Backend Software Engineer – Data Infrastructure & AI

🚨 Software Engineer – Backend, Data Infrastructure & AI 📍 San Francisco – On-site I’m working with one of the fastest-growing companies in AI, building the expert reasoning and data infrastructure used to develop frontier models. They capture the step-by-step reasoning, trade-offs and judgment of nearly 100,000 verified domain experts, transforming it into high-quality training data, evaluation frameworks and agent environments for the world’s leading AI labs. They are looking for a backend-leaning Software Engineer with strong infrastructure experience to own entire technical verticals—from data collection and pipeline architecture through cloud infrastructure, deployment and production delivery. You'll work on: 💻 Building scalable backend systems and complex data-capture workflows using Python and JavaScript/Next.js 📊 Architecting high-throughput, data-heavy pipelines handling demanding production workloads ☁️ Owning cloud infrastructure across AWS or GCP, including serverless systems and cloud functions ⚙️ Deploying and operating production workloads using Kubernetes and Docker 📨 Building low-latency distributed systems using Kafka or RabbitMQ, Redis and Elasticsearch 🚀 Taking projects from an ambiguous problem through architecture, implementation, infrastructure, deployment and delivery 🤝 Working directly with the founders to define product strategy, ship quickly and make important technical decisions 🏗️ Establishing engineering best practices and helping lay the foundations for the team’s continued growth Requirements: ✅ Strong backend, platform or infrastructure engineering experience ✅ Hands-on production experience with Python ✅ Experience owning substantial projects end-to-end, including their cloud infrastructure ✅ Strong knowledge of distributed systems, data pipelines and high-throughput architectures ✅ Production experience with Docker and ideally Kubernetes ✅ Experience with AWS or GCP, serverless architecture and cloud-based data processing ✅ Familiarity with technologies such as Kafka, RabbitMQ, Redis or Elasticsearch ✅ Evidence of turning ideas into reliable production systems in a fast-moving environment ⭐ Experience with AI research, LLM evaluations, human-in-the-loop systems or frontier-model data infrastructure is highly valuable Frontend development is not the focus of this position. They are particularly interested in backend-leaning engineers, platform engineers and infrastructure specialists who can take complete ownership of data-intensive systems. This is not a role for someone who has only contributed to a narrow component within a large engineering organisation. They are looking for a high-agency engineer who can understand an entire problem, make sound architectural decisions and remain accountable for the production outcome. The company has raised a $30M Series A at a $300M valuation, led by Altos Ventures, with backing from The Raine Group, Y Combinator and BoxGroup. Its angel investors include researchers and executives from Google DeepMind, OpenAI, Anthropic, Meta Superintelligence Labs and Microsoft AI. The company has already grown beyond a $100M revenue run rate, is highly profitable and serves every major frontier AI lab. You’ll join a team of more than 30 exceptional engineers, researchers and operators with experience from Citadel Securities, Meta, Google, Silver Lake and Morgan Stanley—and help build infrastructure that directly shapes how frontier AI systems improve. ✈️ Visa sponsorship is available, including O-1 and H-1B transfers. Relocation support may be negotiated at offer stage. 💰 Competitive salary and meaningful equity.