This Bachelor Thesis is explaining the term e-Construction diary. The main difference between the diary that was kept on paper and the current electronic one is that, in order to start the e-Construction Diary, at the beginning, all the data on the participants in the construction, their authorizations, and all the necessary documents such as the building permit, notification of the start of construction, and certificates must be entered. The construction journal can only be started by the person who created it. The other participants receive an invitation to participate in the project, i.e. to fill in the diary, and must accept the invitation and then enter data. The e-Construction Diary is kept by the construction contractor in an orderly and up-to-date manner and is signed by the supervising engineer. Data for each working day are entered up-to-date in the diary (what was the weather like that day, how many workers were there, which machines were used, which works were performed), and by completing the entry, it is no longer possible to modify the entered data. The log page is complete when the supervising engineer signs it. The supervising engineer can set a deadline for completing the log pages. The construction diary is signed with a qualified electronic signature. Before closing the logbook, the supervising engineer creates a final report.