Introduction: The approval of the Transparency Law in Spain in 2013, along with concern about corruption, good governance and accountability has led to a significant increase in studies on transparency of administrations in recent years. Methods: The objective of this article is to expose the different methodological complexities in order to analyse the transparency of the contents published by the public administrations in aspects such as the definition of transparency itself, the object of study, the users or the recipients. Results: A model of analysis of the transparency of the webs of the municipalities is presented: the Infoparticipa project. The methodology we present is based on innovative tools that have established a map of local transparency in Spain. Discussion and conclusions: The Infoparticipa Map has transcended the academic field showing its social utility by allowing the improvement of the information published in the webs.