Abstract
In this research paper, we investigate the existence, uniqueness, and Ulam-Hyers stability of hybrid sequential fractional differential equations with multiple fractional derivatives of psi-Caputo with different orders. Using an advantageous generalization of Krasnoselskii's fixed point theorem, we establish results of at least one solution, whereas the uniqueness of solution is derived via Banach's fixed point theorem. Besides, the Ulam-Hyers stability for the proposed problem is investigated by applying the techniques of nonlinear functional analysis. In the end, we provide an example to illustrate the applicability of our results.