Senior Front-End Software Engineer

SOMERSET STAFFING; Los Angeles (CA); On-site; USD 140,000 - 180,000; Full time

Job summary

SOMERSET STAFFING is seeking a Senior Front-End Software Engineer to help build and optimize a streaming application across devices. You will focus on performance and keep the app fast and stable on resource-constrained devices.

You’ll contribute to scalable UI components and robust front-end architecture. You will implement UI with React 18 and TypeScript, manage state with Redux RTK, and address memory leaks, startup times, and rendering bottlenecks in a cross-functional team.

Qualifications

• Strong experience with React and TypeScript.
• Experience with Redux and RTK.
• Familiarity with React Router for client-side routing.
• Solid understanding of front-end fundamentals (HTML, CSS, JavaScript).
• Experience with performance optimization and profiling.
• Understanding of large SPA performance bottlenecks.
• Ability to work collaboratively in a cross-functional team.

Responsibilities

• Build and maintain front-end features with React 18 and TypeScript.
• Develop predictable state management using Redux/RTK.
• Identify, measure, and resolve rendering and memory bottlenecks.
• Debug memory leaks in long-running applications.

Skills

React

TypeScript

Redux

Redux Toolkit

React Router

HTML/CSS/JavaScript

Performance optimization

Cross-functional collaboration

Memory management

Tools

Vitest

Playwright

Job description

• We’re looking for a Senior Front-End Software Engineer to help build and optimize a streaming application used across various devices.
• This role is ideal for someone who cares deeply about performance and knows how to keep complex applications fast and stable on resource‑constrained devices.

What You’ll Do:

• Build and maintain front-end features using React 18 and TypeScript
• Develop predictable and maintainable state management using Redux and Redux Toolkit (RTK)
• Identify, measure, and resolve performance bottlenecks related to rendering, memory usage, and application startup
• Debug and mitigate JavaScript memory leaks in long-running applications

Required Qualifications:

• Strong experience with React and TypeScript
• Experience managing application state with Redux and RTK
• Familiarity with client‑side routing patterns using React Router
• Solid understanding of front‑end fundamentals (HTML, CSS, modern JavaScript)
• Experience with performance optimization - debugging, measurement, and implementation (e.g., profiling, monitoring, or performance tooling)
• Understanding of browser internals, rendering behaviour, or performance bottlenecks in large SPAs
• Ability to work collaboratively in a cross‑functional team

For tech stack, this is what they currently use so understanding of these would be good:

• React 18.2.0 & TypeScript 5.9.2
• State Mgmt.: Redux, RTK
• Routing: React Router
• Testing: Vitest, Playwright (familiarity is fine)
• Preferred: Someone who has experience in app performance, measuring it, looking into things like debugging JS memory leaks.

Skills

Mandatory Skills :

React 18 and TypeScript, HTML/HTML5, React, Redux and Redux Toolkit (RTK)

Required Skills :

Basic Qualification :

Additional Skills :

Background Check : No

Drug Screen : No