All3 is a London-based construction technology company building an integrated stack to triple construction productivity. It combines an AI architecture platform that translates a brief or site address into a fully compliant building design, robotized off-site factories, and Mantis, an autonomous legged robot designed for on-site assembly. The company says its system can reduce project costs by up to 30%, shorten delivery timelines by up to 50%, and cut embodied carbon by up to 25%. Mantis is operational, customers are signed, and first commercial deployments are slated for active sites in Germany. Founded by the team behind rapid-grocery unicorn Samokat, All3 raised a $25M seed round in April 2026 led by RTP Global, with participation from SuperSeed, Begin Capital, s16vc, and VNV Global.