AI Architect – Agentic Workflows & LLM Infrastructure

About the opportunity

We’re looking for a hands-on AI Architect to join as our second engineering hire, helping us grow our founding engineering team.

We’re building an agentic system that triages accounting documents arriving through multiple channels, including email, WhatsApp, SMS and a mobile app. It classifies invoices and receipts, extracts structured data, communicates with clients and routes uncertain cases to human reviewers.

Working alongside our first engineer and the founders, you’ll help shape the AI architecture and take ownership of key parts of the system—from long-running agent orchestration and open-weight model deployment to evaluation, observability, guardrails and production reliability. You’ll have significant influence over technical decisions, with implementation and delivery shared across the team.

What you'll do:

• Shape and develop the long-running agentic pipeline, taking ownership of key components including orchestration, state, model routing, retries and fallbacks

• Build an evaluation layer that lets us compare and replace models without losing visibility into quality

• Deploy, test and optimize both managed and open-weight models in production

• Design deterministic guards and validated boundaries around probabilistic AI components

• Make the pipeline fully observable across quality, hallucinations, latency, cost and failures

• Develop RAG and retrieval workflows using customer-specific knowledge and vector databases

• Extend the human-in-the-loop review flow and ensure feedback improves the system safely

• Collaborate closely with our first engineer on architecture, implementation and production reliability.

We're looking for someone who has:

• Production experience automating business workflows with AI, supported by measurable improvements.

• Deep experience with agent frameworks such asLangGraph, Google ADK or Claude Agent SDK.

• Experience building stateful, long-running agents involving tool use, agent loops and human intervention.

• Production model deployment throughBedrock, Azure AI Foundry, Vertex AI or a comparable platform.

• Hands-on experiencedeploying and evaluating open-weight models such as Llama.

• Strong experience withevaluators, LLM-as-judge, hallucination measurement and confidence calibration.

• Experience withAI observability, deterministic guardrails, RAG and vector databases.

• Experience buildingMCP servers or clients, rather than only consuming existing integrations.

• Familiarity with A2A and agent-interoperability patterns.

• Experience with vLLM, OpenRouter, Hugging Face, Langfuse, Arize Phoenix or pgvector.

• Advanced use or extension ofagent harnesses such as Pi, Kimchi or OpenCode.

• Experience with multimodal document processing, OCR or intelligent classification.

• Experience with accounting, ERP, GDPR or other sensitive and regulated workflows.

What you'll get:

• The opportunity to build a product from the ground up, by joining as our second engineering hire and helping shape the founding team.

• Hands-on collaboration with our first engineer and experienced founders

• Significant ownership of key technical areas and influence over engineering decisions

• The chance to build real-world AI applications that solve meaningful business problems

• A fast-moving environment with minimal bureaucracy

• Office based in Belgrade, working closely with the founding product team.

Why this role is different:

You’ll join at an early stage, with room to shape both the product and how we build it. Working alongside our first engineer and the founders, you’ll explore problems, develop prototypes and turn them into production systems for accounting firms.

This role combines substantial technical ownership with close collaboration in a small, growing engineering team. If you enjoy building products from scratch, experimenting with AI and taking responsibility for the systems you develop, we’d love to hear from you!