Senior Principal Engineer, Agent Harness (AI)

TL;DR

Senior Principal Engineer, Agent Harness (AI): Leading the architecture and implementation of backend and platform services for AI-powered and agentic systems with an accent on agentic harness tooling and LLM orchestration. Focus on designing scalable, high-availability architectures, implementing RAG and memory systems, and driving DevOps excellence for production-grade AI workloads.

Location: Hybrid Sofia, Bulgaria

Company

hirify.global is a Nasdaq-listed software provider that enables customers to develop, deploy, and manage responsible AI-powered applications.

What you will do

• Lead the architecture, design, and implementation of backend and platform services for AI-powered and agentic systems.
• Design and build agentic harness tooling for developing, evaluating, debugging, and operating LLM-powered agents.
• Build reusable AI platform capabilities, including Agentic Memory, observability, and evaluation pipelines.
• Own complex technical initiatives end-to-end, from initial discovery and architecture to production rollout.
• Drive DevOps excellence through infrastructure automation, CI/CD, and cost-aware cloud architecture.
• Provide technical leadership by mentoring engineers and guiding high-level architectural decisions.

Requirements

• Extensive experience building and operating distributed backend systems in production.
• Strong hands-on experience with .NET services.
• Practical knowledge of Go, Python, and TypeScript.
• Expertise in containerization and orchestration using Docker and Kubernetes.
• Strong experience with cloud architecture, preferably AWS (storage, networking, security).
• Must be based in or able to work in Sofia, Bulgaria (Hybrid).

Nice to have

• Experience building AI platform infrastructure, agent frameworks, or LLM-powered applications.
• Knowledge of RAG, MCP, memory patterns, and agent lifecycle management.
• Experience with LLM observability, tracing, and OpenTelemetry.
• Familiarity with analytical databases like ClickHouse and tools such as LangChain or LlamaIndex.

Culture & Benefits

• 30 days paid annual vacation plus additional days off for your birthday and volunteering.
• Premium healthcare and dental care coverage and additional pension insurance.
• Employee Stock Purchase Plan Enrollment.
• On-site gym with CrossFit equipment and a climbing wall.
• Flexible working hours and the opportunity to work from home.
• Free underground parking with designated spaces for bikes and scooters.