Staff Software Engineer (Remote) in Belfast

We are looking for an engineer to help build a new generation of provenance and build information into the Cloudsmith platform. If you are motivated by solving problems of performance at a massive scale and passionate about your craft, you will find an environment in which you can thrive at Cloudsmith.

About Cloudsmith: Cloudsmith is transforming how organizations handle software artifacts and secure their supply chains. As a cloud native, multi-tenant platform, we enable organizations to build software better, through best-in-class artifact management and software supply chain security. Our vision is to become the software supply chain itself, powering the future of software delivery.

We are the world's most potent artifact management platform, built by developers for developers. Our platform supports over 30 formats spanning languages, container formats, and operating systems, with enterprise-grade features, including vulnerability and security scanning, world-class policy management and enforcement, and web-scale to handle the Fortune 500. Organizations integrate Cloudsmith as critical infrastructure into their development, deployment, and distribution pipelines, trusting us to protect and accelerate, regardless of scale.

Backed by top-tier investors and on a trajectory toward IPO and beyond, we're building mission-critical infrastructure that powers software delivery for organizations worldwide. Now is an exciting time to join us as we revolutionize how organizations deliver and secure software and help write the next chapter of our rocketship growth story.

The Role: As a Staff Software Engineer on the Supply Chain Trust team, you will play a key role in building platform capability that gives enterprise customers complete, end-to-end traceability from source code to built artifact. Not just where an artifact came from, but how it was built, what went into it, and exactly how it was used across every pipeline and deployment downstream.

Cloudsmith already sits in the middle of how organisations store and distribute software artifacts. You will build the infrastructure that captures, stores, and surfaces build provenance and pipeline usage data — so that when a customer asks which of their services consumed a given artifact, and what build produced it, the answer is in Cloudsmith, complete and trustworthy.

Our Team: We are four teams responsible for building application capabilities and the underlying platform upon which Cloudsmith is founded.

Key Responsibilities:

• Build: Design, implement, and ship the provenance ingestion service — capable of accepting provenance and attestation payloads from CI/CD systems, public registries, signed bundles, and customer-uploaded artifacts across a wide range of formats (SLSA, in-toto, SBOM attestations, Sigstore bundles etc).
• Build the validation engine that verifies cryptographic integrity and evaluates attestation data against configurable customer trust policies — SLSA level requirements, allowed builder identities, key material, and more.
• Expose: Deliver clean, well-documented APIs that make provenance data useful to customers and to other parts of the platform — queryable, auditable, and reliable.
• Collaborate: Work closely with product, customer success, and the wider engineering team to understand how enterprise security teams consume provenance data and translate that into features they love.
• Quality: Prioritise correctness, security, and observability — this is critical infrastructure customers trust with their software supply chain decisions.
• Share your expertise across the team through code reviews, documentation, and open conversation — a rising tide lifts all boats.

Experience, Qualities & Skills: We realise that not everyone will have every experience and expertise in every possible thing.

• Cryptographic Foundations: Comfortable with signing and verification: key material, ECDSA/RSA, certificate chains, OIDC-based keyless signing flows, and transparency logs.
• Backend & Platform Engineering Experience: 5+ years of production backend engineering, with real ownership of at least one complex service end-to-end.
• Strong experience with Python for building backend services and data pipelines.
• Familiarity with AWS services (e.g. Data Ingestion: Data Modelling: Experience building and versioning APIs consumed by external enterprise customers or third-party integrators.
• Multi-Tenant Systems: You have built or operated multi-tenant SaaS platforms and understand what data isolation, access control, and audit logging actually require in practice.
• Iterative Delivery: You understand the importance of shipping early and often and are comfortable making real-world trade-offs between a perfect design and getting something valuable in front of customers.

A competitive compensation package, including equity, comprehensive health, dental, and vision insurance, generous annual leave, and flexible working policies to suit your lifestyle. Including a professional development budget for conferences and training.

With the opportunity to shape a fast-growing Series B startup (and beyond). Regular (monthly-ish) travel may be required for team meetings. Regular (quarterly-ish) travel may also be required for events and customers. In addition to generous annual leave (PTO), we offer health and well-being benefits along with flexible family-friendly working policies.

Personal Growth: You will have an enormous opportunity to learn new skills alongside your colleagues, and your continued professional development is essential to us because it's important to you. We will support you with budgets for equipment, training, books, conferences, travel, and certifications.

Facilities: Cloudsmith is headquartered in Belfast, Northern Ireland, with fully-equipped office space that's open 24x7. Regularly for activities like working sessions, team planning, meets and greets, and sometimes other group activities (like games!). Many Cloudsmithers work remotely, so we rely on our online collaboration tools; We do not discriminate on age, religion, sexual orientation, citizenship status, military service, or health conditions.

The Final Word: We're looking for someone who has a passion for their craft, a collaborative attitude, and a desire to build a product customers love. We are critical infrastructure built by developers for developers, and we are building the world's software supply chain platform and ecosystem. We want to hear from you if you are excited to build the edge networking layer that powers software delivery at a global scale—balancing thoughtful design with real-world constraints—to leave a lasting impact on the software industry from today until IPO and beyond.