Job Summary: We are seeking a Senior Backend Developer to lead the design and development of a multi-entity financial API, optimize critical systems, and mentor team members—with a strong emphasis on architecture, code quality, and automation. Key Highlights: 1. Technical leadership and mentoring of other developers. 2. Complex and high-impact projects in international fintech. 3. A technically oriented environment focused on excellence and automation. **About Us** We are a leading technology company specializing in international financial APIs, connecting with multiple banking institutions. We combine innovation, code quality, and AI-driven automation to build mission-critical, secure, and scalable financial solutions. Our team works with cutting-edge technologies and maintains a strong focus on automation, testing, and technical excellence. **What We’re Looking For** We seek a Senior Backend Developer with extensive experience in PHP and complex financial systems—capable of making architectural decisions and leading projects. We value deep technical expertise, strategic thinking, and passion for code quality and efficiency. **Responsibilities** * Understand and contribute to the design and development of our multi-entity financial API. * Define scalable, secure, and highly available backend architectures. * Integrate international banking APIs and develop robust connectors for new institutions. * Optimize systems in mission-critical environments. * Implement test automation, deployment automation, and AI-powered tools to improve productivity and quality. * Mentor junior and mid-level developers, promoting best practices in coding, documentation, and processes. * Participate in strategic decisions regarding infrastructure, development standards, and technology selection. * Ensure the robustness and reliability of systems handling sensitive financial data. **Essential Technical Requirements** * **Advanced PHP**: complex backend development and optimization of existing systems. * **MySQL**: design and optimization of critical databases and complex transactions. * **REST APIs**: advanced architecture, integration, and documentation. * **Authentication and security systems**: OAuth, JWT, RSA, 2FA. * **Experience with financial data**: understanding of investment products, debt instruments, multi-currency operations, and compliance requirements. * **Complex data formats**: JSON, XML, CSV, PDF. * **Version control**: professional-level Git usage, including complex workflows. * **Advanced testing**: PHPUnit, TDD, mocking, and deep debugging. **Desirable Requirements** * Fluent English and Spanish. * Experience in **AI and automation** applied to development and testing. * In-depth knowledge of financial products: accounts, cards, loans, portfolios. * Ability to work on-site in **Alcorcón (Madrid)**. **What We Especially Value** * **Technical leadership and mentoring** of other developers. * A mindset centered on **automation and efficiency**, without compromising quality. * Experience in **mission-critical financial projects**, where precision is paramount. * Ability to rapidly learn and apply new technologies. * Exceptional attention to detail and code quality. **What We Offer** * **Competitive salary up to €50,000 gross annually**, based on experience and level of responsibility. * On-site position in **Alcorcón (Madrid)**. * Continuous training in **emerging technologies and AI tools**. * **Complex and high-impact projects** in international fintech. * A highly skilled, technically oriented environment focused on **excellence and automation**. * Opportunities to take on responsibilities in **architecture, technical leadership, and mentoring**. Are you interested in joining a team that combines financial technology with AI and automation? Please send your CV detailing your experience with PHP, APIs, and projects demonstrating your organizational capabilities. Employment Type: Full-time, Permanent contract Salary: Up to €50,000.00 per year Benefits: * Optional remote work Experience: * PHP: 5 years (Required) * APIs: 4 years (Required) Language: * English (Required) Work Location: Hybrid remote work in 46011 València