Senior System Engineer

Description About the role Commit builds software products for clients across embedded, IoT, SaaS, AI/ML, e-commerce, mobile, and web. We’re looking for a Senior System Engineer with a strong mobile focus to sit at the intersection of analysis, design, and hands-on delivery — turning business and system requirements into clear architecture and detailed design, then helping build it. You’ll analyze requirements, own the High Level Design (HLD) and Low Level Design (LLD) — including mobile app architecture — and stay hands-on (~50% of your time) as a full-stack developer across a React, Node.js, React Native, and .NET stack, with React Native and mobile at its core. You’ll partner directly with clients (including large enterprise and banking environments). What you’ll do • Analyze system and business requirements — elicit, clarify, and structure them into clear, complete, and testable specifications. • Own the High Level Design (HLD), including mobile app architecture: system structure, components, integrations, data flows, and non-functional requirements. • Produce the Low Level Design (LLD): detailed module and API design, data models, and sequence flows, ready for implementation. • Stay hands-on (~50%): write production code full-stack — React, Node.js, .NET (C#), and React Native — with mobile at the center of what you build. • Partner with product, architects, developers, and QA to translate designs into delivery and keep requirements, design, and implementation aligned. • Uphold engineering standards: code reviews, testing, and secure-by-design practices across the solution. Requirements Must-have qualifications • 6+ years in software engineering, including hands-on system analysis and design. • Proven experience in system requirements analysis — eliciting, specifying, and structuring requirements for non-trivial systems. • Proven experience authoring HLD and LLD documents (architecture, component and API design, data models, integration and sequence diagrams). • Strong mobile development background — hands-on production experience with React Native and mobile app architecture (navigation, state management, offline/sync, performance, native-module integration, and app-store delivery). • Full-stack experience — production-level command across frontend (React), backend (Node.js and .NET / C#), and mobile (React Native), able to write production code, not just review it. • Solid grasp of software architecture patterns, API/service design, and system integration. • Strong handling of non-functional requirements — performance, security, scalability, and reliability —and secure-by-design practices. • Fluent with modern dev tooling: Git, JIRA, Jenkins. • Professional-level English. • Excellent interpersonal and communication skills. Nice to have • Native mobile experience (iOS / Swift, Android / Kotlin) alongside React Native. • Cloud experience (Azure / AWS) and microservices or messaging (e.g. gRPC, RabbitMQ, Kafka). • Familiarity with modeling and diagramming tools (e.g. UML, C4) for HLD/LLD. • Experience with AI-first development (Claude Code, Cursor). • Experience working in large organizations (e.g. banking / financial services).