Senior Software Engineer - Frontend

• 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).
• React (or any other component-oriented JS framework) - Required
• TypeScript - Required

• C#.NET - Preferred
• RDBMS / SQL - Preferred
• Amazon Web Services - Preferred

• Fluency in English is required for this role.

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.

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.
• 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).

This role is based in Madrid.

Win as One. Delight Customers. Deliver Great Outcomes.

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.