Senior Flutter Engineer (PLG) (Kotlin)

About the Role:

BOSS Revolution helps millions of people around the world stay connected with family and friends through international calling, mobile top-up, and money services. As a Senior Flutter Developer on the DTC Calling team you'll build and evolve the flagship BOSS Revolution app.

Your main direction is Product-Led Growth (PLG): the referral program (Refer-a-Friend), onboarding and activation funnels, promo and reward mechanics (loyalty and subscription offers, first-transfer and recharge bonuses, upsell offers), and the experiments that decide which of them ship. It is the main direction, not the only one: you'll take on any work the team owns — home, calling, money-transfer and top-up flows, subscriptions and payments — as the roadmap requires.

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 — and ship in short, instrumented iterations: hypothesis → flag → variant → metric → decision. The app also carries a native calling stack (SIP/VoIP on Android and iOS); experience there is welcome, not required.

What You'll Do:

Growth (main direction)

• Build growth mechanics end-to-end: referral flows (invite links, deferred deep links, reward tracking), onboarding & activation funnels, promo/reward dialogs and offer surfaces, in-app surveys — from a PRD with a success metric to a measured result in production.
• Run experiments as a habit: ship behind feature flags, wire variant assignment from our remote-config / A/B service (fixed-split and multi-armed-bandit tests) and Firebase Remote Config, tag events with test and variant, watch guardrail metrics, and remove the flag once the test is decided.
• Instrument and validate analytics: define and implement Amplitude/GA events and properties, keep the event taxonomy clean across releases, verify events before launch, and read funnel dashboards together with the PM and data team.
• Render server-driven promo content: integrate with our in-house campaign platform — targeted campaigns, remotely configurable copy and creatives, layout updates pushed from the backend in real time — with versioned fallbacks, so campaigns launch without an app release.
• Integrate third-party growth SDKs: attribution (AppsFlyer), Braze (push, content cards), ads (AdMob / AppLovin), payments and KYC vendors — mostly through Flutter plugins, occasionally extending them in Kotlin/Swift via platform channels.

Across the app and team

• Ship product features beyond growth: home screen, calling flows (Flutter UI over the native SIP stack), money-transfer and top-up flows, subscriptions and payments (card and wallet flows, Google/Apple Pay), country selection, chat and social features, performance and tech-debt work — the same standards, a different surface.
• Own features within our architecture: feature-first clean architecture, Bloc/Cubit state management, repositories, immutable state, Result-based error handling; migrate legacy Provider/ViewModel code in the modules you touch (e.g. the referral module) to the current patterns.
• Work at real scale: a Melos-managed monorepo with 100+ packages, strict dependency hierarchy, code generation (json_serializable / freezed), a shared design system, and a 90% diff-coverage gate enforced per package in CI (bloc_test + mocktail).
• Keep releases healthy: trunk-based development, ~2 releases a month through GitHub Actions and Fastlane, Crashlytics plus product-metric monitoring, staged rollouts and kill-switches for risky changes.
• Collaborate cross-functionally: with product managers (growth and core product), backend engineers (campaign, config and A/B services), data & BI, marketing (Braze campaigns) and QA — and push back on asks that cannot be measured.
• Use AI-assisted development as part of the everyday workflow: Cursor / Claude Code / Copilot with in-repo prompts, agents and MCP integrations.

We're Looking For:

• 5+ years building mobile apps, including 3+ years with Flutter in production.
• Strong Flutter/Dart: Bloc/Cubit or comparable structured state management, async programming and isolates, code generation, dependency injection, clean architecture and modularization.
• Hands-on, experiment-driven product development: feature flags and remote config (Firebase Remote Config, LaunchDarkly, Statsig, GrowthBook or an in-house service), A/B rollout mechanics (staged rollout, sticky assignment, kill-switch) and analytics instrumentation (Amplitude, Mixpanel, GA or similar) — including knowing how your experiments ended.
• Deep linking, including deferred deep links and App Links / Universal Links setup; understanding of attribution flows.
• Working knowledge of native Android (Kotlin) and/or iOS (Swift) at the level of platform-channel and SDK integrations.
• Strong testing culture: unit and bloc tests with mocked collaborators, deterministic tests, comfortable working under coverage gates.
• Full lifecycle experience: Git, CI/CD (e.g. GitHub Actions), code signing, store deployment, post-release monitoring.
• Product mindset: can work from a PRD with success metrics, propose instrumentation and guardrails, and explain trade-offs to non-engineers.
• English: Upper-Intermediate or higher.

It Would Be a Plus:

• Time on a dedicated growth or monetization team: referral programs, onboarding optimization, paywalls / subscriptions, retention work, multi-armed bandits.
• Attribution and marketing SDKs by name: AppsFlyer, Kochava, Adjust, Branch; Braze, Iterable, CleverTap.
• Server-driven UI or remotely configurable content systems.
• Payments and subscriptions on mobile: card flows, 3DS, in-app purchases, Google/Apple Pay.
• VoIP / real-time communication: SIP, WebRTC, CallKit / Telecom framework, push-triggered call handling, audio session management.
• Large monorepos (melos, Mason, Dart workspaces); migrating legacy state-management patterns.
• Beyond mobile: backend / BFF for growth features, data pipelines, observability.
• Telecom, fintech or other regulated consumer products (KYC, fraud vendors).
• Comfort with AI-assisted development tooling.

We offer you:

• Modern office with free parking in the very center of Minsk.

• Remote/ hybrid work opportunity!

• An exciting and challenging job with talented people around.

• Competitive salary and growth opportunities.

• Really good hardware.

• 26 vacation days & 5 fully covered sick days without sick leave required per year.

• Compensation for professional training, seminars, and conferences.

• Sports activities reimbursement and loyalty program.

• Medical insurance and sports reimbursement.

• Referral program – get rewarded for helping us grow the team with talented people.

• Company-supported English classes to enhance your professional growth.

  We offer you:

• Modern office with free parking in the very center of Minsk.

• Remote/ hybrid work opportunity!

• An exciting and challenging job with talented people around.

• Competitive salary and growth opportunities.

• Really good hardware.

• 26 vacation days & 5 fully covered sick days without sick leave required per year.

• Compensation for professional training, seminars, and conferences.

• Sports activities reimbursement and loyalty program.

• Medical insurance and sports reimbursement.

• Referral program – get rewarded for helping us grow the team with talented people.

• Company-supported English classes to enhance your professional growth.

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!