Frontend Engineer (JavaScript + Custom Framework)

Frontend Engineer (JavaScript + Custom Framework)Location: LATAM, RemoteCompany: Base LabsPosition type: Full-timeWe’re looking for a Senior Frontend Developer who’s passionate about clean code, architecture, and performance. You’ll join a small, focused team working on a high-traffic e-commerce using a custom framework based on Backbone.js, with Node.js and Express for some backend tasks.We do not use React, Vue, or Angular. This project requires strong JavaScript fundamentals and a curious mindset to navigate and understand a large, actively evolving codebase with limited documentation.About the role:You’ll work on an e-commerce platform with millions of monthly visits.You’ll be part of a technical team that prioritizes performance and stability.We use an in-house framework based on Backbone.js, server-side rendering with Node.js, and orchestration with Nginx and Express.Work distribution: 80% frontend / 20% backend.You’ll need to review, understand, and propose improvements directly in the source code. Documentation is limited, so your analytical skills and technical curiosity will be key.Requirements:4+ years of professional frontend development experience.Advanced proficiency in JavaScript and TypeScript.Solid experience with Node.js, Express, and server-side rendering concepts.Knowledge of relational databases and integration with REST APIs (JSON).Fluent English, written and conversational (day-to-day work is 100% in English).Knowledge and practical application of principles like SOLID, ACID, and frontend/backend architecture best practices.Nice to haveExperience working on legacy products or codebases with little/no documentation.You’re self-taught and excited to understand how things work.You’re not afraid to dive into complex code and leave it better than you found it.