Software Engineer, AI Agent

Sendbird is seeking a Senior Software Engineer, AI Agent to lead core initiatives across our AI Agent platform. This role is central to scaling Sendbird’s vision for proactive, intelligent agent-based customer engagement.

You’ll own complex projects end-to-end—from scoping and architecture to implementation and delivery. You’ll act as a technical mentor, push innovation in agent orchestration, and bring deep experience in both full-stack development and LLM-based systems. The ideal candidate combines technical fluency with a builder’s mindset, bringing AI-powered experiences to life for customers at scale.

What You'll Do

• Technical Leadership
  • Design and lead implementation of core agent features, from advanced RAG pipelines to multi-step tool use.
  • Establish best practices for prompt engineering, agent orchestration, and observability, and testing.
• Agent Platform Development
  • Drive architectural decisions for building a scalable and fault-tolerant AI agent platform. 
  • Focus on developing core AI/ML agent logic and orchestration, ensuring that the intelligence layer powering our agents is robust and extensible.
  • Build and optimize supporting systems and pipelines that improve agent capabilities and performance (evaluation, observability, classification, etc.).
  • Take ownership of the full development lifecycle, ensuring our systems are performant, reliable, and secure.
• Prompt Engineering & Experimentation
  • Lead the development and evaluation of prompt strategies for diverse customer use cases, including designing A/B testing and automated regression pipelines.
  • Optimize agent performance by improving retrieval logic, embedding models, and enhancing RAG pipelines.
  • Stay on the cutting edge of AI research and apply new techniques to improve our platform.
• Mentorship & Collaboration
  • Guide junior engineers and interns through code reviews and technical planning.
  • Work cross-functionally with PMs, designers, and sales engineers to translate customer needs into technical solutions.

Who You Are

• 6–10 years of software engineering experience, including full-stack and backend ownership.
• Deep expertise in Python and JavaScript/TypeScript, with a track record of building and scaling production systems.
• Strong system design and software architecture skills, with experience in distributed systems and cloud-native deployments (e.g. AWS, GCP).
• Hands-on experience with LLM APIs and agentic frameworks (e.g., LangChain, LangGraph, etc).
• Strong English proficiency, with the ability to read and write effectively.

Extra helpful if you have

• Prior work with real-time or conversational interfaces.
• Experience with vector databases, search technologies, or large-scale data processing.
• Contributions to open-source LLM or AI tooling ecosystems
• Native-level English fluency.

Our KR benefits include (but are not limited to):

• Silicon Valley's stock options that can be exercised after one year
• Free parking at our Seolleung Office or commute by taxi and we can support that!
• Group insurance support for self, spouse, and children
• Support for medical checkups
• 7 additional vacations on top of compulsory annual leave
• 12-week paid parental leave (both mom and dad)
• Learn a Language benefit - we will provide an monthly reimbursement towards language lessons 
• Be Your Best Self: an annual monetary offering  (prorated by start date) for expenses ranging from professional development classes and training, to personality assessments, gym memberships, books, fitness classes, mental health services, and massages.  We want you to thrive!