining us, you’ll learn how to ship features from design to production in a fast-paced, supportive environment.

Hands-on experience in a dynamic and innovative startup environment.

Close collaboration with senior Android developers and product designers.

A deep dive into modern Android development with Jetpack Compose.

The opportunity to build and test features used daily by thousands of users.

A front-row view of how tech and mobility intersect to drive sustainable change.

The opportunity to experiment with Coding Agent (Claude Code) in a challenging production environment.

Recruitment Process

Initial interview (30 min) — Get to know the Engineering Manager and discuss your background and goals.

Technical interview (2 h) — Explore your understanding of Android, Compose, and testing practices through practical discussions.

Additional Information

  • Contract Type: Internship (Between 6 and 6 months)
  • Start Date: 08 December 2025
  • Location: Paris
  • Education Level: Master's Degree
  • Occasional remote authorized
  • Salary: 900€ / month