Senior Software Engineer | Product Foundations
Senior backend engineer on Cast AI's trust-and-accounting layer: building auth/SSO, billing, audit, real-time cloud pricing, and reporting services in Go, running on Kubernetes, PostgreSQL, ClickHouse, and GCP/AWS. Remote role open to candidates in selected EU countries plus Ukraine.
- Compensation
- €6.5K–€9K / mo
- Location
- Bulgaria; Croatia; Hungary; Lithuania; Poland; Slovakia; Slovenia
- Work setup
- Remote
- Seniority
- Senior
- Employment
- Not specified
- Experience
- Not specified
- Category
- Software engineering
- Posted
Skills
Must have
- Strong software engineering fundamentals: clean abstractions, maintainable code, justified architecture choices
- Built or operated trust-critical systems at scale (authentication/authorization, billing, financial/accounting-adjacent data)
- Good understanding of API design best practices (versioning, backward compatibility, auth, idempotency, async patterns)
- Strong debugging, optimization, and performance-tuning skills including query profiling, index design, and database tuning beyond ORM usage
- Experience operating and optimizing systems under high load
- Hands-on Kubernetes experience (pods, services, deployments; deployed or debugged on a cluster)
- Experience with AI coding agents and agentic development workflows
- Personally driven a complex project end-to-end
- Strong English skills, verbal and written
- Startup mindset: adaptable, proactive, comfortable with ambiguity
- Participate in on-call rotation for teams that require it
Nice to have
- Production experience with Go strongly preferred; otherwise strong systems programming skills in a comparable language
- Multi-tenant identity system design (authentication, authorization, SSO)
- Enterprise identity protocols: SAML, OIDC, SCIM for provisioning and sync
- Billing, audit-trail, notification, or feature-flag systems in production
- Experience with cloud provider pricing/billing APIs (AWS, GCP, Azure) or tracking Spot instance availability
- High-cardinality time-series ingestion and querying at scale
- Understanding of Kubernetes internals
- CI/CD and DevOps practices experience
- Observability tooling (Prometheus, Grafana, OpenTelemetry) in production
Full description
Why Cast AI?
Cast AI is an automation platform that operates cloud-native and AI infrastructure at scale. By embedding autonomous decision-making directly into Kubernetes and cloud environments, Cast AI continuously optimizes performance, reliability, and efficiency in production.
The old way doesn't work. As Kubernetes and AI environments grow, manual decisions don’t. Cast AI replaces tickets, alerts, and manual tuning with continuous automation that adapts infrastructure as conditions change. Efficiency and cost savings follow naturally from that automation.
Over 2,100 companies already rely on Cast AI, including Akamai, BMW, Cisco, FICO, HuggingFace, NielsenIQ, Swisscom, and TGS.
**Global team, diverse perspectives
**We're headquartered in Miami, but our impact is international. We take a global and intentional approach to diversity. Today, Cast AI operates across 34 countries spanning Europe, North America, Latin America, and APAC, bringing a wide range of perspectives into how we build and lead.
**Unicorn momentum
**In January 2026, we achieved unicorn status with a strategic investment from Pacific Alliance Ventures, the corporate venture arm of Shinsegae Group (a $50+ billion Korean conglomerate). Our valuation now exceeds $1 billion, and we're just getting started.
Join us as we build the future of autonomous infrastructure.
This is a location-specific opportunity. We are currently accepting applications from candidates residing in the following European countries: Bulgaria, Croatia, Estonia, Greece, Hungary, Latvia, Lithuania, Poland, Romania, Slovakia, Cyprus, Malta, Finland,Sweden, Ireland, Moldova, North Macedonia, Montenegro, Slovenia, and Ukraine.
What you'll be solving
Every dollar Cast AI saves a customer has to be provable, every action taken on their infrastructure has to be attributable to someone authorized to take it, and every price used to make that case has to be current across every cloud, region, and availability zone. This is the trust and accounting layer underneath the whole platform: get it wrong, and customers can't log in, can't trust the savings number, or get billed incorrectly - any one of which ends the relationship.
This posting covers multiple teams working on different pieces of the same trust-and-accounting problem: authentication, authorization, and SSO for every user and workload. Billing, audit trails, notifications, and feature flags that keep the platform transparent for every customer. Real-time cloud pricing tracking across every region and availability zone, including Spot availability and discounts. And reporting that turns high-volume time-series data into fast, accurate answers about what the automation actually saved.