Arsenit is an Estonian architecture studio founded by Arseni Timofejev, known for its focus on context-sensitive, sustainable, and high-quality design, particularly for residential and micro-hotel projects. Established in 2020, the firm has gained international recognition for projects like the modular "Piil" treehouse, which was elevated to minimize environmental impact and provide immersive views of the Estonian wilderness. Arsenit leverages prefabricated construction methods, uses local materials, and emphasizes a blend of modern design with natural surroundings.