Senior Software Engineer, Full-Stack - Security Platform

Vannevar is a defense technology company building AI to deter our adversaries. In the 21st century, conflict moves at algorithmic speed and foresight equals firepower. Our agentic AI is purpose-built to compete with China—from cross-Strait conflict to gray zone coercion. Trained on the most mission-relevant datasets in defense, our technology models adversary behavior, simulates campaigns, and recommends the best course of action to decision makers. Our AI systems are some of the most trusted in the industry and actively used on the front lines of the Indo-Pacific to keep the peace and save lives.

Exceptional technology starts with exceptional people. Vannevar is a small agile team combining world-class engineers with veteran strategists who bring deep expertise in defense and tradecraft. We’re building a company defined by mission impact, user empathy, and disciplined growth. In just three years, we grew from $3M to $80M in ARR, achieved early profitability, and reached unicorn status—proving that disruption doesn’t require an ego, and staying power doesn’t mean standing still.

At Vannevar, we’re building the next generation of mission software that powers decision-making across the national security, defense, and intelligence communities. Protecting the sensitive data and workflows behind those missions is foundational to our platform. The Security Platform team builds the authentication, authorization, and identity infrastructure that ensures the right people and services have access to the right resources—securely, reliably, and with minimal friction.

In this role, you’ll join a small, cross-functional team and own work across the stack—from frontend permission-management interfaces to backend services, authorization engines, and data models. You’ll partner closely with product engineers, designers, compliance and application security teams, forward deployed engineers, and mission users to build security capabilities that are intuitive, scalable, and deeply integrated into the product experience. This is a high-impact opportunity to shape how Vannevar approaches identity and permissions, build reusable platform capabilities, and enable new customer workflows across our products.

• Build and scale Vannevar’s centralized authentication and authorization platform, including tenant isolation across customer environments—from development through classified deployments.

• Own the internal self-service platform for user, group, and permission management; partner with Design to deliver intuitive administrative experiences for developers and mission teams.

• Build tooling and visualizations that help developers, administrators, and mission users understand and validate access permissions.

• Own and evolve Vannevar’s platform management interfaces, including the feature flag system, to support new products and customer needs.

• Partner with product engineering teams to build shared authorization and resource-sharing capabilities across the platform.

• Shape the long-term roadmap for the Security Platform team by driving scalable platform capabilities and improving the developer experience.

• 7+ years of software engineering experience, with a strong track record of designing, building, and operating scalable backend systems, and delivering full-stack features from conception through production.

• Strong backend expertise, including proficiency in one or more modern backend languages (e.g., Python, Java), experience with relational databases (e.g., PostgreSQL), distributed systems, and API design.

• Comfortable owning end-to-end development, including frontend work