In one example in accordance with the present disclosure, a fluid interface device (106) is described. The device includes a collar (110) to receive a fluid container (104). The collar has an aperture in one end surface. A needle (108) of the fluid interface device passes through the aperture and allows fluid to pass from the fluid container (104) into a reservoir (102). The needle is slideable within the aperture from a dosed position to an open position upon reception of the fluid container. A seal (212) is radially disposed around the needle (108) and seals against the end surface of the collar (110) when the needle is in the dosed position.