Senior/Staff Forward Deployed Software Engineer - TS/SCI Cleared

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) 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.

Role Summary

You'll be on the ground at a government customer site, serving as a generalist engineering presence for Twenty's mission-critical platform in a restricted, air-gapped environment. Twenty builds software for cyber operations, and the applications you'll extend and operate are used by operators and analysts working against hard national security problems.

This is the broadest engineering role at Twenty. In a given month you might build a customer-specific feature, integrate a new data source, get an extension through the customer's deployment process, chase down a production failure, tune the monitoring that would have caught it sooner, and prototype an AI-backed capability with support from Arlington. You won't be an expert in all of it, and the role isn't designed to require that. For specialist work like data engineering and AI engineering, you'll deliver with guidance from the Arlington engineers who specialize in it. What the role does require is range: the ability to pick up an unfamiliar part of the system, get productive quickly, and produce work that holds up in production.

The office-based team can't access this environment, so you are the engineering presence where the software actually runs. Problems reach you first, and the judgment calls are yours: what's wrong, what's urgent, and what Arlington needs to know. When customer work is quiet, you'll build features for Twenty's core product applications, carrying what you learned in the field directly into the product.

You'll report directly to the VP of Engineering. You'll be part of a small forward deployed team, working closely with other on-site colleagues, the Arlington-based product engineering and DevSecOps teams, and the customer's own technical staff.

If you're a strong generalist who wants your work in the hands of operators the same day you build it, and you'd rather own a production system end to end than ship features into a backlog, this role is for you.

Who You Are

• You independently identify the right solution to ambiguous, open-ended problems. Problems reach you before they're fully defined, and the environment's constraints are discovered, not documented; you investigate, form a design, and deliver without waiting for a spec.

• You have real range. You've shipped across more of the stack than your title suggests, and you get productive in unfamiliar systems quickly. You'd rather be effective at many things than perfect at one.

• You know the difference between what you can do alone and what you should do with help, and you actively use Arlington specialists as a resource without being dependent on them for every decision.

• You respond with urgency to operational issues and own resolution within your sphere. You're unafraid to call an incident when the signal warrants it.

• You proactively create and update runbooks and documentation for the components you own. In an environment the rest of the team can't access, what you write down is what they know.

• You understand the customer and the mission well enough to know which work has the greatest impact, and you redirect your focus when what you're doing isn't moving the needle.

• You tailor your communication to your audience, whether that's a product engineer in Arlington, a DevSecOps teammate, or a non-technical customer stakeholder, and you proactively share information so the right people stay informed and aligned.

• You're comfortable operating in secure environments where tooling is limited, internet access is not a given, and the stakes are real.

What You'll Do

Customer-Specific Features & Extensions

• Design and build features, extensions, and integrations that adapt Twenty's applications to this customer's mission, workflows, and environment.

• Work directly with customer users and technical staff to understand what they actually need, then scope and deliver it, making pragmatic trade-offs between speed, robustness, and what the environment allows.

• Write code that is testable, debuggable, and maintainable by engineers who can't access the environment in which it runs. Tests carry unusual weight here: they're how Arlington trusts a change they'll never see run.

• Write code that meets the security standards of classified environments: no hardcoded secrets, disciplined credential handling, and audit-ready practices throughout, so your work moves through the customer's approval process without friction.

Data Integration & AI-Backed Capabilities

• Build software extensions that retrieve, parse, transform, and load new data sources into Twenty's applications, working with forward deployed data engineers where present and Arlington data engineers where not.

• Investigate unfamiliar source systems and data formats, working with customer stakeholders to understand semantics, access patterns, and constraints before writing code.

• Extend and field-test AI-backed capabilities in Twenty's applications with guidance from Arlington AI engineers, and report back what actually works against real data and real users.

Deployment & Site Reliability

• Work with the customer's deployment team to get software approved, deployed, and running in the high-side environment, and execute deployments and updates in coordination with Arlington engineering.

• Monitor the health of the platform and its data flows on-site using the LGTM stack (Grafana, Loki, Tempo, Mimir); identify anomalies and degradations before they become incidents. In an air-gapped environment, efficiency compounds.

• Diagnose and resolve production issues where they happen, escalating to Arlington with a clear picture of what you found, not just what triggered the alert.

• Drive root cause analysis and post-incident reviews in partnership with the Arlington engineering team, and turn findings into runbooks, fixes, or upstream design changes.

• Participate in on-call rotation using PagerDuty, with clear escalation paths to the engineering team. The environment is air-gapped, so off-hours incident response may require returning to the customer facility rather than remoting in.

Product Engineering

• When customer-driven work is quiet, build feature capabilities for Twenty's core product applications alongside the Arlington product engineering teams.

• Surface patterns from the field that should become platform capabilities, and advocate for them with the product engineering team. What you generalize from one customer makes every deployment after it faster.

Customer & Team Liaison

• Serve as a consistent engineering presence for the government customer: professional, reliable, and clear under pressure.

• Relay operational observations, capability gaps, and customer feedback to the Arlington team accurately and promptly.

• Work alongside other forward deployed engineers and analysts, sharing context and coverage across the on-site team.

Must Have

• 6+ years of professional software engineering experience, including substantial time owning services or applications running in production.

• Strong generalist programming ability in at least one of Go, Python, or TypeScript, writing code that remote teammates can review, extend, and trust.

• Experience building and shipping backend services or full-stack features end to end: design, implementation, testing, deployment, and operation.

• Experience debugging production systems: reading logs, tracing failures across components, and root-causing issues under time pressure.

• Working operational fluency: Linux command line, containerized environments (Docker, Docker Compose), and enough observability tooling skill to monitor and operate what you ship.

• Demonstrated range: you've delivered production work outside your core specialty, such as data pipelines, integrations, infrastructure, or ML-backed features, and you're comfortable doing so with support from specialists.

• Experience in a forward deployed, field engineering, or embedded customer-facing engineering role, including deploying and operating software in air-gapped, classified, or otherwise restricted environments, with demonstrated ability to work independently and sound judgment about when to decide and when to escalate.

• Ability to work on-site full-time at a government facility in Northern Virginia, with travel to Arlington, VA (typically 4 days per month).

Nice To Have

• Hands-on experience building ETL/ELT pipelines or data integrations (example technologies: Airflow, NiFi, AWS Glue, or equivalent custom pipeline development), and solid SQL and schema design skills.

• Experience building LLM-backed application features or operating AI/ML systems in production.

• Hands-on experience with observability tooling (Grafana, Datadog, Splunk, or similar).

• Experience with streaming and message queue technologies (example technologies: Kafka, NATS, Kinesis, RabbitMQ).

• Background in a military, intelligence, or defense contracting environment.

Tech Environment (You Might Work With)

• Cloud: AWS (EC2, ECS, RDS, CloudWatch) in closed enclave environments

• Containers: Docker, Docker Compose

• Observability: Grafana, Loki, Tempo, Mimir (LGTM stack)

• Alerting / on-call: PagerDuty

• Messaging: NATS

• Databases: PostgreSQL

• Data integration: Twenty's purpose-built data platform and integration layer (in active development)

• Languages in use across engineering: Go, TypeScript, Python

Security / Work Environment

This role requires an active TS/SCI security clearance with full-scope polygraph. Work is performed on-site at a government facility in Northern Virginia, with travel to Twenty's Arlington, VA office typically 4 days per month. Access to systems is restricted and tooling constraints apply.

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.

If this role sounds like you, apply and share with us your interest

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.