Senior Backend Software Engineer

About the role

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 (www.twenty.io http://www.twenty.io) 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 build the backend systems that power Twenty’s cyber and electromagnetic capabilities—software that ingests real-time operational signals, models complex relationships, and serves high-throughput APIs at machine speed. You’ll design and ship reliable services in Go, working with known-hard problems like graph data modeling, event-driven architectures, and performance at scale. You’ll partner closely with product, frontend, and domain experts to turn operator needs into durable platform capabilities. This role spans both cloud and on-premises environments supporting mission-critical U.S. national security outcomes.

WHAT YOU’LL DO

- Design and implement scalable backend services in Go that improve operator decision-making and response.

- Build high-performance APIs that power customer-facing workflows and internal platform capabilities.

- Model complex relationships in graph databases and optimize schemas and queries for speed and clarity.

- Implement event-driven systems (e.g., with NATS) to process real-time operational data streams.

- Develop and maintain automated tests to protect correctness, security, and performance as the system evolves.

- Build and operate microservices deployed on AWS, with an eye toward resilience and cost-aware scaling.

- Create and improve CI/CD pipelines that enable fast, secure delivery of new capabilities.

- Partner with cyber operations experts to translate domain needs into robust product features.

- Collaborate with frontend engineers on API contracts and data structures that are efficient and usable.

- Evaluate new technologies and patterns that could unlock better operational outcomes.

WHO YOU ARE

- You care about building systems that have real-world impact, especially in national security and defense of democracies.

- You’re excited by hard backend problems: throughput, latency, correctness, and operability under pressure.