Staff/Principal Backend Software Engineer

About the Company

America is under sustained cyber attack. Our adversaries infiltrate our networks, steal our IP, and degrade the digital infrastructure that modern life runs on. They’ve learned—correctly—that those attacks rarely produce consequences.

Twenty was founded to change that, by making our adversaries think twice before they attack us. Our vision is American and allied primacy in cyberspace—a future where they cannot contest us, deterrence is assured, and the free world remains secure.

Founded in 2024, Twenty Technologies ( industrializes offensive cyber operations for the U.S. and its allies. Headquartered in Arlington, Virginia, Twenty has raised $168M from Khosla Ventures, Accel, Caffeinated Capital, Friends & Family Capital, Point72 Ventures, General Catalyst, and In-Q-Tel.

Mission | On Site | Full Time | U.S. Citizenship Required / No Active Clearance Required

Role Summary

You’ll design and build backend systems that turn real-time operational data into mission-critical capabilities. This role owns core services that need to be fast, reliable, and secure—operating across cloud and on-prem environments. You’ll make high-leverage architecture decisions, drive technical execution, and raise the bar through mentorship and engineering standards. You’ll partner closely with product, operations, and frontend teams to ship systems that work under real-world constraints.

What You’ll Do

• Architect and build high-throughput backend services that process real-time operational data.

• Lead technical design reviews and choose pragmatic approaches for new features and system improvements.

• Design event-driven and distributed systems that are resilient, observable, and performance-tuned.

• Define stable APIs for internal and external consumers, partnering with frontend for seamless integration.

• Improve engineering excellence through code reviews, standards, testing strategy, and incident practices.

• Build and maintain CI/CD workflows that enable rapid, secure delivery.

• Troubleshoot complex production issues, lead incident response, and drive durable fixes.

• Partner with product and operational stakeholders to translate needs into deliverable technical plans.

• Contribute to technical strategy and roadmap planning across backend services.

• Support hiring by participating in interviews and helping define what “great” looks like.

Who You Are

• You’re motivated by high-stakes, real-world outcomes—especially in national security and cyber operations.

• You take ownership: you push projects from ambiguous problem to shipped, measured capability.

• You bring calm, high-judgment leadership during incidents, tradeoff discussions, and tight timelines.

• You hold a high bar for reliability, security, and maintainability—and you help others meet it.

• You communicate clearly with both technical and non-technical partners.

• You prefer simple, scalable designs and know when complexity is justified.

• You enjoy mentoring and leveling up engineers through feedback, pairing, and strong technical direction.

Must Have

• You have 10+ years building scalable backend systems in production environments.

• 4+ years of experience in Golang, or 4+ years writing server-side business logic in an object-oriented language (Java, Kotlin, C#, Python) or systems language (C, C++, Rust) with strong system design aptitude.

• You have led technical initiatives end-to-end, including architecture, execution, and delivery.

• You have experience designing distributed systems (e.g., event-driven architectures, messaging, consistency tradeoffs).

• You have built cloud-native services and operated them in production (AWS preferred).

• You have strong security fundamentals: secure coding, threat modeling, and defensible design choices.

• You have a track record mentoring engineers through code reviews, technical guidance, and feedback.

• You have strong communication skills and can align teams around clear technical decisions.

Nice to Have

• You have experience designing data models and queries in graph databases (e.g., Neo4j, AWS Neptune).

• You have used relational databases (ex: Postgres, MySQL, or MariaDB) to solve business problems and are able to reason about query performance.

• You’ve worked on defense, intelligence, or security-focused products with real operational users.

• You’ve shipped large-scale data processing systems (streaming, near-real-time analytics, or similar).

• You’ve integrated ML/AI capabilities into production systems in a practical, measurable way.

• You have open-source contributions or personal projects that demonstrate strong engineering craft.

Tech Environment (You Might Work With)

• Go (Golang) business logic

• AWS and hybrid cloud/on-prem deployments

• Event-driven messaging (e.g., NATS)

• Containers and orchestration (Docker, Kubernetes)

• GraphQL and service-to-service APIs

• Graph databases (Neo4j, AWS Neptune) and complex relationship data

Benefits
What's on the table:

• Health. Medical, dental, and vision plan options. Life / AD&D, disability coverage options.

• Family. Paid parental leave for eligible full-time employees. 12 weeks for birthing parents, 4 for non-birthing parents, 6 weeks for adoptive, foster, or intended parents through surrogacy.

• Vacation. Paid holidays and flexible PTO. Take what you need.

• Retirement. 401(k) with pre-tax and Roth options. HSA/FSA options, dependent care FSA.

Benefits vary by location, role, and eligibility. Full plan details provided during the interview and offer process.

Due to U.S. government contract and security requirements, this role is limited to U.S. citizens . Some positions may also require eligibility to obtain and maintain a U.S. Government security clearance. Any active 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, consistent with applicable law.

If you need a reasonable accommodation during the hiring process, let us know and we will work with you.