Senior Software Engineer | Product Foundations

Cast AI

Montenegro

Remote

BRL 440,000 - 609,000

Full time

3 days ago

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Benefits offered by this job

Competitive salary

Remote-first environment

Equity options

Learning budget

Annual hackathon

Travel onboarding to Vilnius

Job summary

Cast AI is seeking a backend software engineer to design, build, and operate essential Go services that power trust and accounting features across cloud-native infrastructure. You will own features end-to-end, from design through production rollout, and collaborate with product and other engineers to solve complex, real-world problems in a high-scale environment.

The role emphasizes strong Go skills, Kubernetes expertise, and experience with authentication/authorization, billing, and data

Qualifications

Strong software engineering foundations and clean abstractions.
Production experience with Go is strongly preferred; other languages acceptable with solid systems programming.
Built or operated trust-critical systems (authentication/authorization, billing, or accounting-related data).
Solid understanding of API design, versioning, backward compatibility, auth, idempotency, and async patterns.
Strong debugging, optimization, and performance-tuning skills for high-load environments.
Hands-on Kubernetes experience with deployments, pods, and services.
Experience with AI coding agents and agentic development workflows.
Demonstrated end-to-end ownership of a complex project.

Responsibilities

Design, build, and operate backend services in Go used by multiple teams and customers.
Own features end-to-end from design through implementation, testing, and production rollout.
Debug complex production issues involving security, billing or trust-critical flows.
Collaborate with product and other engineering teams to solve non-textbook problems.
Contribute to product direction and backlog shaping for future work.

Skills

Software fundamentals

Go programming

Kubernetes

Authentication/Authorization

API design

Performance tuning

High-load systems

Debugging

AI coding agents

End-to-end ownership

English fluency

Startup mindset

On-call rotation

Tools

Kubernetes

AWS

GCP

Azure

Terraform

PostgreSQL

ClickHouse

Job 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 countries:

Bulgaria, Croatia, Estonia, Greece, Hungary, Latvia, Lithuania, Poland, Romania, Slovakia, Slovenia, Cyprus, Malta, Finland, Sweden, Ireland, Moldova, North Macedonia, Montenegro 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.

Requirements

Strong software engineering fundamentals: you design clean abstractions, write maintainable code, and can justify your architecture choices - not just make something work.

Production experience with Go is strongly preferred; candidates without Go should demonstrate strong systems programming skills in a comparable language.

You\'ve built or operated trust-critical systems at scale - authentication/authorization, billing, or financial/accounting-adjacent data, where being wrong has real consequences.

Good understanding of API design best practices - versioning, backward compatibility, auth, idempotency, async patterns, and similar.

Strong debugging, optimization, and performance-tuning skills – including query profiling, index design, and database performance tuning beyond ORM usage.

Experience operating and optimizing systems under high load - you know how to find and fix the bottleneck, not just add more resources.

Hands‑on experience with Kubernetes - you understand the core concepts (pods, services, deployments) and have deployed or debugged something on a cluster.

Experience with AI coding agents and agentic development workflows.

You\'ve personally driven a complex project end-to-end.

Strong English skills, both verbal and written.

Startup mindset: adaptable, proactive, and comfortable with ambiguity.

Participate in on‑call rotation for teams that require it.

Nice to haves

Multi-tenant identity system design - authentication, authorization, SSO.

Enterprise identity protocols - SAML, OIDC, and SCIM for enterprise account provisioning and sync.

Billing, audit-trail, notification, or feature-flag systems in production.

Experience with cloud provider pricing/billing APIs across AWS, GCP, or 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.

Responsibilities

Design, build, and operate backend services in Go that other teams and customers depend on being correct.

Own features end-to-end: from design through implementation, testing, and production rollout.

Debug complex production issues involving security-, money-, or trust-critical flows.

Collaborate with product and other engineering teams to solve problems that don\'t have textbook solutions.

Contribute to product direction and backlog - shape what gets built next, not just how it\'s built.

Tools we use daily

Programming Language: Go

Cloud & Orchestration: Kubernetes, AWS, GCP, Azure

Infrastructure as Code: Terraform

Databases & Storage: PostgreSQL, Cloud Object Storage, ClickHouse

Messaging & APIs: GCP Pub/Sub, gRPC for internal communication, REST for public APIs

Observability: Prometheus, Grafana, Loki, Tempo

CI/CD & GitOps: GitLab CI with ArgoCD

What\'s in it for you?

Competitive salary (€6,500 – €9,000 gross, depending on the level of experience) plus separate compensation for on‑call participation (passive coverage and active interventions)