Senior Back-end Developer Python - CDI - Barcelona
About this role
<p><span>Since 2015, papernest has been transforming the way people manage their contracts, making subscription, management, and switching simple through one smart, intuitive platform.</span></p><p><span>We have supported more than 2 million customers across France, Spain, and Italy. Along the way, we have continued to invest in new verticals, establishing papernest as a high-performing, innovative, and competitive scale-up in a fast-growing market.</span></p><p><span>With over 900 employees, we are strengthening our position as a European market leader.</span></p><p>As a Senior Backend Engineer, you will play a key role in strengthening and scaling the technical foundations of our Spanish market operations.</p><p></p><h3><strong>Your responsibilities:</strong></h3><p>You will be responsible for designing, building, and evolving backend systems that support business growth, operational efficiency, and long-term scalability. Acting as a bridge between business operations and technology, you will translate operational requirements into reliable, maintainable, and scalable software solutions.</p><p>In a dynamic and fast-evolving environment, you will bring structure and engineering rigor. You will contribute to architectural decisions, establish best practices, and ensure that backend systems are resilient, performant, and aligned with the company’s strategic objectives.</p><p>Your mission includes:</p><ul><li><p>Designing and implementing scalable backend services and APIs</p></li><li><p>Improving system reliability, performance, and maintainability</p></li><li><p>Partnering closely with operations and business stakeholders to understand evolving needs</p></li><li><p>Driving technical excellence and reducing technical debt through pragmatic decision-making</p></li><li><p>Contributing to architectural standards and long-term platform strategy</p></li><li><p>Supporting the scalability of our Spanish market by building robust, future-proof infrastructure</p></li></ul><p>This role requires a hands-on senior engineer who combines strong technical expertise with business awareness, thrives in evolving environments, and takes ownership of delivering sustainable solutions that enable growth.</p><p><br></p><h4><strong>Your profile:</strong></h4><ul><li><p>Bachelor’s or Master’s degree in Computer Science, Software Engineering, or equivalent practical experience.</p></li><li><p>5+ years of backend development experience, including senior-level ownership of architecture and integrations.</p></li></ul><p><strong>Technical Expertise:</strong></p><ul><li><p>Senior-level expertise in Python (Django/FastAPI), including event-driven or asynchronous architectures.</p></li><li><p>Strong experience managing complex API integrations and debugging data inconsistencies across multiple external services.</p></li><li><p>Ability to reverse engineer semi-technical workflows (“shadow IT”) to understand business logic before leading refactoring.</p></li></ul><p><strong>Your Strengths:</strong></p><ul><li><p>Strong analytical and problem-solving mindset.</p></li><li><p>Pragmatic and structured approach in fast-moving environments.</p></li><li><p>Fast learner of business domains with the ability to bridge technical and operational topics.</p></li></ul><p><br>Professional English required; Spanish is a plus.</p><p></p><h4><strong>What We Offer You:</strong></h4><p>Evolve in an international and inclusive environment: Everyone has a place at papernest, and with over 46 nationalities, it’s common to start a sentence in French and finish it in English or Spanish!</p><p>💸 <strong>Compensation:</strong> receive Subscription Bonuses for Company Creators (BSPCE) from your first day, in line with company regulations.</p><p>🏆 <strong>Benefits:</strong> as a provider of home insurance and green energy, we offer our employees attractive deals. After all, it shouldn’t be just our clients who benefit!</p><p>🩺 <strong>Health:</strong> enjoy mutual health insurance through <a target="_blank" href="https://alan.com/">Alan</a>, offering simple, paper-free management of your healthcare expenses, with 50% covered by papernest.</p><p>🍽️ <strong>Meals:&