Mobile Engineer

Cosmose, Inc.; Warszawa; On-site; PLN 180,000 - 280,000; Full time

Benefits offered by this job

Stock options

Flat structure

Big scale startup culture

Job summary

Cosmose AI in Warsaw is seeking a Mid-level Mobile Engineer to help build ambitious applications and SDKs powering Cosmose technology on millions of devices.

Bring 3+ years of mobile experience, strong Kotlin and Android skills, and a passion for scalable, high-performance software. Join a fast-paced startup culture with a world-class engineering team.

This role offers opportunities to impact product direction and collaborate across disciplines.

Qualifications

• 3+ years designing, developing, and deploying mobile apps.
• Strong Kotlin, Kotlin Multiplatform, and Android native expertise.
• Experience with Flutter and iOS is a plus.
• Familiarity with AOSP architecture is beneficial.

Responsibilities

• Design, develop, and deploy high-quality mobile applications.
• Optimize performance and user experience.
• Create and maintain automated tests for mobile apps.
• Contribute to SDK development for third-party integrations.
• Collaborate with cross-functional teams and business stakeholders.
• Share knowledge and mentor teammates.

Skills

Mobile development

Kotlin

Kotlin Multiplatform

Android native

Flutter

iOS

Job description

Unicorn Foundations: At Cosmose AI, we’re building smart, innovative technology that’s redefining digital marketing and content distribution. Since launching in 2014, we’ve gone from transforming offline shopping to powering personalized content experiences through AI. Founded by Miron Mironiuk, our journey began with one bold idea — and it has grown into a feature that caters to what people care about most, right from their lock screens.

Exceptional Engineering: Our engineering team is far from average; it's a powerhouse of talent. Comprising former FAANG employees and programming champions, they bring deep expertise and a shared commitment to building world‑class products. Our strength lies in engineering solutions that leverage the power of AI, Data, and distributed computing. We thrive in a fast‑paced startup environment, where agility, creativity, and quality drive everything we do.

Global Presence, Local Innovation: Cosmose AI is a global company with a presence in 8 countries, transforming content engagement through cutting‑edge technology. Our flagship product, KAIKAI Lock Screen, delivers AI‑powered, personalized content to users worldwide, unlocking new and exciting opportunities for product placement.

We are seeking a Mid‑level Mobile Engineer to join our dynamic and rapidly expanding team. In this role, you will play a crucial part in building our innovative products, including applications and SDKs that will power Cosmose technology on millions of devices from our partners. If you are passionate about mobile development, enjoy solving complex challenges, and are excited to work on projects that reach a wide audience, we would love to hear from you.

Why us?

• Big Scale & Startup Culture: Join a company that combines the scale of a major player with the agility and innovation of a startup
• Exceptional Team: Collaborate with a team of former employees from tech giants like Google, Facebook, ByteDance, and Microsoft, as well as ACM ICPC programming champions
• Stock Options: As we grow and succeed together, you’ll have the chance to benefit from it
• Flat Structure: Enjoy a flat organizational structure that promotes collaboration and provides opportunities to learn from seasoned technical leadership
• Challenging Engineering Problems: Tackle challenging engineering problems in areas of high‑performance computing, distributed systems, blockchain, and AI/ML

What You’ll Do

• Mobile App Development: Design, develop, and deploy high‑quality mobile applications that deliver exceptional user experiences.
• App Optimization: Ensure our mobile apps run efficiently and effectively.
• Automated Testing: Implement comprehensive automated tests to maintain the robustness and reliability of our mobile applications.
• Innovation: Contribute creative ideas and solutions to enhance our products and stay ahead of market trends.
• SDK Development: Collaborate on the development and maintenance of our Mobile SDKs to support third‑party integrations.
• Business Support: Assist our business teams with technical expertise and solutions to meet their mobile‑related needs.
• Knowledge Sharing: Share your knowledge and expertise with the team to foster a collaborative, learning‑focused environment.

What You’ll Need

• Minimum 3 years of experience in designing, developing, and deploying mobile applications, with a strong understanding of key concepts and best practices.
• Experience developing mobile applications using Kotlin, with hands‑on experience in Kotlin Multiplatform (KMP). Strong knowledge of native Android development is required. Flutter and iOS experience is nice to have.
• Understanding some of the AOSP (Android Open Source Project) architecture and Android OS internals will be a strong advantage.
• A passion for staying up-to-date with the latest advancements in mobile technologies and a desire to push the boundaries of what’s possible.
• Ability and confidence to communicate effectively within the team (Polish and English are required).
• Proven relevant experience in the Android or cross‑platform mobile ecosystem will be a plus!

What You’ll Enjoy

Cosmose provides employees with a great platform to immerse and learn about the most exciting, innovative, and disruptive technologies in offline behavior solutions, unveiling untapped opportunities and profits in the industry. The company constantly innovates to invent and apply world‑class technologies with a rockstar engineering team, including four world championship programming medalists. You’ll be working with a strong leadership team backed by experience from various key strategic areas and many other driven & intelligent people across the company. Cosmose is a place where great culture and goals unite departments and individuals to achieve big milestones together.

We’re building something big—and we’re just getting started.

If you’re excited about shaping the future of AI‑powered mobile content, we’d love to meet you.

Be part of the Cosmose story. Apply now!