SENIOR AI ENGINEER (SEARCH)

At Ants, we are partnering with a well-funded, early-stage startup in Stockholm to find a Senior AI Engineer (Search). Who We Are We are a well-funded, early-stage technology company on a mission to fundamentally redefine the way the world searches, discovers, and transacts, built on a philosophy that puts the user first at every step. The user is not simply a means of transaction. They are a valued participant whose data works for them, not against them, enriching their world and their own experience within it, with them retaining full control. Our mission is underpinned by proprietary, patent-pending technology built on a novel engine and system. The Problem You Will Be Solving The internet was built to inform the many, not to serve the individual. Platforms optimize for engagement, extraction, and consumption at global scale. AI has made this model even more efficient, with the user still largely remaining the input, not the full beneficiary. The problem is not information. The world has never had more. The problem is that people give away a lifetime of data without receiving the personalized experience it should enable. People should not have to search. They should simply find. Who You Are • Highly talented and motivated to build products with people, for people • You thrive in zero-to-one environments and find genuine satisfaction in creating from scratch • A fast-paced thinker with a relentless desire to learn, improve, and raise the standard around you • Able to inspire, elevate, and collaborate; you make the people around you better • A great communicator; you express complex ideas with clarity, precision, and confidence across all levels of the organization • Able to transform ideas into working systems and technical milestones with light speed and precision • Highly ambitious and action-driven; you thrive under pressure and find genuine energy in working at the edge of what is considered possible • Capable of designing and building production-grade systems in a fourth of the time most experienced and “sane” professionals would consider possible What You Will Do • Build query understanding pipelines covering intent classification, named entity recognition, semantic parsing, and contextual query expansion across diverse and multilingual query distributions • Design and build dense retrieval infrastructure including bi-encoder and cross-encoder architectures that retrieve and rank results based on deep semantic understanding of user intent • Build re-ranking systems that refine candidate result sets to surface the most accurate and contextually relevant results at query time • Design and operate RAG pipelines that assemble accurate, contextually appropriate information from multiple retrieval sources and deliver it through a generative interface grounded in current data • Fine-tune pretrained language models on domain-specific data to enhance vocabulary coverage, entity understanding, and query pattern recognition where general-purpose models fall short • Build precision evaluation infrastructure including query-level relevance assessment, coverage analysis, and longitudinal quality tracking across the full distribution of real user queries Minimum Qualifications • MSc in Natural Language Processing, Information Retrieval, Computational Linguistics, or Computer Science from KTH, Stockholm University, Chalmers, ETH Zurich, or an institution of equivalent standing • Production experience building semantic search or information retrieval systems that real users depend on • Architectural understanding of transformer models; not surface