A method for needle-free injection and a needle-free injector device are provided. The method includes automatically injecting an injectable into a surface in contact with the needle-free injector in response to a skin compression parameter of an end of the needle-free injector. A needle-free injector device (102) includes predefined structures formed on it to inject an injectable through a non-porous material. The predefined structures engage an airlock mechanism such that an airlock in the non-porous material and operably coupled to the airlock mechanism can only be opened and closed to enable needle-free injection through the non-porous material without disrupting an integrity of the non-porous material by the needle-free injector device. Other functions, embodiments and methods for using and programming the needle-free injector device are also provided.