Mamdani Has Used Signal For Government Business As Mayor

NEW YORK — Since becoming New York City’s youngest mayor in a generation, Zohran Mamdani has kept leaning into his tech-savvy persona, regularly releasing the type of made-for-going-viral social media videos that propelled him during his 2025 campaign.

But he’s also continued to use another, potentially more problematic technological trapping since taking office: Signal.

Three people with knowledge of the matter told POLITICO that as mayor Mamdani has used the encrypted messaging app to communicate with fellow elected officials and political advisers. In at least one instance, he’s discussed government business over the app, according to one of those people, who like the others, was granted anonymity to discuss the sensitive issue.

POLITICO independently confirmed that Mamdani’s Signal account, registered to his personal cell phone number, remains active.

Norman Siegel, a veteran First Amendment lawyer who previously helmed the New York Civil Liberties Union, said mayors should never use Signal to communicate with other government officials as a rule of thumb — and that there’s another particularly important reason why Mamdani himself should avoid the app.

“With our new mayor, so much of what he’s articulating is a breath of fresh air,” Siegel said. ”I would urge him to not engage in Signal or similar kinds of applications that basically are meant to hide information and prevent the public from knowing the inner workings of government.”

The app’s heavy encryption protocols — not to mention its ability to self-delete messages after a set period of time — are incompatible with local record-keeping and freedom of information laws. New York City’s law gives the public a right to request access to communications the mayor engages in, but it can be all but impossible for FOIL officers to track down such records if they’re held on Signal, or deleted altogether.

Mamdani’s continued presence on Signal runs counter to his promise to usher in a new era of transparency and good government in the nation’s largest city. Former Mayor Eric Adams also used encrypted messaging apps while in office, including to communicate with aides about the alleged campaign finance fraud scheme at the heart of his since-dismissed corruption indictment. And Signal became an international source of controversy last year after The Atlantic reported that Pete Hegseth, President Donald Trump’s defense secretary, used the app to discuss top-secret U.S. military missions in Yemen.

Mamdani spokespeople did not return requests for comment on Mamdani’s Signal use.

In an indication he was aware of the problems Signal can pose for government officials, Mamdani left several group chats on the app after his November election victory, according to one of the people who was granted anonymity.

But the current mayor isn’t the only New York politician to be confronted with communication transparency concerns.

One month into his first and only term, Adams was approached about his Signal use, too. He told City & State at the time that he only used the app for “private” matters and that “government business is conducted on my government phone.” Less than three years later, Manhattan federal prosecutors filed the corruption indictment that included allegations Adams had used encrypted apps to communicate with staff about his alleged campaign finance fraud.

Former Mayor Bill de Blasio and his staff also touched off transparency concerns when it emerged in 2019 that they had discussed government scheduling over Signal.

And long before there was Signal, former Gov. Andrew Cuomo — who was Mamdani’s top opponent in last year’s mayoral race — raised hackles from good government advocates for using BlackBerry’s PIN-to-PIN system to avoid creating paper trails.

“He’s got to stop doing that,” said Reinvent Albany Executive Director John Kaehny of Mamdani’s Signal use.

Joe Borelli, the City Council’s former Republican leader who was in elected office for the Signal controversies involving both de Blasio and Adams, sympathized with Mamdani’s decision to stay on the app.

“I mean why would he not be using it? Only an idiot wouldn’t use it after seeing the probes of the last admin,” Borelli said, referring to the various corruption investigations ensnaring Adams and his top aides. “It isn’t illegal in 99 percent of his conversations, and it protects both parties.”

Grace Rauh, executive director of the Citizens Union, agreed that elected officials shouldn’t be completely prohibited from using Signal, noting there’s nothing in the law barring them from using the app for personal matters.

But Rauh, who was the lead plaintiff on a lawsuit that forced de Blasio’s administration to turn over thousands of emails he exchanged with outside advisers, echoed her fellow watchdogs’ concerns about how easily conversations can veer into official business when a mayor speaks to other government officials.

“City leaders must be deliberate about how they communicate,” Rauh said. “Any discussion of official government business must occur in a manner that ensures records are preserved and accessible under the Freedom of Information Law. The rules exist to protect the public.”