Senior Software Engineer, Formal Verification

Category Labs (formerly known as Monad Labs) is a team of systems engineers and researchers on a mission to design and build at the frontier of decentralized technology. We strive to deliver significant improvements over existing blockchain solutions. After raising $225M in series A funding, led by Paradigm, we are growing our team.

We’re the team behind Monad, a high-performance, EVM-compatible Layer 1 whose public mainnet is now live. We write the core software that runs it: a parallel-execution EVM, a custom state database, and a BFT consensus client, all developed in the open.

The Role

We’re hiring a Senior Software Engineer in Formal Verification to prove the correctness of the Monad implementation. Your work will involve writing machine-checked proofs about real production C++ code, including concurrent features like optimistic execution and novel Monad mechanisms such as reserve balance and optimized page-level storage. You’ll work in Rocq (formerly Coq), using the Iris separation logic framework and the BRiCk formal semantics of C++, building models of our designs and proving the implementation equivalent to them, as a vital member of a small, high-performing team.

What You’ll Do

• Formally verify the highest-risk parts of the Monad implementation, including concurrent and parallel execution logic.
• Build and refine Rocq models of system designs, then prove the C++ implementation equivalent to those models, catching design and implementation bugs before they reach main.
• Develop specifications and weakest-precondition proofs for production C++ using BRiCk and Iris separation logic.
• Strengthen theorem statements and proof automation, and devise approaches that scale verification to a fast-moving codebase.

Who You Are

• You have at least 5 years of software engineering experience in C++, much of it building performant systems from scratch – databases, device drivers, embedded systems, or the like.
• You have hands-on experience with an interactive theorem prover, ideally Rocq (formerly Coq), and can write machine-checked proofs about real, running code.
• You reason about concurrency and memory with a rigor most engineers never need – and you're drawn to problems where "probably correct" isn't good enough.
• You have sharp instincts for software architecture, memory management, and performance profiling.
• You hold a Bachelor's, Master's, or PhD in Computer Science, or have equivalent experience.
• You communicate clearly and thrive on a small team where everyone owns the result.

Why Work with Us

• Challenging problems: You’ll work on extremely challenging problems with massive impact. See ourBlogs and Publications & Talks for a flavor of the problems we are solving in the real world.
• Huge opportunity: The Ethereum Virtual Machine (EVM) standard is ubiquitous, but existing EVM-compatible chains are very slow. Monad’s core innovations offer developers the best of both worlds (portability and performance) and are a game-changer for mass user adoption in crypto.
• The right team: You’ll be part of a small, exceptional team (engineers and researchers make up 90% of the team).
• Open by default: Our core software is public on GitHub. You’ll build in the open, and your work ships where the whole ecosystem can see it.
• Culture: We’re a lean team working together to achieve very ambitious goals. We are united in our culture of collaboration, low ego, and high-quality output. As an early member of our team, you’ll help to shape our culture.
• Compensation: You’ll receive a competitive salary and equity package.
• Resources and growth: We’re well-capitalized, withbacking from leading venture funds like Paradigm, Electric Capital, Greenoaks, Dragonfly, and Coinbase Ventures. We keep a lean team, and this is a rare opportunity to join. You’ll learn a lot and grow as our company scales.

How We Use AI

We’re an AI-native team, and we expect engineers to use coding agents and keep up as the tooling evolves. A few things we believe:

• AI is leverage, not a crutch. Review what it generates with the same scrutiny you’d give a teammate’s PR, and own every line you ship.
• Judgment is what matters, not how long you typed by hand. We won’t ask for “N years of [tool].” The stack turns over every few months, so what matters is that you pick up new tools fast and know where and when they apply.

Salary and Benefits

The base salary range for this role is $180,000 – $250,000. This reflects the minimum and maximum range across US locations. It does not include benefits, token, or equity incentives. The final offer may vary based on factors such as relevant skills, experience, domain expertise, and work location. If you are based outside of the US, we have geographic considerations that may impact your final compensation.

Benefits for all Full-Time Employees:

• Private health insurance options
• Flexible paid time off
• Monthly wellness reimbursement
• Paid parental leave

Benefits for US employees:

• World-class benefits package with 100% paid medical, dental, and vision insurance including 75% coverage for dependents and HSA + FSA options
• 401(k) with company match
• Lunch and dinner stipend (in-office NYC)

Benefits for employees hired through an EOR (outside of the US) will be based on EOR offerings and country-specific requirements.

Category Labs is an Equal Employment Opportunity (EEO) employer and welcomes all qualified applicants. Applicants will receive fair and impartial consideration without regard to race, sex, color, religion, national origin, age, disability, veteran status, genetic data, or other legally protected status.