Developing non-perturbative methods might be crucial for understanding inflation and its predictions. In this talk, I will present a nonlinear study of the inflationary epoch of the Universe based on numerical lattice simulations. I will first focus on a model known as axion inflation, where the inflaton is coupled to a gauge field via Chern-Simons interaction. As a second example, I will consider a single-field model with a resonant feature in the potential. I will show that, in both cases, nonlinear effects have important consequences for the inflationary dynamics.