Internship Flutter App Developer Jobs in Fairfield, CA

The opportunity

We are looking for a Principal Mobile App Developer to architect and lead the development of a standalone B2C mobile application. This app will serve as a premier destination for players to discover new games, track their playtime and milestones, and earn real-world rewards. You will be building the highly gamified "storefront" that sits on top of Unity's massive backend ML and data infrastructure.

If you have built massive consumer apps featuring real-time ledgers, gamified progression systems, and flawless, 60fps UIs, this is a rare opportunity to build a product from the ground up with the backing of the biggest player in mobile gaming.

What you'll be doing

• Lead the Architecture: Design and architect the mobile client (iOS/Android) for a greenfield consumer rewards application. You will make the foundational decisions on the tech stack, state management, and app architecture.
• Build the Consumer Experience: Develop highly engaging, gamified UI/UX components-including daily streak mechanics, dynamic offer walls, progress trackers, and real-time wallet balances.
• Integrate at Scale: Connect the consumer app directly into Unity's backend event-pipelines and ML attribution models (optimizing for expected user value, e.g., E[V] and retention probability.
• Manage Virtual Economies: Architect robust on-device state management that handles virtual currencies, ledger updates, and offline/online syncing without dropping a single transaction.
• Anti-Fraud & Attribution: Work alongside our ML and backend teams to implement secure, tamper-proof event tracking to prevent device farming and exploit loops.
• Technical Leadership: Mentor senior mobile engineers, set the standard for code quality, and define the CI/CD and release pipelines for a high-frequency update cycle.

What we're looking for

• Deep Mobile Expertise: 8+ years of experience building native (Swift/Kotlin) or high-performance cross-platform (React Native/Flutter) consumer mobile applications at scale.
• Consumer Gamification Experience: Proven track record building apps with high DAU/MAU that rely on gamification, loyalty programs, or fintech/wallet features.
• Architectural Mastery: Deep understanding of modern mobile architecture patterns (MVVM, Clean Architecture, VIPER), memory management, and performance profiling.
• Event-Driven Systems: Experience handling complex asynchronous data streams, real-time websocket connections, and local persistence for offline-first capabilities.
• UI/UX Obsession: You care deeply about micro-interactions, animations, and how an app feels in the user's hands.

You might also have

• Previous experience at a pure-play consumer rewards company (e.g., Mistplay, Fetch, Ibotta, JustPlay) or a consumer fintech app with heavy gamification.
• Familiarity with mobile attribution platforms (AppsFlyer, Adjust, Singular) and how playtime/event milestones are tracked under the hood.
• A passion for mobile gaming and an understanding of what drives player retention.

Additional information

• Relocation support is not available for this position

This range reflects the anticipated base salary for this position. Beyond base salary, this role may be eligible for equity awards and participation in our company incentive plans (such as annual discretionary bonuses or sales commissions). The final offer amount will depend on several factors, including geographic location and the candidate's relevant experience, professional background, and skill set.

Benefits

At Unity, we want our team members to thrive. We offer a wide range of benefits designed to support well-being and work-life balance.

Please note: Benefits eligibility, specific offerings, and coverage vary based on the country and employment status.

While specific benefits vary, here are some of the ways we strive to take care of our eligible team members globally: Comprehensive health, life, and disability insurance | Commute subsidy | Employee stock ownership | Competitive retirement/pension plans | Generous vacation and personal days | Support for new parents through leave and family-care programs | Office food snacks | Mental Health and Wellbeing programs and support | Employee Resource Groups | Global Employee Assistance Program | Training and development programs | Volunteering and donation matching program

Life at Unity

Unity [NYSE: U] is the world's leading game engine, powering play for more than 3 billion consumers each month. The top mobile games in the world, the most played PC indie titles, the most innovative console games, and virtually all of the top XR and Web Games are developed, deployed, and grown in Unity. Unity also enables teams across industries like automotive, manufacturing, and healthcare to design, simulate, and collaborate in 3D - closing the gap between ideas and reality. For more information, please visit www.unity.com.

Unity is a proud equal opportunity employer. We are committed to fostering an inclusive, innovative environment and celebrate our employees across age, race, color, ancestry, national origin, religion, disability, sex, gender identity or expression, sexual orientation, or any other protected status in accordance with applicable law. Our differences are strengths that enable us to support the growing and evolving needs of our customers, partners, and collaborators. If you have a disability that means there are preparations or accommodations we can make to help ensure you have a comfortable and positive interview experience, please fill out this form to let us know.

Pursuant to the San Francisco Fair Chance Ordinance, we will consider for employment qualified applicants with arrest and conviction records.

This position requires the incumbent to have a sufficient knowledge of English to have professional verbal and written exchanges in this language since the performance of the duties related to this position requires frequent and regular communication with colleagues and partners located worldwide and whose common language is English.

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