Why Kimchi?

Kimchi is the AI platform inside CAST AI. We started by helping companies run LLMs on their own Kubernetes clusters - now we're building the execution layer where agents do real work.

Our Infrastructure today: multi-model inference (MiniMax, Kimi, GLM-5, Nemotron, DeepSeek) with intelligent routing, an OpenAI-compatible API, and deployment flexibility from our GPUs to your VPC. The inference layer is the foundation. What we're hiring for sits on top of it: coding agents, agent runtimes, orchestration systems, and the reliability engineering that makes them actually finish things.

Tech Stack: TypeScript, Go, Kubernetes, AWS/GCP/Azure, MCP, Prometheus/Grafana/Loki, GitLab CI, ArgoCD.

Why harness engineering matters here
OpenAI and Anthropic ship models. They also ship one harness each - the scaffolding that turns a raw model into something that can plan, execute, recover, and complete work. We ship a different kind of harness: one built for cost-conscious, long-horizon autonomy, running on inference infrastructure we control end-to-end.
A decent model with a great harness beats a great model with a bad harness. We've watched this play out. The gap between what today's models can do and what you see them doing is largely a harness gap - and that gap is where we operate.

What you'll build
The ratchet.
Every time our agent makes a mistake, we engineer a solution so it never makes that mistake again. That means hooks that enforce constraints the model "knows" but forgets: pre-commit lint checks, permission gates, context compaction before the window fills. Success is silent, failures are verbose.

Long-horizon execution.
Our harness is built around spec-driven autonomy: meta-prompting, fresh context per task, worktree-per-slice git strategy, automatic replanning, crash recovery, stuck detection. We're implementing Ralph loops - when the model tries to exit, we intercept and reinject the goal into a fresh context. The agent reads state from disk and continues. Multi-session, multi-day work, without context rot.

Planner/executor splits.
Planning with a reasoning model, executing with a fast one, evaluating with a third. Separating generation from evaluation beats self-verification because agents reliably skew positive when grading their own work.

The harness surface.
CLI, TUI, MCP integration, sandboxed execution, telemetry. Our AGENTS.md is short - every line traces to a specific thing that went wrong. TypeScript on the surface, Go where it matters.

Memory and context.
Moving agents off laptops, giving them state that survives across sessions, managing context so information lands where it's actionable. Compaction, tool-call offloading, progressive skill disclosure.

What makes this different (with receipts)
You've seen the pitch: "we route to the best model." Everyone says that. Here's what we actually have:

• GPU infrastructure we own. Not just an API reseller. From GPU placement across clouds to the inference endpoint your agent calls - we control the cost curve.
• A harness-first thesis. We treat agent failures as configuration problems, not model problems. When we moved from a stock harness to our own, completion rates on internal benchmarks improved by 40%+ on the same model.
• Agents.md that earns every line. No brainstormed rules - every constraint in our system prompt traces to a real failure we saw and fixed.

Requirements:

• You've used AI coding agents in anger. Not demos - real work. You have opinions about Claude Code, Codex, OpenCode, Cursor. You know what it feels like when an agent gets stuck and why.
• Strong TypeScript or Go in production. Comfort moving between them. Our surface is TypeScript; our core is Go.
• You think in harness terms. You read "the agent hallucinated" and your first instinct is to ask what context it was missing, what hook should have caught it, what constraint should exist.
• You drive features end-to-end. Design → build → ship → measure → iterate. We don't have layers that absorb ambiguity for you.

Responsibilities:

• Build and evolve the agent harness - ship hooks, permission gates, and context compaction. Every AGENTS.md constraint traces to a failure you personally diagnosed.
• Own long-horizon execution - multi-session task completion via spec-driven prompting, worktree-per-slice git, Ralph loop recovery, and stuck detection. Completion rate is your metric.
• Architect planner/executor/evaluator pipelines - planning with a reasoning model, execution with a fast one, evaluation with a third. No self-verification.
• Manage agent memory and context - state persistence across sessions, context compaction, tool-call offloading. Zero context rot on multi-day work.
• Own the harness surface - CLI, TUI, MCP integrations, sandboxed execution, telemetry. TypeScript on the surface, Go where it matters.

What success looks like (after 6 months):

• You've shipped at least one major harness feature end-to-end: designed it, built it, measured it, iterated.
• You've added constraints to our AGENTS.md based on failures you personally observed and diagnosed.
• You've improved a measurable reliability metric - completion rate, context efficiency, or cost per successful task.
• You've formed strong opinions about where our harness is load-bearing and where it's dead weight.

What’s in it for you?

• Competitive salary (€6,500 - €9,000 gross, depending on the level of experience).
• Enjoy a flexible, remote-first global environment.
• Collaborate with a global team of cloud experts and innovators, passionate about pushing the boundaries of Kubernetes technology
• Equity options.
• Get quick feedback with a fast-paced workflow. Most feature projects are completed in 1 to 4 weeks.
• Spend 10% of your work time on personal projects or self-improvement. 
• Learning budget for professional and personal development - including access to international conferences and courses that elevate your skills.
• Annual hackathon to spark new ideas and strengthen team bonds.
• Team-building budget and company events to connect with your colleagues.
• Equipment budget to ensure you have everything you need.
• Extra days off to help maintain a healthy work-life balance.

