Senior Backend Software Engineer

About The Company

Twenty Technologies is dedicated to making our adversaries think twice before attacking. Founded in 2024, Twenty industrializes offensive cyber operations for the U.S. and its allies. We are headquartered in Arlington, Virginia and have raised $138M from leading investors.

Role Summary

You will build the backend systems that power Twenty’s cyber and electromagnetic capabilities. Your work will ingest real-time operational signals, model complex relationships, and serve high-throughput APIs at machine speed. You will design and ship reliable services in Go, working with challenges like graph data modeling, event-driven architectures, and performance at scale. You will 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.

Who You Are

• Care about building systems that have real-world impact, especially in national security and defense of democracies.
• Excited by hard backend problems: throughput, latency, correctness, and operability under pressure.
• Take pride in clean interfaces—APIs that are intuitive, consistent, and built to evolve.
• Think in systems: data models, services, and workflows that work together reliably.
• Pragmatic and iterative—ship value quickly, then harden, measure, and improve.
• Collaborate well across disciplines, communicate clearly, and welcome direct feedback.
• Default to ownership: you notice gaps, propose solutions, and drive them to completion.

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.
• 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.

Must Have

• 5+ years of professional software development experience building backend (or full-stack) applications.
• Strong proficiency with Go (Golang) and have shipped production services with it.
• Experience working with graph databases (Neo4j, AWS Neptune, or similar), including schema design and query performance.
• Working knowledge of event-driven architectures and message queues/streaming systems.
• Experience building and maintaining APIs (REST and/or GraphQL).
• Experience with cloud infrastructure, ideally AWS, and understand cloud-native deployment patterns.
• Hands-on experience with containerization and microservices architectures.
• A strong foundation in secure coding practices and can reason about security tradeoffs.
• A bachelor’s degree in Computer Science, Software Engineering, or a related field, or equivalent practical experience.

Nice To Have

• Delivered software in defense, security, or other mission-critical environments.
• Built systems for analysts, operators, or high-tempo users where speed and reliability matter.
• Built AI/ML capabilities into production systems (inference, pipelines, or tooling).
• Experience with large-scale data processing and analytics workloads.
• Contributed meaningfully to open-source projects.
• Used observability tooling (metrics, tracing, logging) to debug and improve production systems.

Tech Environment (You Might Work With)

• Go (Golang)
• GraphQL/REST
• Graph databases (Neo4j, AWS Neptune) and complex graph schemas
• NATS and event-driven architectures
• AWS, microservices, containers
• CI/CD pipelines, automated testing frameworks, infrastructure-as-code patterns
• Monitoring and observability tools

Benefits

• Health. Medical, dental, and vision plan options.
• Life / AD&D, disability coverage options.
• Paid parental leave for eligible full-time employees.
• Vacation. Paid holidays and flexible PTO.
• Retirement. 401(k) with pre-tax and Roth options. HSA/FSA options, dependent care FSA.

Compensation Range

$159K - $263K