Loaded

Harness Engineer

Imagine a world where a customer can walk into any shop or browse any online store and pay in installments with just a few clicks - no bank queues, no physical paperwork, and no credit card hurdles. That is the reality Leanpay has been building for ten years!

We are at the forefront of the Buy Now Pay Later (BNPL) trend, with a team of professionals in retail, banking and software development who are passionate about changing the old-fashioned way of buying in installments.

With our 2024 €10M Series B funding milestone, we are scaling our Romanian operations and solidifying our market leadership in Slovenia. We aren’t just offering a financial product; we are offering retailers a way to grow and customers a way to shop with total digital freedom.

Based in Serbia, our IT team is growing month by month, yet actively preserves the benefits of working in a smaller group - flexibility, informality, openness, and knowledge sharing. Over the next few years, we plan to build the next generation of our lending platform: a cloud-native core around a modern core-banking ledger, an event-driven backbone, and clear domain boundaries, all while our current platform keeps serving customers.

Currently, we are expanding our AI team and looking for a Harness Engineer who will make AI agents a reliable part of building this platform, from requirements to production.

If you are a software engineer who likes to design and build software that makes AI agents reliable in real production work, and you like what you have read so far, check out the job description below:

What will the Harness Engineer be doing?

  • Designing and developing the software behind our AI delivery process - its stages, checks, integrations and workflow logic;
  • Building guardrails, recovery loops and observability for AI agents, so that a failure is visible, contained and cheap;
  • Turning architecture, security and regulatory rules into automatic checks, so that they cannot be skipped under pressure;
  • Diagnosing agent failure modes and fixing their cause in the process, not only the symptom;
  • Building and maintaining the mechanics that deliver knowledge to AI agents;
  • Delivering a small share of product features, to test the process on real work;
  • Supporting delivery teams in adopting the AI delivery process, proposing technical standards and sharing knowledge with colleagues.

What will the successful candidate have?

  • University degree with a technical orientation;
  • 4+ years of software development, with hands-on experience in building production software, system design and the full software development lifecycle (SDLC);
  • Hands-on experience with AI agents and AI-assisted development;
  • Knowledge of guardrails, recovery and observability for automated systems;
  • Strong problem-solving skills and clear written communication - in English;
  • We consider as a plus: experience in fintech or banking, and experience in designing systems that other engineers build on.

Experience in:

  • Software development in Java, Python, TypeScript or a similar language;
  • Software design, testing and code review practices;
  • CI/CD pipelines and build tooling (Jenkins, Maven or Gradle);
  • Docker, Kubernetes and Cloud Computing Environment (Google Cloud or AWS), including logging and monitoring;
  • AI coding agents (e.g. Claude Code) and their extension points - tools, hooks, MCP;
  • We consider as a plus: AI agent orchestration frameworks.

What are the compensation and benefits?

Leanpay cultivates a flexible work environment as well as a dynamic and agile operating model that will give anyone a high level of responsibility and exposure to the company's core business. Any successful candidate will have the chance to work with a talented and bold team, which will contribute to their personal and professional growth.

What we offer:

  • A competitive package aligned with similar positions on the market;
  • Opportunities for job advancement and career development;
  • 25 days of annual vacation;
  • Hybrid working model, based in our Belgrade office;
  • Lunch in the office;
  • Private medical insurance;
  • Annual 5 days of 100% paid sick leave;
  • Positive and flexible work environment.

If you feel this job fits you perfectly, we suggest you apply.

Shortlisted candidates will be contacted.

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