About the company At Auctane, we are united by a passion to help businesses deliver — whatever their size, wherever they are, and however they operate. We make it possible for businesses to meet the ever-changing requirements of their industry and customer expectations. Auctane products enable hundreds of thousands of businesses to annually mail and ship billions of items — over $200 billion worth — to recipients around the globe. The Auctane family of mailing and shipping software products includes ShipStation, Stamps.com, ShipStation API, Metapack, GlobalPost, and Packlink. Our partners include Amazon, UPS, USPS, eBay, BigCommerce, Shopify, WooCommerce, and Walmart. Our values Win as One. Delight Customers. Deliver Great Outcomes. About the role As a Senior Software Engineer, you will design, develop, and maintain complex user-facing applications and supporting backend services that align with business and technical requirements. You will take ownership of end-to-end feature implementation, optimizing client-side performance, accessibility, and user experience while ensuring robust API integration and data flow. You will troubleshoot technical challenges across the full application stack and collaborate with cross-functional teams (including UI/UX designers, product managers, and backend engineers) to deliver scalable, responsive solutions. Your role will involve contributing to technical discussions, refining best practices for modern frontend architecture and service integration, and supporting junior engineers through code reviews and knowledge sharing. We encourage our teams to embrace AI and make the most of our Claude Enterprise license to work smarter, experiment, and unlock new possibilities. We’re looking for a Senior Software Engineer who actively advocates for AI, is curious about its potential, and knows how to leverage AI tools to enhance their work, solve problems, and drive greater impact. This role is based in Madrid. What will you be doing? Contribute to end-to-end architecture discussions and develop software components aligned with functional and non-functional requirements. Creating high-quality, maintainable code in accordance with company best practices and standards. Participate in software testing, debugging, and optimization to ensure performance, scalability, and reliability. Develop and maintain cloud-based APIs, microservices, and intuitive user interfaces to deliver complete end-to-end features, as part of a collaborative engineering team. Support junior engineers through code reviews, pair programming, and sharing technical insights. Collaborate with the team to refine task prioritization and align work with project goals. Tackling complex problems requiring deep analysis and evaluation of diverse factors. Collaborating closely with product, UX, and infrastructure teams to ensure technical solutions meet both backend requirements and user needs. Communicate effectively with team members and external stakeholders to clarify requirements and share progress updates. Participate in technical discussions, advocate for improvements, and help resolve disagreements constructively. Providing timely, concise, and actionable feedback to team colleagues. Share knowledge through documentation, workshops, or informal team sessions. Assist in technical interviews to evaluate candidates for your team. Maintaining openness to communication with both local and external partners. Proactively learn new tools and practices spanning the full software lifecycle (e.g., modern frontend patterns, API design, DevOps, cloud services). What are we looking for? Experience in designing and developing modern web applications and interacting with backend services. Proficiency in frontend concepts, state management, algorithms, and data structures. Continuous focus on enhancing skills in software architecture design, and product development. Strong orientation toward task automation to save time and effort. Implementation of improvements and optimizations in daily operations. Designing and integrating RESTful/GraphQL APIs, managing seamless deployment pipelines for web applications. Ability to balance the demands of delivering high-quality software within tight deadlines. Proficiency in React or any other JS framework, with additional experience in any backend languages (e.g., C#, Node.js, or Java). Experience with Agile methodologies, responsive web design, and DevOps practices. Experience with cloud infrastructure automation. Knowledge and experience in use of design patterns (both object-oriented and frontend UI patterns). Fluency in English is required for this role. The tech stack React (or any other component-oriented JS framework) - Required TypeScript - Required C# .NET - Preferred RDBMS / SQL - Preferred Amazon Web Services - Preferred What do we offer? Clear and transparent compensation plan. The salary range goes from 47,000 € to 68,000 €. We will discuss the indicated range with you in the first recruiting call to ensure that we are on the same page. Flexible salary benefitsSave on personal income tax with Cobee for expenses like transport, restaurants, and kindergarten. Private health insuranceFree for all employees via Cigna, plus we cover 50% for your family members. Generous time offEnjoy 26 days of holiday per year (23 base days + your birthday off, Christmas Eve, and New Year’s Eve). Your gear, your choiceWhether you prefer Mac or Windows, or need an extra screen, we’ll make sure you’re set up for success from day one. Annual Salary ReviewWe’re committed to recognizing your professional growth. Every year, we review salaries to reflect your individual development, achievements, and impact on our business success. Grow your skillsWe offer up to €2000/year in training (certifications, conferences, workshops) to boost your growth—both technical and personal. Learning resourcesAccess internal and external training, including platforms like LinkedIn Learning, completely free. Holistic wellness programIncludes access to Wellhub, Curalinc (psychological support), Rocketlawyer (legal advice), and regular health webinars & challenges. Volunteer dayTake one day off a year to volunteer and give back. Bonus points for sharing pics on Slack! Free therapy vouchersBecause your mental health matters. Health & wellness supportGet up to €55/month to cover your gym or fitness classes (yoga, boxing, pilates, etc.). Weekly language classesImprove or learn a new language (English, Spanish, French, Italian, or German) in small groups with expert instructors—on us! Time for healthGet 8 hours per year for personal medical appointments and 10 hours per year to support your family’s medical needs. Work-life balanceWe’re flexible and people-first. We know life happens, and we aim to make work work for you. Inclusive, upbeat cultureNo suits here—just a welcoming, casual, and respectful space where diversity is celebrated, and you can be your full self. A global, multicultural teamWe’re made up of 20+ nationalities, speaking 10+ languages. All communication is in English, so everyone’s included. Packlink Pro discountEnjoy 99% off your personal shipments using our platform. Referral bonusesKnow someone amazing? Earn €1K–€3K when you refer candidates we hire—depending on the role. Central Madrid officeWhen you want a change of scenery, drop by our office in the heart of Madrid—free snacks and drinks included! Team eventsWe work hard and play hard with regular team-building activities and meetups. #LI-Hybrid
