The Opportunity
Build the infrastructure for more capable AI agents.
Agents work faster, cheaper and more reliably when they write code instead of making one tool call at a time. That code needs somewhere safe to run. Monty is our answer: a Python interpreter written from scratch in Rust, with no filesystem, environment or network, that starts in under a millisecond and can be paused, dumped to bytes and resumed later. Monty is open source and reached 1.0 in September. Full Monty is the commercial product that runs the same sandbox behind a WebSocket, distributed as a container image.
We're looking for a senior Rust engineer to work directly with our founder, Samuel Colvin, on both. Roughly 60% of the work is on open source Monty and the rest on the commercial product. You'll take on hard problems in performance, security and reliability, and turn them into software customers depend on, with substantial ownership of technical decisions and what we release.
What You Will Do
- Expand what agent-written code can do inside Monty, including CPython compatibility.
- Maintain Monty's security. This means reviewing PRs and inventing ways to systematically challenge and check the sandbox.
- Improve performance, right down to the interpreter and potentially a JIT in future.
- Build and run the commercial product: production reliability, scaling, and the operational work of a service customers pay for.
- Maintain the wire protocol, the Python, TypeScript and WebAssembly bindings, and the docs.
- Help developers see what Monty makes possible: examples, docs, and answering users on GitHub and Slack.
Who You Are
We expect a candidate for this position to have:
- Deep experience with Rust and its ecosystem. If you don't have a rough idea of the difference between
BoxandArc, this probably isn't the right job for you. - Fluency directing coding agents as the primary way of producing software. Most of Monty's code is written by agents, and you stay responsible for its correctness, design and security.
- Comfort working on both open source and closed source software, and with the production reliability a paid product requires.
- An understanding that open source software needs explaining as well as building: you can show potential users why they should use it, and enjoy doing so.
- A habit of asking what a change lets sandboxed code do that it could not do before.
- Working knowledge of Python, enough to know or find out what CPython does.
- At least 5 years of software engineering experience.
Nice to haves but not required:
- An interest in generative AI and in how best to empower agents to complete tasks.
- Experience with interpreters, compilers, garbage collectors or language runtimes.
- Experience running untrusted code or a multi-tenant service at scale.
- Contributions to open source Rust projects.
- Knowledge of OpenTelemetry and Kubernetes.
Non-Technical Requirements
- Live and work in a timezone between PT (UTC-8) and CET (UTC+1)
- Able to travel to EU, UK and US up to 4 times a year to join our off-sites
- Willing to join our on-call rotation, roughly 1 week in every 10
About Us
Pydantic Validation is the data validation library that powers modern Python development - 500 million downloads per month, used by virtually every tech company you've heard of. Why? Because we obsess over developer experience and write code we'd actually want to use ourselves.
We're applying that same engineering mindset to Pydantic Logfire, our observability platform with first class support for AI engineering, built for today's development reality: AI workloads, multi-language environments, and cloud infrastructure that's designed to be straightforward to set up and maintain.
We build with technologies developers actually want to work with:
- OpenTelemetry for standardized instrumentation
- SQL for intuitive querying (no proprietary query language to learn)
- Rust, Python, and TypeScript for performance and productivity
- Postgres, DataFusion, and object storage for scalable backends
Unlike other companies that pay lip service to open source, we commit over 20% of our engineering team to maintaining and expanding our open source ecosystem. This includes the core Pydantic Validation library and Pydantic AI - our rapidly growing framework that's becoming the standard for AI application development. We're signatories of the open source pledge and build on open standards because we believe in interoperability, not lock-in. Use our OpenTelemetry-based SDK with any compatible backend - we're confident you'll choose us on merit.
We're backed by Sequoia Capital and run a fully remote team across multiple time zones, with regular in-person offsites.
Join our team of exceptional engineers who value substance over hype, practical approaches over perfectionism, and meaningful progress over busyness. We've built a culture that balances technical ambition with sustainable practices—minimal meetings and respect for your expertise and time. We're creating tools that genuinely improve developers' lives, and we're looking for thoughtful contributors who share our commitment to quality and our passion for elegant solutions.
Perks & Benefits
- 💰 Compensation: Competitive salary and stock options
- 🌍 Truly Remote: Work from anywhere within our timezone range - no office requirements
- 🌐 Global & Diverse: Join a multi-cultural team of 8+ nationalities
- 💪 Impact: Direct influence on tools used by millions of developers worldwide
- 🎯 Focus on Growth: Regular opportunities for learning and professional development
- 🤝 Team Gatherings: Connect with the team at our regular international off-sites
- 🏥 Healthcare: Comprehensive health coverage for you and your dependents
- 🎮 Flexible Hours: Work when you're most productive
- 💻 Equipment: Budget for your home office setup
- ⚖️ Work-Life Balance: flexible working hours and 33 days PTO no matter where you live (including public holidays, which you can choose to take or not)