Senior Frontend Engineer - Real-Time React/TypeScript

Fosh; Argentina; On-site; ARS 2,000,000 - 4,000,000; Full time

Job summary

Fosh is seeking a Senior JavaScript Developer to join our international team. You will be responsible for building scalable frontend solutions with React, TypeScript and CSS, participating in architecture, design, development, launching and maintenance of web applications.

You should be proactive, a strong team player, and fluent in English and Spanish. The role involves collaboration with product, design, QA and backend teams, and includes on-call responsibilities.

Qualifications

• 5+ years of modern frontend development experience with React, TypeScript, and CSS.
• Strong understanding of React patterns, hooks, lifecycle, and rendering behavior.
• Experience with state management tools (Redux Toolkit, Zustand) and web performance.
• Knowledge of SSR frameworks like Next.js and web standards including accessibility.
• Familiarity with CI/CD and automated testing (unit/integration).
• B2 English written and spoken.

Responsibilities

• Implement scalable, modular frontend solutions using React, TypeScript, and CSS with modern tooling.
• Build features that handle real-time data updates and complex state management.
• Work closely with product, design, quality and backend teams to deliver features with quality and speed.
• Write clean, maintainable code aligned with team standards and best practices.
• Contribute to the shared component library and design system with reusable components.
• Support code reviews within the team with constructive feedback.
• Participate in incident response and root cause analysis for production issues.
• Be part of the on-call shift.

Skills

React

TypeScript

CSS

Redux Toolkit

Zustand

Web performance

Accessibility (WCAG)

SSR/Next.js

Express.js

Node.js

Websocket

Svelte

Live data apps

CI/CD

English (B2)

Tools

Next.js

Express.js

socket.io

Job description

Fosh is seeking a Senior JavaScript Developer to join our international team. You will be responsible for building scalable frontend solutions with React, TypeScript and CSS, participating in architecture, design, development, launching and maintenance of web applications.

You should be proactive, a strong team player, and fluent in English and Spanish. The role involves collaboration with product, design, QA and backend teams, and includes on-call responsibilities.