Harper
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B2B AI

Backend Engineer, AI Agents

Full-timeMid-Senior (3+ years)🇰🇷 Seoul

Build the backend that lets AI agents act inside large enterprises: APIs, data flows, and integrations with the systems they already run, kept reliable in production.

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About The Job

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Job Title

Backend Engineer, AI Agents

Salary

Industry-leading cash compensation plus a founding-member equity package

Location

Seoul, South Korea, on-site.

Company Description

The client is an enterprise AI company founded in 2025. In September 2026 it raised a $550M Series C led by Insight Partners, with Salesforce joining as a new investor, at a $5B valuation. Total funding is over $800M, and the company has grown to more than 35 markets and about 650 people.

Its product started as customer-facing AI agents and has grown into an open, model-agnostic AI operating system that connects agents, workflows, AI-native applications, enterprise context, integrations, and governance. Local teams automate real operations end to end with enterprise customers, take the first use case to production, and hand the capability over so the customer can keep expanding on its own. The Korea team is early.

What You'll Do

An AI agent is only as good as the backend behind it. You design and build the systems that let agents read from and act on an enterprise's data and tools, and you keep them reliable in production. You work directly with the customer, so you decide what gets built, not only how.

  • Design the backend and data flows behind each customer's AI agents.
  • Build APIs and integrations with the systems the customer already runs: CRM, ERP, contact center, and messaging.
  • Connect LLMs, the customer's internal data, and external APIs into a system that runs real work.
  • Own reliability, latency, and performance in the customer's live environment.
  • Work with the customer to define the problem and the KPIs that matter: response rate, conversion, handling time.
  • Move fast from prototype to production, and keep improving after launch.

Required Qualifications

  • 3+ years of hands-on software engineering, with backend or systems work in Python or TypeScript.
  • Solid understanding of REST APIs, databases, and cloud environments.
  • Working knowledge of LLMs, AI agents, or automation systems.
  • You have built prototypes fast under uncertainty and kept improving them.
  • Native or advanced business Korean for Korean enterprise customers, and English for working with the global team.
  • No Forward Deployed title needed. The bar is being an excellent software engineer.

Nice to Have

  • You have made your company's product work well for other businesses (B2B).
  • Complex system integration: CRM, ERP, or data pipelines.
  • LLM services in production: prompting, tool use, RAG.
  • Frontend or full-stack execution, not only backend.
  • Fast execution at a startup or on an early product.

Why Join

  • You are measured on real business impact, not model scores.
  • You own the whole path: problem definition, design, build, and operation.
  • You work with the global engineering team directly, in English, in real time.
  • The Korea team is early. What you build in the first year sets the direction here.