---
title: 'Senior/Staff Engineer - Bombadil at Antithesis'
canonical: 'https://feeny.ai/job/senior-staff-engineer-bombadil-antithesis-london-bmzyebskt4dy'
type: 'job'
last_seen: '2026-09-13'
---

# Senior/Staff Engineer - Bombadil at Antithesis

- **Company:** Antithesis
- **Location:** London, United Kingdom
- **Employment:** full-time
- **Work type:** onsite
- **Posted:** 2026-03-18
- **Last confirmed live:** 2026-09-13
- **Apply:** https://jobs.ashbyhq.com/antithesis/88f9ee26-c86f-4625-9ac2-cb268678044a/application

**Skills:** Rust, Property-based testing, Fuzzing, Web technology, HTTP, HTML, Javascript, CSS, Chrome Devtools Protocol, Playwright, Cypress, Selenium, TLA+, LTL, Parsers, Type systems, Interpreters

> Build and maintain the Bombadil open-source project, focusing on autonomous testing, property-based fuzzing, and web technology integration. The role involves working with specification languages, Chromium automation, and frontend development to improve software reliability.

## Job description

## About Antithesis

We've been quietly reinventing how the world thinks about software reliability, and we're just getting started! At Antithesis, we start at the foundations – we run entire software systems inside a deterministic simulation and break them in every way imaginable. Every issue then comes with a perfect reproduction, so you can identify root causes fast instead of spending days trying to recreate what went wrong.

The rise of AI-generated code has made this work more urgent than ever. Agents can write code faster than any human, but speed doesn't matter much when the output is buggy, stuck in review, or slipping through undetected. The verification bottleneck is real, it's growing, and solving it is one of the most consequential problems in software right now. That's what you'd be working on.

We're well-funded and deeply technical, the kind of place where the hardest problems get the most attention and the best ideas win regardless of who has them. If you want to do work that actually moves the needle on how reliable software can be, keep reading.

## About the Role

We're looking for engineers in the Senior to Staff levels to build the future of autonomous testing. No matter your particular field of experience, if you've been ambitiously building complex software and think you could be a fit; drop us a note.

In this role you will be part of the team that maintains our open-source project Bombadil (https://github.com/antithesishq/bombadil). This includes working with the specification language and verifier, Chromium automation, advanced property-based testing, frontend development, and much more.

Must have for this role:

- Proficient in Rust development
- Experience with property-based testing or fuzzing
- Comfortable with web technology (browsers, HTTP, HTML, Javascript, CSS)

Experience that would be a plus:

- Chrome Devtools Protocol, Playwright, Cypress, or Selenium
- Formal specification languages (e.g. TLA+ or some LTL)
- Implementing parsers, type systems, and interpreters

## About Our Team

Our team spans CS degrees, philosophy, mathematics, and everything in between, or nothing formal at all. What everyone shares is a high bar for engineering quality. We work in-person because it's how we build trust and tackle hard problems together.

Location: This position is 5 days in the office in London, UK.

## About Antithesis

## Company Overview
- **One-liner**: Antithesis provides an autonomous software testing platform that uses deterministic simulation and state space exploration to exhaustively find and reproduce bugs in complex, distributed systems.
- **Entity Type**: Private (Series A)
- **Headquarters**: Vienna, Virginia, United States (with satellite offices in London, UK and San Francisco, California)
- **Founded**: 2018
- **Founders**: Will (CEO), Ben (CTO), and Dave (co-founder) – full last names not publicly disclosed

## Core Business
- **Primary industry/industries**: Software testing, autonomous reliability, developer tools, infrastructure software
- **Target customers**: B2B, Enterprise – companies building complex distributed systems (e.g., databases, cloud infrastructure, fintech, blockchain)
- **Mission or purpose statement**: “De‑risk agentic development of critical systems” by exposing bugs without human review, false positives, or risking production.

## Products & Services
- **Antithesis Platform**: A SaaS/on‑prem platform that runs a customer’s complete system in a fully deterministic, ephemeral simulation. It exhaustively analyzes behavior using fuzzing and state space exploration, automatically exposes bugs, provides a root cause and perfect reproduction, and arms developers (including AI agents) with high‑signal correctness feedback.

## Market Standing
- **Valuation/Market Cap**: Not disclosed
- **Key Metric**: Total Funding – $182 M (latest round: $105 M Series A announced December 3, 2025)
- **Notable Investors/Partners**: Amplify Partners, Spark Capital, Tamarack Global, Patrick Collison, Sholto Douglas, and 31+ other investors. Customers include Jane Street, MongoDB, Confluent, and Tigris Data.
- **Growth Signals**: Launched out of stealth in 2024; 19 open job openings as of mid‑2026; customers report 40 × faster change verification, 10 × faster time‑to‑release, and discovery of severe bugs missed by all other testing.

## Competitive Advantages
- **Deterministic replay** of every bug found – eliminates the “cannot reproduce” problem.
- **Exhaustive state space exploration** that catches unknown unknowns without false positives.
- **Runs the entire system** (not unit/integration tests) – simulates production‑like conditions.
- **Already trusted by elite engineering teams** (e.g., quantitative trading firm Jane Street, leading database companies) – a strong reference moat.

## Strategic Focus
- Accelerate product innovation and expand support for **agentic development** – help AI agents build bug‑free code by providing high‑signal correctness feedback.
- Broaden platform coverage across **databases, cloud infrastructure, fintech, blockchain**, and other critical system domains.
- Scale go‑to‑market and customer success teams to meet enterprise demand.

## Why Work Here
- **Culture**: “Collaborative, highly technical, and customer‑focused” – deep‑tech environment solving hard distributed‑systems problems.
- **Work policy**: In‑office daily (Vienna, London, or San Francisco) to facilitate tackling difficult challenges together.
- **Perks & engineering culture**: Well‑funded startup with a long‑term mindset; team includes veterans from FoundationDB, Apple, Google, and MongoDB; emphasis on autonomy, technical excellence, and fun.
- **Interview process**: Transparent and respectful – they publish a “No Ghost Policy” and welcome unsolicited applications from talented candidates.

## Sources
1. [antithesis.com – Careers](https://antithesis.com/company/careers/)
2. [antithesis.com – Homepage](https://antithesis.com/)
3. [antithesis.com – Leadership](https://antithesis.com/company/leadership/)
4. [cbinsights.com – Antithesis Company Profile](https://www.cbinsights.com/company/antithesis)
5. [theconsensus.dev – Antithesis Profile](https://theconsensus.dev/company/antithesis.html)

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