Software Engineer - Fullstack

SimSpace serves as an AI Proving Ground where organizations can confidently train, test, and outmaneuver adversaries in any environment. Trusted by allied governments, militaries, enterprises, and research institutions worldwide, SimSpace enables adaptive, AI-ready defenses that stay ahead of evolving threats. Founded in 2015 by experts from U.S. Cyber Command and MIT Lincoln Laboratory, the platform unifies training, testing, and validation in a realistic, live-fire simulation—helping teams evaluate security investments, optimize performance, and compress cyber readiness cycles from months to days.

Why join SimSpace? We are an organization that is focused on building our culture and mindfully enhancing our atmosphere every day which is why we have collaborated on an integral value system. Our governing philosophy of being Human Centered is deeply embedded within our value system. We apply this philosophy to every one of our internal team members, external clients, and their customers.

How Do We Work? We believe that people are at the center of everything we do. SimSpace fosters a culture of continuous learning, curiosity, and professional growth. That belief shows up in action: in-house training, internal and external learning platforms, cyber conferences, industry events, and dedicated time for skill development. Our people are empowered to shape their careers - and it shows. Year over year, SimSpace consistently outperforms industry benchmarks in internal mobility, promotions, and total rewards growth.

Who Thrives Here? We are a team of innovators, protectors, and problem-solvers. We believe diversity of thought and experience fuels better solutions, and we’re committed to building teams that reflect the communities we serve. Whether you’re remote or office-based, you’ll collaborate with talented colleagues across departments and time zones, united by the mission to create a safer digital world.

We invite you to apply today!

Feature Team | React, Kotlin/Spring Boot, Kubernetes | AI Development

SimSpace is looking for a Senior Full Stack Engineer to join a feature team building production functionality across our platform. This role is backend-leaning, approximately 70% backend and 30% frontend, with work spanning APIs, services, data models, integrations, and React-based user workflows.

We are looking for an engineer who can own features end to end, use AI coding agents as a primary implementation tool, and still apply strong senior engineering judgment to architecture, code quality, testing, security, and production reliability.

What You Will Do

• Own features from requirements through implementation, testing, release, and production support.

• Build backend services, APIs, business logic, data integrations, and persistence layers using Kotlin, Spring Boot, PostgreSQL, and related technologies.

• Build and evolve React and TypeScript interfaces that complete user workflows and expose backend capabilities clearly.

• Work with Kubernetes-based environments and contribute to services designed for reliable deployment and operation.

• Use AI coding agents as a core part of delivery: prepare context, guide implementation, run tests, diagnose failures, refine code, and validate results.

• Review, understand, and take responsibility for AI-generated code before it ships.

• Collaborate with product, design, engineering, and QA to clarify acceptance criteria and deliver useful functionality.

• Design for maintainability, observability, security, performance, and reliable operation.

• Write meaningful automated tests and use CI/CD checks to prevent regressions.

• Help teammates improve their practical AI development workflows and code review practices.

Required Qualifications

• Senior-level software engineering experience delivering and maintaining production applications.

• Strong backend engineering fundamentals, including API design, object-oriented design, data modeling, persistence, error handling, testing, Git, and CI/CD.

• Hands-on experience with Java, Kotlin, Spring Boot, or comparable backend technologies.

• Practical experience with React and TypeScript for building complete user workflows.

• Experience working with REST APIs, microservices, and production data stores such as PostgreSQL.

• Comfortable working in Kubernetes or containerized deployment environments.

• A repeatable personal workflow for using AI coding agents to turn requirements into working, tested features.

• Ability to explain your AI-assisted development process with real examples: how you provide context, guide implementation, verify behavior, debug failures, and decide what to accept or rewrite.

• Strong ownership mindset: you can debug generated code, make independent technical decisions, and remain accountable for what ships.

Nonnegotiable AI Requirement

This role expects most feature implementation to be carried out with AI coding agents under your direction. Autocomplete, occasional prompting, or using AI only for code review is not enough.

You should be able to demonstrate a mature AI development workflow that connects requirements, code generation, execution, testing, debugging, and correction. The goal is not to outsource judgment to AI; the goal is to use AI to increase delivery speed while maintaining senior-level code quality and production responsibility.

Highly Desirable

• Experience with Kubernetes-native services, distributed systems, orchestration, or control-plane style APIs.

• Familiarity with networking fundamentals: DNS, TCP/IP, HTTP/TLS, ports, routing, and connectivity troubleshooting.

• Working knowledge of VMware virtualization or virtualized lab environments.

• Experience with event-driven systems, asynchronous workflows, message queues, or long-running operations.

• Experience helping a team adopt AI coding agents effectively without sacrificing quality.

• Familiarity with cybersecurity, simulation environments, SaaS integrations, or infrastructure-he