Fitch Ratings has developed an interactive online tool for credit rating simulation.
According to Fitch Ratings, the tool is "a visual overview of the key qualitative and quantitative factors Fitch analyzes to arrive at an entity's credit rating" and the aim of the tool is provide transparency to rating users. (Fitch Ratings, 2018).
You can access the Fitch Navigator online free or charge after signing the disclaimer.
This video from Fitch Ratings explains the purpose and function of the Fitch Navigator online rating simulation tool.