Senior Software Engineer, Full-stack

CONSEQUENTIAL WORK. DEDICATED PEOPLE. ABOUT ONEBRIEF Onebrief builds collaboration and AI-powered workflow software for military planning and operational coordination. Today, many critical planning workflows still rely on fragmented systems, static documents, and disconnected tools that make collaboration and decision-making unnecessarily difficult. Onebrief brings modern software, AI, and real-time collaboration into those environments, helping teams operate with greater clarity, coordination, and adaptability in situations where decisions carry real-world consequences. We are a distributed team of builders from military, operational, and technology backgrounds who care deeply about improving how important work gets done. Some team members work remotely, while others work directly alongside customers in operational environments around the world. Founded in 2019, Onebrief is backed by leading investors including General Catalyst, Battery Ventures, Insight Partners, Sapphire Ventures, and Human Capital. Valued at more than $2 billion, we continue to invest in product innovation, AI capabilities, and team growth. ENGINEERING AT ONEBRIEF Engineering at Onebrief means building systems that must perform reliably in complex, high-stakes environments where operational outcomes matter more than activity, output, or elegant theory alone. This is work for engineers who care about reliability, adaptability, observability, and building systems that succeed under real-world conditions. As AI transforms how software is built, engineering here is increasingly focused on verification, judgment, and helping teams operate more effectively at scale. You’ll likely feel energized here if you care about: - meaningful technical challenges - systems that operate under real-world constraints - outcomes over activity - and grounded teams focused on solving important problems well. WHY THIS ROLE EXISTS Onebrief builds software for military planning, where the cost of a slow or wrong decision is measured in something more than a missed sprint. That raises the bar on the engineering itself. The systems have to hold up under real operational load, in environments where the customer can't tolerate failures or downtime. A Senior Software Engineer owns the hard parts of that. Not just shipping features, but taking the ambiguous, high-stakes pieces of a system and driving them to something that holds: designing for the failure cases, making the tradeoffs that keep the code maintainable as it grows, and lifting the quality bar for the squad along the way. This is the level where an engineer stops needing the problem handed to them fully framed and starts framing it themselves. Onebrief is building in the AI-native era, and Senior engineers here are expected to use these tools well: knowing what to trust to them, where human judgment stays non-negotiable, and how to keep quality and ownership intact as the leverage goes up. WHAT YOU'LL DO - Own end-to-end delivery of features and systems that directly impact customers, contributing across the full stack from frontend experiences to backend services and infrastructure. - Move between squads as business priorities evolve, applying your expertise to high-impact problems and quickly becoming effective in new domains. - Improve the scalability, reliability, and security of Onebrief's core platform by evolving shared systems, architecture, and engineering foundations. - Partner with engineers across the organization to shape technical decisions that balance long-term platform health with rapid customer delivery. - Help define how AI-assisted development is used at Onebrief, leveraging modern tooling to accelerate development while maintaining high standards for quality and maintainability. - Drive meaningful outcomes by solving the problems that matter most, making thoughtful tradeoffs that enable the team to move quickly without sacrificing engineering excellence.. WHAT WE LOOK FOR - 6+ years of software engineering…