Founding Security EngineerFounding Security Engineer

About the role

Flashnet moves assets across otherwise separate financial systems. Our infrastructure powers billions of dollars in annualized volume, and the security of the systems we build is fundamental to everything we do.

We're looking for an exceptional security engineer to own that responsibility.

You'll work directly with our engineering team to understand how every part of Flashnet works, identify where things can go wrong, and design and implement systems that make those failures difficult or impossible.

Your work will span our entire stack, from transaction signing, key management, and cryptographic protocols to application security, infrastructure, and the integrations connecting Flashnet to external networks.

The problems are specific to moving value between systems that don't trust each other: making sure every transaction does exactly what was quoted, keeping signing keys safe at scale, reasoning about the trust assumptions of each network we connect to, proving settlement is correct, and holding up against counterparties who are actively looking for an edge.

You'll review architecture, audit code, identify attack surfaces, develop security tooling, and help build the internal practices that allow us to move quickly without compromising safety. You'll have the authority to challenge technical decisions and the responsibility to help engineer better alternatives.

This isn't a role where you hand engineers a list of vulnerabilities and move on. You'll be expected to get into the code, build fixes, and take ownership of security from design through production.

We're a small team operating critical financial infrastructure. You'll have significant autonomy and a direct hand in shaping how we build, secure, and operate Flashnet.

Requirements

• Deep experience securing production software, ideally in financial infrastructure, crypto, distributed systems, or other environments where security failures have real consequences.
• Strong software engineering skills. You can read, review, and write production code, ideally in Rust or another systems language.
• A solid understanding of applied cryptography, authentication, key management, and secure protocol design.
• Experience identifying and exploiting vulnerabilities, conducting security reviews, and reasoning about complex systems from an attacker's perspective.
• Familiarity with cloud infrastructure, networking, access controls, and securing distributed production environments.
• You're comfortable working across the stack, from low-level protocol implementations to application and infrastructure security.
• Exceptional judgment and ownership. You know when something is safe to ship, when it isn't, and how to solve the underlying problem rather than adding unnecessary process.

Experience securing exchanges, wallets, blockchain protocols, or trusted execution environments is a strong plus.

Apply

Email jobs@flashnet.xyz with your GitHub, LinkedIn, or personal website and a short note about your background. We'd especially love to hear about interesting vulnerabilities you've discovered, systems you've secured, or security research you've published.