Credibility is being called into question in a global way, which threatens the authority of institutions in general, including the press, in the so-called post-truth era;. Due to its disregard for truth, the current times have been marked by the circulation of fake news. It is also a time known as the post-factual era. The same networked society driven by the internet with promises of a more horizontal future has witnessed the rise of algorithmic platformization, the disqualification of the press, and the culture of misinformation. It is from this extremely hostile and vulnerable environment for democratic institutions that the reflections brought in this thesis arise. The level of misinformation is such that today there is a proliferation of fact-checking agencies and services in various countries. In principle, fact-checking exists to determine whether speeches are true or false. However, these agencies and services have gained visibility and become more influential in the journalistic environment. The shift of fact-checking to external environments outside newsrooms or to specific spaces within news outlets carries with it an assumption that one of the most important functions of journalism, factchecking, can be displaced. This function contributes to the construction of credibility and, consequently, functions as the pillar of journalistic authority. Thus, the general objective here was to understand the place occupied by fact-checking agencies in the Brazilian journalism universe and the journalistic authority they have claimed. A central issue is how fact-checking work influences journalistic credibility/authority and whether there is - and to what extent – a compromise of this authority through the market establishment of fact-checking services. To this end, we analyzed the raw content of 677 posts about the presidential elections in Brazil made by the Lupa and Aos Fatos agencies and the Fato ou Fake, Estadão Verifica, and Folha Informações services in the period between August 16 and October 30, 2022, which includes the day campaign started and the day of the second round of voting in the elections.