Students at participating colleges can use its site, called Callisto, to record details of an assault anonymously. The site saves and time-stamps those records. That allows students to decide later whether they want to formally file reports with their schools — identifying themselves by their school-issued email addresses — or download their information and take it directly to the police. The site also offers a matching system in which a user can elect to file a report with the school electronically only if someone else names the same assailant.

Callisto’s hypothesis is that some college students — who already socialize, study and shop online — will be more likely initially to document a sexual assault on a third-party site than to report it to school officials on the phone or in person.

“If you have to walk into a building to report, you can only go at certain times of day and you’re not certain who you have to talk to, how many people you have to talk to, what they will ask,” Jessica Ladd, the nonprofit’s founder and chief executive, said in a recent interview in New York. “Whereas online, you can fill out a form at any time of day or night from anywhere and push a button.”

Callisto is part of a wave of apps and sites that tackle different facets of the sexual assault problem on campus. Some colleges and universities have introduced third-party mobile apps that enable students to see maps of local crime hot spots, report suspicious activity, request a ride from campus security services or allow their friends to track their movements virtually as they walk home. Many schools now ask students to participate in online or in-person training programs that present different situations involving sexual assault, relationship violence and issues of consent.

Institutions of higher learning are increasingly starting such programs to comply with statutes like Title IX, the federal law that prohibits sex discrimination by education programs that receive federal funding. Much of that activity comes in response to a letter issued in 2011 by the Department of Education that said colleges must create campuses free of sexual violence or face possible penalties. Schools are also trying to manage the reputational risks posed by students who accuse administrators of mishandling their sexual assault cases. As of Nov. 4, the Department of Education Office for Civil Rights was investigating 175 cases involving sexual violence at 146 postsecondary schools.