Software Engineer

The company Crooter is a London-based software company building the operating system for modern recruitment consultancies. We work with executive search firms, contingency agencies and embedded talent partners who want a single, intelligent workspace for the way recruitment actually works and we are hiring for one our client AfterQuery. About AfterQuery AfterQuery builds the most complex infrastructure powering frontier data creation for agentic and hard reasoning workflows. Working with the leading AI labs and the go-to data infrastructure partner for YC companies. Sharp hockey-stick growth. $34M raised. YC-backed. Founding team from Citadel Securities, Goldman Sachs, Morgan Stanley, Silver Lake. 40 employees. Founded 2024. FiDi, San Francisco. What You’ll Do End-to-end ownership over projects that push the frontier of AI evaluation. This is not a narrow role — one week you might prototype a new RL environment, the next you’ll deploy distributed experiments on Kubernetes. Design and build scalable systems — RL environments, APIs, and human-in-the-loop platforms. Collaborate across teams — research, product, and design to ship features quickly. Write clean, maintainable code — and contribute to documentation. Code reviews and design discussions — maintain the team’s technical bar. Solve scalability challenges — real-world reliability at scale. Core infrastructure — powering data and evaluation for leading AI labs. Experience 1–4 years as a full-stack SWE Experience at a high-growth startup, trading firm, or as a founding engineer End-to-end builder with ownership bias Technical Skills Full-stack: Next.js/React, Node.js/Python, Kubernetes Kafka, Redis, Elasticsearch Degree from a top school Profile Comfortable being client-facing with AI lab researchers On-site 5 days in San Francisco What Makes You Stand Out 0→1 engineering at a high-growth startup — built and shipped production systems end-to-end Experience at a human data AI company or working directly with frontier AI labs Integrated full-stack + distributed systems depth (not isolated frontend or backend only) Stable tenure with high-impact delivery in fast-paced environments Excited to build the data infrastructure that powers how the world’s best AI models learn Pay: $180,000.00 - $220,000.00 per year Benefits: Visa sponsorship Work Location: In person