Abstract: A method and a novel flexure interface apparatus are provided for ultrahigh-vacuum (UHV) applications for precision nanopositioning systems. An ultrahigh-vacuum (UHV) metrology base is integrated with an ultrahigh-vacuum (UHV) flange together including a precision and compact flexure interface structure defining a UHV metrology base near-zero-length feedthrough. The UHV metrology base is directly mounted to a flange mounting surface in air with nanopositioning and thermal stability. The precision and compact flexure interface structure has sufficient strength to hold the vacuum force and sufficiently flexible to survive with the thermal expansion stress during bakeout process.