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

About this 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.

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…