Studies show that the trustworthiness of a web application is affected by how it is designed and in particular which font is used, which colour scheme is used and if the layout is expected or unexpected. To test this claim, a web application was developed according to principles about how design elements affect the trustworthiness of a web application. The web application was developed iteratively and design choices as well as implemented functionality were supported by related research. Eight different prototypes of the web application with different combinations of a blue and red colour scheme, the fonts Arial and Comic Sans as well as an expected and unexpected layout was developed. Two user tests were conducted in order to assess how the specific design elements affected the trustworthiness of the web application. The results show that the choice of colour and font for a web application affects how trustworthiness is perceived by the user. The combination of a blue colour scheme, the Arial font and the expected layout was perceived as the most trustworthy out of the examined combinations. Colour and font have a significant impact on perceived trustworthiness, where a blue colour scheme is to be preferred over a red colour scheme as well as the Arial font over Comic Sans. Regarding layout, no conclusions could be drawn from the results whether an expected layout is preferred over an unexpected layout.