Senior PHP Developer - Integrations & APIs (m/w/d)

We are looking for a Senior PHP Developer to take a key role in designing, developing and owning our system interfaces to external systems. You will work on a business-critical product used by thousands of hotels every day and play a central role in connecting our platform with external systems and partners. This role focuses on hands-on backend and interface development , API design and technical ownership of integrations in a fast-growing startup environment. You will act as the primary technical owner for interfaces and a key sparring partner within the engineering team and across departments. Aufgaben Your responsibilities Design, develop, maintain and document internal and external APIs and integrations using PHP and Symfony Take technical ownership of our interfaces and ensure their reliability, scalability and maintainability Integrate, monitor and maintain external systems and third-party APIs (e.g. PMS, booking systems, payment providers, partners) Define and improve interface architecture, standards and best practices Ensure high software quality through testing, code reviews, maintenance and clean documentation Support troubleshooting, error analysis and continuous improvement of integrations Collaborate closely with Product, QA, Partner Management and other Engineering teams Qualifikation What you bring Several years of professional experience as PHP Developer, ideally with a focus on integrations or APIs Strong expertise in PHP and relational databases (MySQL) Solid experience in designing and working with REST APIs, web services or similar interfaces Experience with GIT, Docker and CI/CD Ability to turn ideas into reliable, scalable and maintainable code Structured, quality-focused and pragmatic working style Required Fluent German (spoken and written) – this is a must Professional working proficiency in English Nice to have Experience with Symfony Familiarity with A/B testing and data-driven product development SaaS or startup experience Understanding of modern software architectures