Full Stack Developer

We're working with a leading AI company that helps the world's most innovative organisations improve their AI agents by providing human feedback. They collaborate with leading AI organisations to train Large Language Models (LLMs) to function as proactive, multi-step agents, focusing on teaching these systems how to design, coordinate, and optimize complex, real-world architectural workflows.The Role Develop objective, verifiable criteria (rubrics) to evaluate system performance and ensure outputs meet strict functional requirements. Review system logs and "trajectories" to refactor code, improve execution paths, and reach a "Golden Path" of perfect reliability. Test systems for vulnerabilities, including improper data exposure, unauthorized access escalations, and edge-case failures. Help train generative AI models as a skilled software expert.What You'll Need 2+ years of experience in backend engineering, AI automation, or complex systems integration. Proven ability to build and maintain production-grade software with modular separation (e.g., distinct services for data parsing, logic processing, and reporting). Strong command of at least two major languages (e.g., Python, JavaScript, Go, or Java) and experience working with SQL databases. Practical experience building for live, non-mocked environments and handling multi-turn system interactions. Outstanding attention to detail and the ability to provide clear, high-density technical feedback on complex system behaviors. Expertise building multi-stage coordination tasks where data acquisition leads to reasoned output (Nice to have). Hands-on experience integrating agents with live tools such as Supabase, Gmail, and various APIs to solve real-world problems (Nice to have).What's On Offer Fully remote and flexible hours. Highly competitive hourly rates for core project work. Additional opportunities for incentive payments through "Missions". Work on cutting-edge generative AI models and autonomous agents.Apply via Haystack today!