Brazil has the largest population of individuals living with HIV/AIDS in Latin America with a disproportional prevalence of infection among men who have sex with men (MSM). This study evaluated PrEP awareness by age (18-24, 25-35, ≥36 years), its associated factors and the willingness to use HIV prevention technologies among MSM using a GSN app in Brazil. Inclusion criteria were ≥18 years-old, cisgender men and HIV-negative serostatus. Of 7242 individuals, 4136 (57%) completed the questionnaire. PrEP awareness was reported by 51% (though lower among MSM aged 18-24 and ≥36 years) and its associated factors were higher family income, most friends with the same sexual orientation, high number of male sexual partners and marijuana use. HIV testing (never vs. at least once) lead to an almost 3-fold increase in the odds of PrEP awareness. High HIV risk perception led to increased PrEP awareness only among MSM aged 18-24 years. A total of 2335 (56%) was willing to use daily oral PrEP. PrEP awareness remains low in Brazil and mobile tools are key strategies to reach MSM and increase awareness of prevention technologies. Community-based interventions could add to online campaigns to reach the most vulnerable, which include young, non-white and lower-income MSM.