The L1-Allegra laser (1 kHz, 50 mJ pulse energy, 15 fs pulse duration) developed at ELI-Beamlines [1] in Czechia is already being used for various scientific experiments. The femtosecond synchronization project (referred to as F-SYNC) aims to dramatically improve the experiments with L1-Allegra. Therefore, we have developed an independent auxiliary laser system inspired by the design of the L1-Allegra front-end [2], [3] with an output energy of approximately 13 mJ at 1 kHz and a bandwidth that supports compression to < 20 fs. In essence, F-SYNC consists of a master oscillator, a fiber seed distribution system, a pump laser with grating compressor [4], a supercontinuum (SC) seed [5], and 3 stages of optical parametric chirped pulse amplification (OPCPA).