Software Development Engineer, Kiro Web

The future of software development is autonomous. AWS is building Kiro —a frontier Developer Tool that independently tackles development tasks, maintains context across interactions, and continuously learns from its work. This isn't just another AI tool; it's a fundamental shift in how software gets built and maintained. We're looking for engineers who want to shape this transformation. You'll work alongside exceptional talent solving novel problems at the intersection of AI and software engineering. The challenges are unique: building systems that operate autonomously, solve novel problem in Analytics, Fraud detection, Governance and ensuring Kiro is able to meet enterprises where they are—all while meeting AWS's exacting standards for scale, reliability, and security. Your impact will be immediate and visible. You'll ship features that directly improve how developers work. Daily collaboration includes code reviews, mentorship in both directions, and rapid skill development. From day one, you'll have opportunities to lead—whether that's owning projects, defining technical direction, or shaping how the team operates. This is your chance to build the agent that builds the future. Key job responsibilities - Build and maintain the Kiro Web server (Fastify/Node.js/TypeScript) — session manager, ACP client adapter, WebSocket gateway, and REST API - Implement the process-per-session architecture: spawning kiro-cli ACP child processes, managing JSON-RPC 2.0 communication over stdin/stdout, and handling lifecycle events (crash recovery, session resume, stale PID handling) - Build the multi-agent team orchestration layer — team session lifecycle, inter-agent prompt routing with topology validation, parallel dispatch, and skill injection - Design and implement the WebSocket fan-out system that multiplexes notifications from multiple ACP processes onto browser clients, tagged by session/team/role - Build and operate Kiro's multi-platform distribution system — metadata services, platform detection, CDN configuration (CloudFront), custom channel authorization, and release automation - Implement tool approval interception: hold execution when agents request permissions, emit approval requests to the frontend, and relay user decisions back to the agent - Write comprehensive tests, build monitoring/alerting, and participate in on-call rotations - Contribute to API design, architecture reviews, and team technical direction About the team Kiro Web builds the web-based experiences and platform services for Kiro. Our server layer is the bridge between browser UIs and kiro-cli's Agent Client Protocol — we spawn and manage AI agent processes, multiplex their real-time output to the browser via WebSocket, and orchestrate multi-agent teams through REST APIs. We also own the distribution platform that delivers Kiro builds worldwide via CloudFront. Tech stack: TypeScript, Node.js 22, Fastify, WebSockets, JSON-RPC 2.0, pnpm monorepo. The team is between Seattle and Portland, shipping weekly.