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 ((Use the "Apply for this Job" box below).) 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, Point
72 Ventures, General Catalyst, and In-Q-Tel.

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  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 Dev Sec Ops  teams, and the customers’ 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.

• 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 Dev Sec Ops  teammate, or a non‑technical customer stakeholder, and you proactively share information so the right…