A new tool lets voters in Georgia sign up for automatic notifications of any sudden changes to their voting status that could prevent them from casting ballots in the pivotal Jan. 5 runoffs that will determine party control of the Senate.

Driving the news: VoteFlare.org, a site created by Harvard University's Public Interest Tech Lab, went live Friday.

Why it matters: Advocates earlier this month filed a lawsuit claiming nearly 200,000 Georgia voters were wrongly purged from the rolls in 2019, disproportionately hitting younger, poorer and minority voters.

• Next month's two Senate runoffs, pitting Republican Sens. David Perdue and Kelly Loeffler against Democratic challengers Jon Ossoff and Raphael Warnock, will determine whether Democrats take control of the Senate, giving Democrats control of both chambers of Congress as well as the White House.
• The high-stakes nature of the contests also has raised concerns about turnout and disenfranchisement.
• As of Friday morning, Georgia's secretary of state's office said more than 1.1 million ballots had been cast in the first four days of early runoff voting. In 2018, fewer than 1.5 million votes total were cast.

What they're saying: "The irony in Georgia is that Democrats don't trust the governor or the secretary of state, especially after what happened after 2018, and Republicans don't trust the governor or the secretary of state after what happened in November," Dhruv Gupta, a 2020 Harvard graduate who worked on the project, told Axios.

How it works: Georgia voters who sign up may choose to get notified by text, call or email if there are changes to their registration or absentee ballot status. VoteFlare pulls official data from election offices.

• Harvard professor and Data Privacy Lab director Latanya Sweeney and her students were first to report about vulnerabilities in voter registration websites during the 2016 election.
• This year, Sweeney asked students to look for a technological solution to address voters' distrust.
• They'll work with stakeholders to answer voters' questions about what to do if they are notified of changes to their registration or if their absentee ballot is rejected.

What's next: Virginia. The team has a prototype for 48 of the 50 states.