Boutique AI names a firm model, not a model architecture. In practice it means a small specialist AI consultancy, often founder-led or staffed mainly by senior engineers, that takes on fewer clients and stays close to the build. That sits opposite a large multi-practice firm that sells AI as one offering among many.
Buyers reach for the term when they want depth on agents, RAG, or LLM systems without commissioning a broad transformation programme. Whether that model beats a large consultancy is a separate decision.