The paper describes basic characteristic of the boundary meshless simulation system for designing nozzles for gas-focused micro-jets,used for delivering samples in femtosecond crystalography experiments.The recently developed axisymmetric version of the method of regularized sources(MRS)is used for solving incompressible moving boundary Stokes flow problem,associated with the gas focusing of micro-jets.The nodes are put on the boundary of the gas and liquid and the solution is sought as a linear combination of the fields due to the regularized axisymmetric sources in the boundary nodes.The intensity of the regularized sources in the nodes is adjusted to comply with the flow magnitude as prescribed by the boundary conditions.No artificial boundary is needed.The flow fields are calculated separately for the gas and for the liquid regions.The interphase boundary between the gas and the liquid is parametrized with its length and the shape is represented by multi quadric radial basis functions.The equal gas and liquid velocity on the interphase boundary and the tangential stress balance are iteratively adjusted first,followed by iterative adjustment of the shape of the moving boundary,based on the normal stress balance equilibrium which takes into account the surface tension and the curvature.The redistribution of the boundary nodes and smoothing of the boundary shape is needed during this procedure.Several numerical results with different nozzle geometries and liquid and gas flows are shown.