UI Engineer

MARS Solutions Group; Glendale (WI); On-site; USD 70,000 - 95,000; Full time

Job summary

MARS Solutions Group is seeking a senior Front-End Engineer to build a shared UI framework for a BAS interface. You will develop React + TypeScript components within our design system, ensure accessibility, and align with UX designs and REST/streaming APIs.

You will be part of an Agile team, delivering a fixed-term project with a focus on performance, testing, and handover to the permanent staff after six months. Strong TS/React and debugging skills are essential.

Qualifications

• 4+ years building production web front ends with a related degree or equivalent.
• Strong TypeScript and React hooks, component composition, and rendering.
• Fluent HTML/CSS, responsive layout, theming, and CSS-in-JS or CSS modules.
• Experience building or extending a reusable component library or design system.
• Good debugging and performance analysis using browser dev tools.
• Understanding of CI/CD, small PRs, tests, and trunk-based development.

Responsibilities

• Build, extend, and harden reusable React + TS components in the design system.
• Implement BAS UI screens against UX designs and REST/streaming APIs.
• Ensure UI runs across edge/on-premises and cloud deployments.
• Write and maintain unit and component tests; contribute end-to-end coverage.
• Diagnose and fix front-end performance issues and memory use.
• Triage defects to verified fixes with root-cause notes.
• Provide component docs and usage examples for the permanent team.

Skills

React

TypeScript

HTML/CSS

UI/UX awareness

Agile/Scrum

CI/CD

Education

Bachelor's degree in Computer Science or Software Engineering

Tools

Jest

Vitest

React Testing Library

Job description

Why this role exists

We're building a shared UI Framework the component, theming, state, and API-access layer for our next-generation Building Automation System (BAS) interface, deployed to both edge/on-premises and cloud targets. This is a fixed-term engagement to add delivery capacity: you'll close a specific set of committed deliverables inside a 6-month window, working alongside our permanent engineers.

Scope of work

• Framework components. Build, extend, and harden reusable React + TypeScript components in our design system, including states, theming/tokens, keyboard interaction, and accessibility behavior.
• Feature surfaces. Implement assigned BAS UI screens and workflows against defined UX designs and REST/streaming APIs, including data fetching, caching, and error/offline/degraded-connectivity states.
• Cross-target correctness. Ensure the same UI runs correctly in both edge/on-premises and cloud-hosted deployments, on supported browsers and screen sizes.
• Test coverage. Write and maintain unit and component tests (Jest/Vitest + React Testing Library) and contribute automated end-to-end coverage for the flows you deliver.
• Performance. Diagnose and fix front-end performance issues bundle size, render cost, large data-set rendering, memory retention in long-running sessions.
• Defect burn-down. Take assigned defects from triage to verified fix, including root-cause notes.
• Documentation and handover. Leave component docs, usage examples, and decision notes sufficient for the permanent team to own the work after the engagement ends.

Team and delivery model

• You will join an established Agile scrum team as a full member alongside permanent staff.
• Delivery is assessed at team level: sprint commitments, flow of stories to done, and the quality of what the team ships. There is no separate individual scorecard.
• The team runs three-week sprints with backlog refinement, estimation, daily standup, sprint review and demo, and retrospective. Participation in all ceremonies is expected.
• Ramp expectation: development environment operational and a first reviewed pull request merged within your first sprint; contributing to the team's sprint commitment from the second sprint forward.
• Extension or conversion, if it happens, will be considered in the context of the team's outcomes and your contribution to them.

Required qualifications

• 4+ years building production web front ends, with a bachelor s degree in computer science or software engineering, or equivalent demonstrated experience.
• Deep, current TypeScript and React hooks, component composition, state management, and rendering behavior plus fluent modern HTML and CSS (responsive layout, theming, CSS-in-JS or CSS modules).
• Demonstrated experience building or extending a reusable component library or design system consumed by more than one application.
• Strong debugging and performance analysis skills using browser developer tools: profiling render cost, tracing network behavior, isolating memory growth.
• Clear understanding of the separation between application code, UI framework, and REST API, and the discipline to keep those boundaries intact.
• Effective in a CI/CD workflow: small pull requests, automated developer tests, trunk-based or short-lived branches, code review as a normal habit.
• Comfortable working across Windows and Linux development environments.
• Agile delivery habits: reliable estimates, visible progress, early escalation of blockers in daily standups and story refinement.

Preferred qualifications

• Accessibility implementation experience against WCAG 2.1 AA, including ARIA patterns and keyboard-only operation.
• Node.js/BFF or .NET/C# back-end familiarity sufficient to debug across the API boundary; Angular experience is also valued.
• Real-time or high-frequency data UIs WebSocket/SSE, virtualized tables, time-series charting.
• Experience with Chrome and Edge browser extension development, testing, and publishing.
• Building automation, industrial control, IoT, SCADA, or other operational-technology domains.