In this paper, taking into account the theory of slow-roll inflation and using a Lagrangian that may include poles, the primary inflationary and reheating eras are studied within the Rastall theory. The focus of the study is primarily on the exponential potential. The consistency of results with the Planck 2018 data and the Planck 2018 data+BK18+BAO (Ade et al., 2021), as well as the ability of the production of the acceptable number of e-foldings support the viability of the model. Furthermore, it is inferred that the model accurately describes the reheating phase. The advantage of the constructed model in fitting the data is reasonable in some cases compared to General Relativity. In summary, it is obtained that the study constraints the Rastall parameter in a completely compatible way with thermodynamic predictions (Moradpour and Salako, 2016), studies on the pulsar PSR J (EI Hanafy 2022), and the early-type galaxies (Li et al., 2019).
