Senior System Engineer

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).