Senior Flutter Software Engineer

IDT; Belgrade; On-site; EUR 70,000 - 100,000; Full time

Benefits offered by this job

Remote work options

On-site options

Long-term growth

Competitive salary

Hardware provided

English courses

Job summary

IDT Corporation is seeking a Senior Flutter Developer for the DTC Calling team to build the flagship BOSS Revolution app, a large Flutter product with a deep native calling stack (SIP/VoIP). You’ll work in a massive Flutter codebase with platform channels to Kotlin/Swift, contributing to architecture, testing, and CI/CD pipelines.

Ideal candidates bring 5+ years in mobile apps, 3+ years Flutter, native mobile experience, and strong English.

Qualifications

• 5+ years of experience building large mobile apps with 3+ years in Flutter.
• Strong proficiency in Flutter/Dart and state management.
• Hands-on native mobile development experience (Kotlin/Swift) with Flutter integration via platform channels.

Responsibilities

• Design and build high‑performance features in Flutter/Dart while extending the native calling stack.
• Own features end‑to‑end with clean architecture and high test coverage.
• Collaborate with product, backend, QA and design in a cross‑functional team.

Skills

Flutter/Dart

Mobile development

Unit testing

CI/CD

Native Android/iOS

Tools

Kotlin

Swift

Git

Job description

BOSS Revolution helps millions of people across the world stay connected with family and friends — through international calling, mobile top-up, and money services. As a Senior Flutter Developer on our DTC Calling team, you'll build and evolve the flagship BOSS Revolution app: a large-scale Flutter product with a deep native calling stack (SIP/VoIP on Android and iOS) at its core.

You’ll work in one of the largest Flutter codebases in production — a monorepo of 100+ internal packages, feature‑first clean architecture, and a strong engineering culture around code quality, testing, and automation.

What You’ll Do

• Hybrid development: Design and build high‑performance features in Flutter/Dart, while maintaining and extending the native calling stack — SIP clients, audio handling, CallKit/ConnectionService integration — in Kotlin and Swift, connected via platform channels.
• Own features end‑to‑end within our feature‑first clean architecture: Bloc/Cubit state management, repositories, immutable state, and 90%+ unit‑test coverage on business logic.
• Work at real scale: a melos‑managed monorepo with 100+ packages, strict dependency hierarchy, code generation (freezed / json_serializable), and shared design system.
• Ensure reliability of a real‑time product: monitor releases with Crashlytics and analytics pipelines, investigate call‑quality and stability issues, and drive performance optimization.
• Contribute to the overall architecture and technical strategy of our mobile platform — from package design to migration of legacy patterns to the current architecture.
• Collaborate closely with product managers, backend engineers, QA, and designers as part of a cross‑functional product team.
• Improve our engineering toolchain: GitHub Actions CI/CD, automated store/TestFlight releases, diff‑coverage gates, and code‑quality automation.

We’re Looking For

• 5+ years of experience building large‑scale mobile apps, including 3+ years with Flutter.
• Strong proficiency in Flutter/Dart with deep understanding of the ecosystem: Bloc/Cubit (or comparable state management), asynchronous programming and isolates, code generation, and dependency injection.
• Hands‑on experience with native mobile development (Kotlin/Android and/or Swift/iOS) and integrating native code with Flutter via platform channels.
• Solid understanding of mobile architecture patterns (clean architecture, modularization), performance optimization, and security best practices.
• Strong testing culture: unit and bloc testing with mocked collaborators, deterministic tests, working under coverage gates.
• Experience with the full mobile app development lifecycle — from concept to production and post‑release monitoring — including Git, CI/CD pipelines (e.g., GitHub Actions), code signing, and deployment automation to the App Store and Google Play.
• English: Upper‑Intermediate or higher.

It Would Be a Plus

• Experience with VoIP/real‑time communication: SIP, WebRTC, CallKit / Telecom framework, push‑triggered call handling, audio session management.
• Experience working in large monorepos (melos, Mason, or similar tooling).
• Knowledge and experience beyond the mobile stack (backend, infrastructure, observability).
• Domain experience in telecom, fintech, or other regulated consumer products.

We are pleased to offer you

• Remote b2b (Georgia‑Moldova) or on‑site employment (Belarus‑Moldova) work opportunity!
• Stable job with long‑term growth perspective.
• Competitive salary with annual performance review.
• Really good hardware.
• An exciting and challenging job with talented people around.
• Continuous learning and career growth opportunities.
• Compensation for professional training, seminars, and conferences.
• Referral program – get rewarded for helping us grow the team with talented people.
• Company‑supported English classes to enhance your professional growth.
• More perks for the Minsk and Chisinau office employees.

A few words about us

IDT Corporation is a global communications company founded in 1990 and headquartered in Newark, New Jersey. We are industry leaders in prepaid communication and payment services and one of the largest international voice carriers. We are listed on the NYSE, employ over 1800 people across 20 countries, and have over $1.5 billion in revenues.

IDT is not another big IT corporation — we encourage and support in‑house entrepreneurs in developing their ideas into business actions.

Our flagship brand, BOSS Revolution, offers Money Transfer, International Calling, and Mobile Top‑Up services and supports IDT’s mission of enabling people to keep in touch and share resources with family and friends worldwide.

If you’re looking for a company that will give you the maximum flexibility in choosing a location to work, this opportunity is for you!