Senior Front End Developer at Sysmind Moline, IL

Ellenco Estágios e Treinamentos; Moline (IL); On-site; USD 140,000 - 170,000; Full time

Job summary

Ellenco Estágios e Treinamentos in Illinois seeks an experienced Senior Frontend Developer with 8+ years specializing in JavaScript, React.js, and API integration to build scalable, high‑performance user interfaces.

You will collaborate with cross‑functional teams to deliver end‑to‑end web solutions, translate UI/UX wireframes, and ensure accessibility and quality through tests and reviews.

Qualifications

• 6+ years of frontend development experience.
• Strong proficiency in JavaScript (ES6+).
• Robust React.js experience and component design.
• API integration with RESTful or GraphQL services.
• Familiarity with GitHub for version control.
• Knowledge of basic UX principles.

Responsibilities

• Develop, enhance, and maintain web applications using JavaScript (ES6+) and React.js.
• Build reusable UI components and scalable front‑end architecture.
• Integrate frontend with RESTful or GraphQL APIs for dynamic data flow.
• Collaborate with designers to translate UI/UX wireframes into interfaces.
• Optimize performance, responsiveness, and cross‑browser compatibility.
• Debug UI issues across web applications and fix defects.
• Manage application state using Redux or Context API.
• Write unit tests with Jest or React Testing Library.
• Participate in code reviews and maintain coding standards.

Skills

JavaScript

React.js

API integration

Redux/Context API

Unit testing (Jest)

GitHub/Git

UX principles

Tools

Jest

React Testing Library

Git

Job description

We are looking for an experienced Senior Frontend Developer with 8+ years of experience specializing in JavaScript, React.js, and API integration. The candidate will be responsible for building scalable, high‑performance user interfaces and collaborating with cross‑functional teams to deliver end‑to‑end web solutions.

• Develop, enhance, and maintain web applications using JavaScript (ES6+) and React.js.
• Build reusable UI components and implement clean, maintainable front‑end architecture.
• Integrate frontend applications with RESTful APIs / GraphQL APIs for dynamic data flow.
• Work closely with designers to translate UI/UX wireframes into functional interfaces.
• Optimize applications for performance, responsiveness, and cross‑browser compatibility.
• Debug and resolve UI/functional issues across web applications.
• Manage application state using Redux, Context API, or other state management tools.
• Write unit tests using tools such as Jest or React Testing Library.
• Use Git/GitHub for version control, branching, and collaborative development.
• Ensure the application adheres to basic UX principles for usability and accessibility.
• Participate in code reviews to maintain coding quality and standards.

Minimum Years of Experience:

• 6+ years

Must Have Skills:

• JavaScript or other equivalent front end programming languages
• Use of GitHub
• Basic UX principles
• React.js
• API integration