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, Slovenia, and Ukraine.

*As part of our standard hiring process, we would like to inform you that a background check may be conducted at the final stage of recruitment through our third-party provider, Checkr.
*Please note that Cast AI does not provide any form of visa sponsorship/work permit.

#LI-Remote

We are searching for a highly motivated and versatile Workday Administrator to join our HR Technology team. This pivotal role will be the primary technical expert for our Talent Optimisation, Learning modules and Peakon - Employee Voice, ensuring these critical systems run smoothly, are configured optimally, and deliver an exceptional employee experience. The specific blend of responsibilities is flexible and can be adapted based on the candidate's unique technical skills, demonstrated competencies, and previous experience. We encourage candidates with strong core Workday skills and a desire to grow in a specific area to apply. If you thrive on solving problems, improving processes, and empowering employees through intuitive HR technology, we want to hear from you!

What you'll be doing:

Role Overview: architect of the integrated employee growth lifecycle. This role is responsible for the technical design and maintenance of the Workday Talent Management and Peakon Employee Voice ensuring that performance evaluations, succession planning, and compliance training operate as a single, unified ecosystem.

• Talent Optimization & Performance Design
• Business Process (BP) Engineering: design and optimize the end-to-end Performance Review and Multi-Rater BPs. You build the conditional logic that routes evaluations through different approval chains based on org-level or geography.
• Succession & Calibration: build and maintain Succession Pools and Matrix Grids (9-Box). You facilitate the technical execution of Calibration sessions, ensuring data security and auditability of rating changes.
• Development Planning: configure Development Goals so that they link directly to Learning objects, allowing managers to assign specific courses as part of an employee's annual growth plan.
• Advanced Learning Management (LMS)
• Digital Content Strategy: manage the upload, versioning, and lifecycle of SCORM, AICC, and xAPI content. You ensure that the Learning catalog is organized via a strict hierarchy of Topics and Campaigns.
• Compliance Automation: create sophisticated Learning Assignment Rules (Requirement Groups). You build the logic that automatically enrolls employees in mandatory training based on "Hire Date," "Job Profile Change," or "Location."
• External Content Integration: Manage the Cloud Connect for Learning connectors for third-party providers (e.g., LinkedIn Learning), ensuring that external completions are correctly recorded on the Workday Worker Profile.
• Data Governance & Reporting
• Cross-Module Analytics: build custom reports and Discovery Boards that track the "Training ROI"—comparing learning completion rates against performance rating improvements.
• Security & Anonymity: manage Intersection Security Groups to ensure Talent ratings (high-sensitivity) and Learning transcripts (compliance-sensitivity) are only visible to authorized personnel.
• Audit & Health Checks: perform regular "Tenant Health Checks" to ensure no "broken" learning links exist and that talent pools are populated with active employees.
• Unified Talent Optimisation & Learning Architecture
• Skills Cloud Alignment: manage the Workday Skills Cloud as the common language between modules. You ensure that skills identified in a Performance Review (Talent) map directly to the Course Catalog (Learning).
• Career Hub Management: configure the Career Hub to show employees "Suggested Learning" based on their specific career interests and job profile requirements, without relying on AI-automated suggestions.
• Peakon Employee Voice
• Survey architecture: manage end-to-end survey design, including the strategic integration of Custom Questions and localized attributes to ensure insights are relevant without causing "survey fatigue."
• Platform mastery: act as the primary administrator for the Peakon dashboard, configuring complex permissions and navigating both manager and administrator views to ensure seamless data access.
• Benchmarking: maintain a pulse on organizational health by analyzing how company performance aligns with Gaming industry benchmarks provided within the Peakon ecosystem.
• Statistical integrity: apply statistical logic to all datasets—evaluating significance and participation thresholds—to ensure leadership decisions are based on robust, reliable data rather than outliers.
• Deep-Dive segmentation: utilize advanced segmentation skills to slice data by department, tenure, and location, pinpointing specific "pockets" of engagement or friction.
• Trend analysis: distinguish between cyclical fluctuations and systemic cultural shifts by identifying long-term patterns in "growth" and other key engagement drivers.
• Closing the feedback loop: design and oversee the internal communication process, ensuring survey results are transparently shared back with employees to build trust and ensure every voice feels heard.
• Actionable reporting: translate raw data into clear, narrative-driven reports that help stakeholders move from "viewing scores" to "taking action."
• System Support & Enhancement
• Provide functional support for user inquiries and issues related to these modules.
• Participate in the planning, testing, and deployment of Workday bi-annual releases, assessing impact on owned modules.
• Develop and maintain custom reports (RaaS) and calculated fields specific to Talent, Learning and Peakon.
• Maintain comprehensive documentation for configurations, processes, and integrations.

