This job is no longer available
This job expired on 17/08/2026. It no longer accepts applications.
Mid-Level Front-End Developer – React.js & jQuery Migration
Trinetix · Madrid
Job description
About the role
We are looking for a motivated Mid-Level Front-End Developer to join our dynamic team. You will focus on converting legacy jQuery applications into modern React solutions while also building new React applications from scratch. The role involves close collaboration with designers, back‑end developers, and junior team members.
Key responsibilities
- Migrate existing jQuery‑based applications to React, preserving functionality and performance.
- Develop new, interactive React applications in partnership with UI/UX designers and back‑end engineers.
- Write clean, modular, and reusable code and optimise applications for speed, scalability and responsiveness.
- Collaborate with UX/UI designers to implement visually appealing interfaces.
- Integrate RESTful APIs and ensure smooth data flow between front‑end and back‑end.
- Create and maintain unit and integration tests for React components.
- Use Git for version control, following established workflows for code reviews.
- Mentor junior developers and share best practices in React and JavaScript.
- Document development processes, coding standards and technical decisions.
Required profile
- 2‑4 years of experience as a front‑end developer with a focus on JavaScript, React and jQuery.
- Strong grasp of modern JavaScript (ES6+), including closures, promises and asynchronous programming.
- Hands‑on experience with both class‑based and functional React components, hooks and state management.
- Solid understanding of jQuery and experience migrating legacy codebases.
- Familiarity with front‑end build tools such as Webpack, Babel and NPM.
- Experience working with RESTful APIs and tools like fetch or axios.
- Good knowledge of HTML5, CSS3 and responsive design principles.
- Proficiency with Git and standard version‑control workflows.
Required skills
- JavaScript (ES6+)
- React (class and functional components, hooks)
- jQuery
- HTML5
- CSS3
- Webpack
- Babel
- NPM
- RESTful APIs (fetch, axios)
- Git
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Trinetix
Madrid
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