AI Phone - Senior Agent Runtime Engineer

About Bjak

We are reimagining the phone. AI phones need to be proactive, intuitive, intelligent and low cost. This is a mission critical for rest of the world to adopt intelligence.

There are over 5 billion people using everyday applications such as email, messaging, notes, tasks, and calendars, yet most are not AI-native. Our mission is to build proactive applications and devices that bring intelligence into daily conversations, coordination and workflows, with minimal prompting.

Responsibilities

• Building the actual execution infrastructure for AI agents.
• Implement agent runtime and orchestration components.
• Build tool-calling and execution interfaces.
• Support multi-step and long-running task execution.
• Manage task state, execution history and asynchronous workflows.
• Implement error handling, retries and recovery mechanisms.
• Integrate multiple model providers.
• Build observability and tracing for agent execution.
• Optimize latency, reliability and inference costs.
• Work with context and memory components to provide relevant information to agents.

Requirements

• Strong backend engineering experience.
• Experience with distributed systems and asynchronous workflows.
• Experience integrating LLMs into production applications.
• Strong API and service architecture knowledge.
• Experience with queues, state management and observability.
• Good understanding of tool calling and structured outputs.

Preferred

• Production agent framework or custom agent runtime experience.
• Experience with Temporal or similar workflow orchestration systems.
• Experience with model routing and inference optimization.
• Experience with AI evaluation and tracing.