Principal Backend Engineer

About the Company At Twenty, we're taking on one of the most critical challenges of our time: defending democracies in the digital age. We develop revolutionary technologies that operate at the intersection of the cyber and electromagnetic domains, where the speed of operations exceeds human sensing and complexity transcends conventional boundaries. Our team doesn't just solve problems – we deliver game-changing outcomes that directly impact national security. We're pragmatic optimists who understand that while our mission of protecting America and its allies is challenging, success is possible. Role Summary You will serve as the principal technical authority for Twenty’s backend systems—setting the technical vision, architecture, and standards for mission-critical products used in U.S. national security. You’ll lead major architectural initiatives across teams, building real-time systems that process cyber operation data at machine speed across cloud and on-premises environments. You’ll partner closely with product, security, SRE, and operators to translate complex operational needs into scalable, reliable platforms. This is a hands-on technical leadership role for someone who thrives on hard problems, high stakes, and raising the engineering bar. Who You Are • You’re energized by building technology that protects democracies and has real-world operational impact. • You set high technical standards and raise the quality of systems, decisions, and execution around you. • You think in architectures and trade-offs—latency, reliability, security, operability, and cost. • You lead through influence: clear direction, strong reasoning, and calm decision-making under pressure. • You’re comfortable in ambiguous, high-consequence environments with evolving requirements. • You mentor senior engineers with direct feedback, strong support, and a bias toward ownership. • You build trust across disciplines—engineering, security, operations, and government stakeholders. What You’ll Do • Define the technical vision and reference architecture for Twenty’s backend platforms across products. • Lead organization-wide architectural initiatives spanning multiple teams and critical systems. • Architect scalable, fault-tolerant distributed systems for real-time operational data processing. • Design and evolve graph-based data systems that power relationship mapping and AI-assisted analysis. • Establish patterns and standards for microservices, APIs, and event-driven communication at scale. • Drive measurable improvements in throughput, latency, reliability, and operability of core services. • Partner with SRE and security to build defense-in-depth systems for high-assurance environments. • Mentor senior engineers and technical leads; guide reviews and high-leverage technical decisions. • Engage directly with government customers and field teams to validate approaches and priorities. • Represent backend engineering externally through technical writing, talks, or community contributions. Must Have • You have 12+ years of professional software development experience, including Staff/Principal-level technical leadership. • You have mastery-level proficiency in Go (Golang) building large-scale production backend systems. • You have deep experience designing distributed systems (fault tolerance, consensus patterns, and resilience). • You have expert-level experience with graph databases (e.g., Neo4j, AWS Neptune) including schema and query optimization. • You have led major architectural initiatives that changed how multiple teams build and ship systems. • You have strong cloud-native experience (especially AWS) including networking and security fundamentals. • You have a security-first mindset: threat modeling, secure coding, and practical zero-trust principles. • You have a Bachelor’s degree in Computer Science/Engineering (or equivalent practical experience). Nice To Have • You have experience integrating production AI/ML systems with graph and streaming backends. • You’ve built event-driven platforms with NATS, Kafka, RabbitMQ, or similar messaging systems. • You’ve operated hybrid cloud and on-prem deployments in regulated or constrained environments. • You’re familiar with government compliance frameworks (e.g., NIST, DoD standards, FedRAMP). • You have domain exposure to cyber threat intelligence, persona analysis, wireless, or IoT security. • You’ve published research, shipped open-source, filed patents, or spoken at major technical conferences. Tech Environment (You Might Work With) • Go (Golang), microservices, and high-throughput API platforms • Neo4j, AWS Neptune, and graph query/performance tooling • AWS (networking, security, compute, managed data services) • Event-driven architectures (e.g., NATS) and real-time data processing pipelines • Kubernetes, containers, service mesh, and cloud-native observability • Infrastructure as Code (Terraform/CloudFormation) and GitOps practices Security / Work Environment This role requires eligibility to obtain and maintain a U.S. Government security clearance and may involve work in a controlled environment. You must be able to work on-site in Arlington, VA with occasional travel to Fort Meade, MD and other government facilities. If this role sounds like you, apply and share with us your interest. Some positions may require eligibility to obtain a U.S. Government security clearance. Any clearance requirement will be listed in the role description. Twenty is an equal opportunity employer. We consider all qualified applicants without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, veteran status, disability, or any other protected status. If you need a reasonable accommodation during the hiring process, let us know and we will work with you.