Software Development Engineer, Kiro Web

The future of software development is agentic. AWS is building Kiro a frontier AI-powered development environment that autonomously tackles development tasks maintains context across interactions and continuously learns from its work. Kiro is already transforming how developers build and maintain software and were just getting started.

Were looking for a Software Development Engineer to build the server-side systems that power Kiro Web a local web application that manages multiple AI agent sessions through the Agent Client Protocol (ACP). Youll own the backend that spawns orchestrates and communicates with kiro-cli processes handling JSON-RPC 2.0 messaging over stdin/stdout WebSocket fan-out to connected browsers and the REST APIs that enable multi-agent team coordination.

The challenges are systems-level and novel: managing a pool of AI agent child processes with independent lifecycles building a WebSocket gateway that multiplexes real-time notifications from dozens of concurrent sessions implementing tool approval interception and relay and designing the inter-agent communication layer that lets orchestrator agents delegate work to specialized agents via REST. Youll also build the distribution infrastructure that delivers Kiro to millions of developers multi-platform builds CDN-backed metadata services and update delivery mechanisms.

Your impact spans both the local development experience and global distribution. Every developer managing AI sessions through the Kiro Web UI depends on your server layer. Every developer downloading Kiro for the first time uses your distribution systems.

This is your chance to build the engine behind the agent that builds the future.

Key job responsibilities
- Build and maintain the Kiro Web server (Fastify/ 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 Kiros 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-clis 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 22 Fastify WebSockets JSON-RPC 2.0 pnpm monorepo. The team is between Seattle and Portland shipping weekly.

- 3 years of non-internship professional software development experience
- 2 years of non-internship design or architecture (design patterns reliability and scaling) of new and existing systems experience
- 1 years of software development engineer or related occupational experience
- 1 years of designing and developing large-scale multi-tiered multi-threaded embedded or distributed software applications tools systems and services using: C# C Java or Perl experience
- 1 years of Object Oriented Design experience
- Bachelors degree or foreign equivalent in Computer Science Engineering Mathematics or a related field
- Experience programming with at least one software programming language

- 3 years of full software development life cycle including coding standards code reviews source control management build processes testing and operations experience
- Bachelors degree in computer science or equivalent

Amazon is an equal opportunity employer and does not discriminate on the basis of protected veteran status disability or other legally protected status.

Our inclusive culture empowers Amazonians to deliver the best results for our customers. If you have a disability and need a workplace accommodation or adjustment during the application and hiring process including support for the interview or onboarding process please visit for more information. If the country/region youre applying in isnt listed please contact your Recruiting Partner.

The base salary range for this position is listed below. Your Amazon package will include sign-on payments and restricted stock units (RSUs). Final compensation will be determined based on factors including experience qualifications and location. Amazon also offers comprehensive benefits including health insurance (medical dental vision prescription Basic Life & AD&D insurance and option for Supplemental life plans EAP Mental Health Support Medical Advice Line Flexible Spending Accounts Adoption and Surrogacy Reimbursement coverage) 401(k) matching paid time off and parental leave. Learn more about our benefits at OR Portland - 143700.00 - 194400.00 USD annually