Senior Software Developer Node.js / AWS / React London (Hybrid, 3 days onsite) Are you the kind of engineer who enjoys taking something fast-and-scrappy and turning it into something scalable, elegant, and genuinely robust? This is a chance to join a small, but ambitious tech-for-good / IoT startup based in the London City Centre that s building products to make sense of massive data streams. You ll be part of a tight-knit team (around ten people total, five engineers), working on a genuinely greenfield platform with a modern stack and zero legacy The focus now is on maturing the codebase re-architecting, refactoring, testing, and scaling. You ll play a key role in helping the team evolve from early-stage speed to long-term stability, with the freedom to influence both product direction and engineering quality What you ll be doing: Building and scaling a Node.js application that sits at the core of the product Designing and implementing new features for different sectors and use cases Helping drive improvements in code quality, architecture, and testing practices Working closely with product and engineering to prioritise, shape, and deliver features Introducing best practices and guiding a shift towards cleaner, more maintainable code What we re looking for: Strong hands-on experience with Node.js Comfortable working across or picking up other tech as needed ie AWS, React etc (If you have experience with AWS and React, that is a bonus) Enthusiasm for writing clean, t