We make it possible for businesses to meet the ever-changing requirements of their industry and customer expectations. The Auctane family of mailing and shipping software products includes ShipStation, Stamps.Our partners include Amazon, UPS, USPS, eBay, BigCommerce, Shopify, WooCommerce, and Walmart. 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. 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.





Share knowledge through documentation, workshops, or informal team sessions. Maintaining openness to communication with both local and external partners. Proactively learn new tools and practices spanning the full software lifecycle (e.modern frontend patterns, API design, DevOps, cloud services).

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.

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.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. React (or any other component-oriented JS framework) - Required TypeScript - Required RDBMS / SQL - Preferred Amazon Web Services - Preferred Save on personal income tax with Cobee for expenses like transport, restaurants, and kindergarten.

Private health insurance Enjoy 26 days of holiday per year (23 base days + your birthday off , Christmas Eve, and New Year's Eve). Whether you prefer Mac or Windows , or need an extra screen, we'll make sure you're set up for success from day one.

We offer up to €2000/year in training (certifications, conferences, workshops) to boost your growth—both technical and personal. Access internal and external training , including platforms like LinkedIn Learning , completely free. Includes access to Wellhub, Curalinc (psychological support), Rocketlawyer (legal advice), and regular health webinars & challenges. Take one day off a year to volunteer and give back. Bonus points for sharing pics on Slack!

📌 (Senior) IT Software Engineer H/F (Madrid)
🏢 Auctane
📍 Madrid