Based on extensive experiments, we demonstrated that even if the starting initial guess is a poor one, gradient based local optimizers are able to improve the fitness of the force field drastically (with one exception being the core bond order parameters). Combined together, these innovations allow users to optimize Reax force fields in mere minutes. This is notable because existing methods require several days for obtaining essentially same quality force fields. Finally, JAX-ReaxFF provides a utility not available in other similar tools; its auto-diff functionality enables the study of the new functional forms for the interactions of the ReaxFF model without explicitly implementing the force calculations and the optimizer, since both forces and parameter gradients can automatically be calculated by JAX.