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 Rocq), 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 our Blogs 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, with backing 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.

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