Software Engineer — Key Management & Secrets (Go / Kubernetes / Cryptography)

One of the largest retail companies in Europe is building its own sovereign cloud from the ground up — infrastructure designed so that the business's critical data and services live within the European Union, fully independent of the major US or Asian providers.

Within that platform there's a team that doesn't build customer-facing features, but something far more fundamental: the system that protects, encrypts, and manages every key and secret the rest of the platform depends on. Without this team, nothing else can be considered secure.

We're looking for the person who will join that team as a Software Engineer.

What you'll build

• The Key Management Service (KMS): the central system that generates, rotates, and protects encryption keys across the entire platform.
• Envelope Encryption flows (multi-layer encryption), managing the relationship between data keys and master keys.
• Kubernetes Operators that fully automate this system's lifecycle — with no manual intervention.
• APIs that other teams across the company will use to request keys, sign documents, or verify signatures, without needing to understand cryptography themselves.
• A product that must meet the industry's toughest security standards (AES, RSA, ECDSA, HMAC) and the audit requirements of a high-risk cloud environment.

You'll work under a "you build it, you run it" model: what you design, you operate. No launching it and walking away.

What we're looking for

• Real experience building software in Go, with Kubernetes as a core part of your day-to-day — not just deploying on it, but building Operators.
• Solid knowledge of applied cryptography: symmetric and asymmetric encryption, key management, digital signatures.
• Ideally, you come from a cybersecurity company, a cloud provider, or a platform/infrastructure team that already works with these concepts daily.
• You care about security not as a checkbox, but as the core of what you build.
• High level of English — the team works with international counterparts.

Why this project

• You'll build critical infrastructure with a high degree of technical autonomy: the team operates independently in order to sign off on security for the rest of the platform.
• You'll be part of one of the largest infrastructure projects currently being built in Europe, with strong team growth plans over the coming months.
• You'll work on real engineering problems, not business features — the kind of work few retail companies offer in-house.

Working model Hybrid: 2 days in the office (Barcelona) / 3 days remote.