Online voter registration in Massachusetts shot up immediately following Joe Biden’s announcement he would no longer seek reelection, signaling renewed engagement and enthusiasm in the election, especially among young voters, organizers say.

“People are optimistic in a way they weren’t with President Biden as the nominee ... now with Vice President [Kamala] Harris presumably at the top of the ticket, this is a candidate young people can really rally behind,” said Ela Gardiner, spokeswoman for Young Democrats of Massachusetts.

In the days following Biden’s announcement on Sunday, the Massachusetts secretary of state’s office recorded 7,779 online voter registrations from Sunday to Wednesday. That figure was 3,934 from Sunday to Wednesday the week before.

“I find it hard to say there is not a direct correlation between Vice President Harris stepping in ... with this increase in voter registration, especially here in Massachusetts,” Gardiner said.

“The vibe has completely changed in that it just feels different,” agreed David Hogg, co-founder of Leaders We Deserve, a national grassroots organization centered on electing young progressives. “I think when you see a spike in voter registrations, a lot of that comes from young people being excited to go out and vote.”

July figures represent a large increase from June, during which online voter registrations totaled no more than 300 on any given day of that month — except on June 27, the night of the Trump-Biden debate, during which there were 525 registrations.

The data does not reflect automatic voter registration, nor does it include mail-in or in-person voter registration applications. Online voter registration figures can also reflect duplicates or someone updating their party affiliation or personal information such as a change of address.

Debra O’Malley, a spokesperson for the secretary of state’s office, said registrations typically increase as the election approaches and could total around 12,000 per day once the registration deadline gets close. That deadline is Oct. 26 for the presidential election. There are currently five million registered voters in Massachusetts.

“What you’re seeing in those numbers is people who no longer want to sit on the sidelines,” said Steve Kerrigan, chair of Massachusetts’ Democratic party.

He noted excitement and energy behind Harris.

“People are responding to this new, hope-filled opportunity by stepping up and registering to vote,” he said.

On the other hand, MassGOP spokesperson Logan Trupiano attributed the uptick to a strong showing at the RNC, the assassination attempt on Donald Trump and the motivation to defeat Harris.

“Folks are kind of waking up to the Democrats’ fear-mongering and divisive rhetoric that leads to this discontent and divisiveness around the country, and I think it also helped with the people starting to sympathize more with President Trump,” Trupiano said.

More people are registering to vote nationwide, as well. In the 48 hours following Biden’s announcement, vote.org registered nearly 40,000 voters, a nearly 700% daily increase in new registrations, according to the site’s CEO Andrea Hailey.

“That’s the largest number of new voters registered over a 48 hour period we’ve seen this entire cycle,” Hailey shared via X, formerly Twitter. She said young voters accounted for 80% of the registrations since Sunday.

Residents of Massachusetts can register to vote online, in person or via mail. To vote in a federal election, voters must be a U.S. citizen, at least 18 years old and not currently incarcerated by felony conviction. Find more information in GBH News’ 2024 voter guide.