XTEN Architecture is an award-winning architecture firm located in Los Angeles, California, with associate offices near Basel, Switzerland. Founded in 2000 by partners Monika Häfelfinger and Austin Kelly AIA, LEED AP, XTEN Architecture is a full service architecture and design firm specializing in cultural buildings, office and commercial facilities, large-scale residential projects and custom single family residences. Building designs are developed using innovative materials and sustainable technologies, and guided from schematic design through construction completion.

XTEN has developed a distinctive method to the development of contemporary architecture, with an emphasis on minimalist logic, material transformation and refined detailing and craftsmanship. Underlying themes in the work have focused on the conceptual use of building materials, modified with both traditional and digital techniques. In new buildings, landscapes and master plans, the architects develop strong sculptural forms and spaces transformed by both direct and indirect connections to nature and the buildings' immediate environment.

XTEN Architecture has been awarded the International Architecture Award from the Chicago Athenaeum and European Centre for Architecture, the American Architecture Award, the IV Miami+Design Bienal Architecture Award, the AIA California Council Architecture Award, and several Design Awards from the American Institute of Architects. The firms work has been published in books and magazines internationally. Buildings in design and construction include single-family residences, residential estates, commercial and cultural projects and competitions in the United States, Switzerland, Asia and the Middle East.