Backend Engineer – API Integrationen, Connectoren, Worker/Jobs, Mailer Service, QA

This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Backend Engineer – API Integrationen, Connectoren, Worker/Jobs, Mailer Service, QA based in Spain. This role is an opportunity to build robust backend systems and integrations that connect critical business platforms and services. You’ll work across APIs, connectors, background jobs, messaging, email delivery, persistence, and quality assurance. The position requires an engineering mindset focused on reliability, traceability, and handling real-world failure scenarios rather than relying on happy-path implementations. You’ll design integrations that remain resilient through rate limits, webhooks, timeouts, retries, and other operational challenges. Working on a project basis, you’ll have significant ownership over technical deliverables and architecture decisions. This is a strong fit for a backend engineer who enjoys solving complex integration problems and building dependable production systems.