Backend Software Engineer (Go & Kubernetes)

About our client At WeHunt we are partnering with the international technology hub of one of Europe's largest retail groups, which is building its own European sovereign cloud: a full cloud platform serving both the group and external customers who need full control over their data. We are looking for several Software Engineers to build core managed services of the platform, joining one of two teams: Key Management & Secrets Manager (the cloud's cryptographic security layer) or MailOut (a data-sovereign transactional email service built on KumoMTA). Location: Barcelona · hybrid Salary: 60-80k + yearly performance-based review Language: strong English required (German is a big plus) Description As a Software Engineer in Platform Services you will design, build and run cloud services used by external customers. Both teams share the same engineering DNA: scalable backend services in Go, Kubernetes Operators that automate the service lifecycle, customer-facing REST APIs and full ownership in production. The team you join depends on your background and interests. Key responsibilities - Backend Engineer — Build scalable, highly available backend services in Go. - Operator Developer — Develop Kubernetes Operators that automate the full service lifecycle, making it self-healing, scalable and easy to configure. - API Engineer — Build and maintain robust REST APIs that let customers manage the service programmatically. - Build & Run Owner — Own design, implementation and operations under a "You Build It, You Run It" model. - KMS & Secrets team — Develop key generation, rotation and lifecycle management, envelope encryption (DEKs/KEKs) and signing/verification workflows that meet industry standards (AES, RSA, ECDSA, HMAC) and sovereign-cloud audit requirements. - MailOut team — Develop a flexible, scalable transactional email service on KumoMTA, focused on availability and stability. Profile Searched (H/M/D) - At least 3–4 years of professional experience with Go and Kubernetes in production, well beyond basic usage. - Hands-on experience with Kubernetes Operators, CRDs or multi-tenant architectures. - Comfortable with Docker, ArgoCD, Helm or Terraform, and with testing, CI/CD and monitoring. - Real on-call experience and a track record of keeping systems stable. - Strong English. - For the KMS & Secrets team: knowledge of cryptographic algorithms (AES-GCM, RSA-OAEP, ECDSA) and key wrapping, or a strong drive to master them, plus an understanding of audit and compliance needs. - Nice to have: experience with HSM, PKI or secrets managers (KMS team), or with email platforms and MTAs (MailOut team). What we offer - Build core services of a European sovereign cloud from the inside. - Real end-to-end ownership in a team of 6–7 engineers. - Yearly salary review based on performance. - The stability and scale of one of Europe's largest retail groups. - An international environment with English as the working language.