Senior Software Engineer, AI Platform & Inference API

Cast AI; Poland; On-site; PLN 200,000 - 360,000; Full time

Job summary

CAST AI's Kimchi team is hiring across multiple squads. As a Senior Software Engineer, you will own features end-to-end across the API Platform and Agent Platform, shipping within weeks and collaborating with product and other engineering teams.

You will design scalable datastores and services, improve observability and performance, and partner with users to fix pain points while staying security-conscious and cost-aware.

Qualifications

• Production experience with Go or TypeScript is preferred; strong systems programming skills in a comparable language accepted.
• Strong debugging, optimization, and performance-tuning skills including query profiling and index design.
• Heads-on cloud experience (AWS, GCP, Azure) and Kubernetes is a strong plus.
• Observability tooling (Prometheus, Grafana, OpenTelemetry), CI/CD and DevOps practices are valued.
• Startup mindset: adaptable, proactive, and comfortable with ambiguity.
• Strong English skills, both verbal and written.
• You've personally driven a complex project end-to-end.
• (Agent Platform) Experience in virtualization, networking, security, and Kubernetes internals is a strong plus.
• (Harness) Experience with harnesses and creating AI workflows is a strong plus.

Responsibilities

• Architect planner/executor/evaluator pipelines – planning with a reasoning model, execution with a fast one, evaluation with a third.
• Manage agent memory and context – state persistence across sessions, context compaction, tool-call offloading
• Own the harness surface - TUI, MCP integrations, telemetry.
• Work directly with users - including our own colleagues - to identify, understand and fix pain points

Skills

Strong English skills

Debugging

Performance tuning

System programming

Startup mindset

Tools

Go

TypeScript

AWS

GCP

Azure

Kubernetes

Prometheus

Grafana

OpenTelemetry

CI/CD

Job description

CAST AI's Kimchi team is hiring across multiple squads. As a Senior Software Engineer, you will own features end-to-end across the API Platform and Agent Platform, shipping within weeks and collaborating with product and other engineering teams.

You will design scalable datastores and services, improve observability and performance, and partner with users to fix pain points while staying security-conscious and cost-aware.