We're looking for someone with:

• 3+ years of hands-on experience as a Workday Administrator or Functional Lead.
• Proven expertise with Talent Optimisation, Learning Management, and Employee Voice - Peakon business process configuration.
• Proficiency in Workday Business Process configuration, security, and reporting (RaaS, Calculated Fields).
• Excellent analytical, problem-solving, and troubleshooting skills.
• Ability to translate business requirements into effective Workday Learning and Listening solutions.
• Strong communication and collaboration skills, with a focus on employee experience.
• Fluency in spoken and written English is required to support global documentation and communication with cross-functional teams.

Bonus points for:

• Workday Pro certification in Workday Learning, Talent Optimisation or Employee Voice Peakon.
• Experience with other Workday modules (Learning, Peakon, Talent Optimisation) and their interdependencies.
• Experience working in a global organization.

About Vumedi:

Vumedi is the largest video education platform for doctors worldwide, dedicated to advancing medical education through innovative video-based learning. Our mission is to empower healthcare professionals by providing them with access to the latest clinical knowledge and surgical techniques from experts around the globe. We curate a vast library of high-quality educational content, enabling users to enhance their skills, stay informed about industry trends, and improve patient outcomes. We are headquartered in Oakland, CA, and have additional offices in Minneapolis, MN, and Zagreb, Croatia.

We're hiring a Principal Software Engineer to lead the development of our digital platform and products at this critical stage of Vumedi’s growth. 

Why join Vumedi right now?

• Build technology that matters in a fast-scaling Silicon Valley digital healthcare company: Your work directly impacts how doctors across the world learn and make decisions that save lives.
• Grow as we grow: Be part of a company in an accelerated growth phase, where expanding teams, products, and markets create real opportunities for ownership, leadership, and career progression.
• Build with AI: Work on applied LLM systems - from intelligent search to AI-driven content agents - and shape how AI transforms medical knowledge delivery.
• Own your craft end-to-end: Take full responsibility for building systems that scale globally and power mission-critical workflows.
• Collaborate globally: Join a world-class team of passionate engineers on modern tech stack which will further drive your career development.
• Have real product impact: Influence the direction of product development by collaborating closely with product and leadership teams.

About the role:

We’re looking for a Principal Engineer / Product Architect to lead the next evolution of Vumedi’s product architecture and technical direction. This is a hands-on, high-impact role - shaping how millions of doctors discover, learn, and collaborate through intelligent, scalable systems.

You’ll be both architect and builder, working directly with the CTO and engineering leaders across our US and Croatia teams to bring ambitious ideas from prototype to production.

What you’ll do: 

• Architect the future of Vumedi’s platform - from scalable video systems to AI-powered content discovery and personalized learning experiences.
• Prototype and build AI workflows and agents powered by LLMs (Large Language Models) to transform how doctors interact with knowledge, surface insights, and discover content.
• Work closely with Product, Data, and AI teams to build, deploy, and monitor intelligent services (classification, search relevance, personalization, summarization).
• Define architectural standards across backend, frontend, and infrastructure layers - ensuring reliability, maintainability, and scalability.
• Partner with engineering leadership to drive system migrations and modernization (Python/Django backend, React frontend, AWS infrastructure).
• Mentor engineers across pods and raise the technical bar through design reviews, prototypes, and shared best practices.
• Lead technical exploration of new tools - from vector databases and RAG frameworks to real-time video personalization - to keep Vumedi on the edge of applied AI.

This role is ideal for someone who loves to zoom out on system architecture and zoom in on code - someone who can imagine what Vumedi’s platform looks like in five years, then open their editor and start building it.

Who you are:

• 9+ years of experience building and scaling software systems, ideally in consumer, data, or AI products.
• Proven success as a Principal Engineer, Staff Engineer, or Architect leading major system designs end-to-end.
• Expertise in designing distributed systems and cloud architectures on AWS (EC2, Lambda, S3, CloudFront, ECS, RDS, etc.).
• Experience with LLMs, AI agents, or AI-enabled workflows — building, integrating, or orchestrating intelligent systems.
• Strong understanding of data modeling, API design, caching, and asynchronous event-driven systems.
• Passion for hands-on prototyping and bridging product ideas with technical feasibility.
• Clear communicator who thrives in cross-functional settings and mentors others through influence, not authority.
• Nice to have: familiarity with Django or other modern Python web frameworks, as well as familiarity with React and modern JavaScript/TypeScript stacks.

You can expect:

The base salary range for this role is determined by a number of factors, including but not limited to skills and scope required, unique relevant experience, and job-related skills.

Cash salary is but one component of our compensation package. It’s inclusive of base salary, education budget, supplemental health insurance, free meals allowance, work from an alternative workplace allowance, occasional awards - Christmas bonus, and an annual bonus.

We also offer stock options as part of our compensation package, giving you the opportunity to share in the long-term success and growth of the company.

This is a hybrid role, working 3 days a week (Monday, Wednesday, and Friday) in our Zagreb office.