TikTok resurged in the United States on Sunday after President-elect Donald J. Trump said he would issue an executive order to end the federal ban on the app.
The abrupt change came hours after major app stores pulled the popular social media site and it stopped working for US users as the federal law took effect on Sunday. The company said in a post on X that “in agreement with our service providers, TikTok is in the process of restoring service.”
Mr. Trump said in a Sunday morning post on Truth Social that he “will issue an executive order on Monday to extend the time before the law’s bans go into effect so we can make a deal to protect our national security.” .
The ban stems from a 2024 law that requires app stores and cloud providers to stop distributing or hosting TikTok unless it is sold by its Chinese parent company, ByteDance. Lawmakers passed the law amid concerns that the Chinese government could use the app, which supports about 170 million United States users, to collect information on Americans or spread propaganda.
App stores and cloud computing providers that do not comply with the law face potentially significant financial penalties. Mr. Trump said in his post on Sunday that his order “will confirm that there will be no liability for any company that helped keep TikTok from going dark prior to my order.”
The possibility of an executive order, followed by TikTok’s surprising about-face, marks a new phase in the battle for the future of the app, which has reshaped the social media landscape, defined popular culture and created a livelihood for millions of influencers and platform-based small businesses.
In issuing the order, Mr. Trump would raise questions about the rule of law in the United States. His action would be an attempt to temporarily neuter a law that was passed with broad bipartisan support in Congress and that the Supreme Court unanimously upheld last week.
“We thank President Trump for providing much-needed clarity and assurance to our service providers that they will not face sanctions by providing TikTok to more than 170 million Americans and enabling more than 7 million small businesses to thrive,” TikTok said in a statement that announces that the application is returning to the Internet.
Creators celebrated as TikTok came back to life.
“ITS BACKKKKK,” James Charles, a beauty influencer, posted on Instagram, where he has been communicating with fans since the ban went into effect.
Policy experts and lawmakers from both sides of the aisle issued early warnings that the law is still valid and enforceable. TikTok remained unavailable for download on the Google and Apple app stores, suggesting that some companies continued to enforce the ban.
Legal experts said the impact of Mr. Trump will depend on the details of any order he releases, which is likely to raise significant questions about the reach and limits of the president’s authority.
“There is no good path here from a rule of law perspective,” said Alan Rozenshtein, an associate professor of law at the University of Minnesota.
Google declined to comment. Apple did not respond to a request for comment, although it said in an explanation on its website that it is “required to follow the laws in the jurisdictions where it operates” and that TikTok will no longer be available for downloads or updates in the United States.
Oracle, which hosts TikTok on its servers, did not immediately respond to a request for comment.
It is not clear whether the efforts of Mr. Trump — and the negotiations to keep the app online that took place before he even took office Monday — will be successful in the long run. His executive order could face a legal challenge, including whether it has the power to stop enforcement of a federal law. Companies subject to the Act may decide that the text of an order does not provide sufficient assurance that they will not be penalized for violations.
The law allows the president to grant a 90-day extension if a buyer is found, but only if there is “substantial progress” toward a deal that puts TikTok in the hands of a non-Chinese company. That deal must also be able to be completed within 90 days for the president to trigger the extension. And it’s unclear whether that expansion option still exists, given that the law is already in place.
In his post on Sunday, Mr. Trump floated the idea that he “would like the United States to have a 50% ownership position in a joint venture,” without elaborating.
TikTok has said a sale is impossible, citing the nature of its global operations, and China has already signaled it could block the export of its all-important video recommendation technology.
Some policy experts said there was too little information to draw conclusions about next steps. “What Trump has proposed on social media seems illegal,” said Peter Harrell, a former Biden administration official. “We’ll have to see what he actually does to implement it.”
Late Saturday, TikTok posted a message to users saying the site was down, but it was “thankful that President Trump said he would work with us on a solution.”
Then, after the service was restored, TikTok welcomed users with a message saying, “As a result of President Trump’s efforts, TikTok is back in the US!”.
TikTok and several Democratic members of Congress in recent days have made a last-ditch effort to keep the app online. Senator Chuck Schumer of New York, the Democratic leader, privately told President Biden that the dark app on his watch would damage his legacy.
Critics of TikTok have launched their own push to keep the potential ban on track. Sen. Tom Cotton, R-Arkansas and chairman of the Senate Intelligence Committee, has called on some of the big tech companies in recent days to say they had to comply with the law, according to three people familiar with the calls. It also said in a joint statement earlier on Sunday that there was no room for any kind of extension since the law had already come into effect.
After TikTok announced it would bring the service back to the app, Mr. Cotton posted a warning.
Any “company that hosts, distributes, serves, or otherwise facilitates the communist-controlled TikTok could face hundreds of billions of dollars in punitive damages under the law,” not only from the federal government, but also from its attorneys general. state, shareholder lawsuits and under securities law, he said in a post on X.
“Think about it,” he said.
Maggie Haberman, Karen Weisz, Sapna Maheshwari, Madison Malone Kircher and Aaron Krolik contributed to the report.