On Friday, President Donald Trump issued an executive order denying citizens of seven majority-Muslim countries entry into the United States, effectively making good on his campaign promise of implementing a Muslim ban.

Over the hours following the order’s signing, many voices joined in a chorus of dissent, including the heads of some of the tech industry’s biggest companies.

Mark Zuckerberg, the CEO of Facebook and an increasingly active voice in political matters, was the first to speak out. In a short essay posted to Facebook, the founder of the world’s largest social network said, “the United States is a nation of immigrants, and we should be proud of that” and argued “we should keep the door open to refugees and those who need help.”

Zuckerberg was soon joined by Google CEO Sundar Pichai, who issued an internal memo condemning the travel ban. Nearly 200 members of Google’s staff was directly affected by the order, and Pichai said, “It’s painful to see the personal cost of this executive order on our colleagues.”

A spokesperson for Google issued an official statement from the company stating, “We’re concerned about the impact of this order and any proposals that could impose restrictions on Googlers and their families, or that create barriers to bringing great talent to the U.S."

After two of the biggest companies made their voices heard, many more followed—in most cases, with outrage growing.

Apple CEO Tim Cook told employees, “Apple would not exist without immigration, let alone thrive and innovate the way we do,” in an email. “I've heard from many of you who are deeply concerned about the executive order issued yesterday restricting immigration from seven Muslim-majority countries. I share your concerns. It is not a policy we support,” he wrote.

Microsoft had more than 75 employees affected by the order. “We believe that immigration laws can and should protect the public without sacrificing people’s freedom of expression or religion,” company president Brad Smith wrote in an email to staff.

Twitter offered its statement in less than 140 characters, tweeting, “Twitter is built by immigrants of all religions. We stand for and with them, always.” Company CEO Jack Dorsey spent the day retweeting updates from protests across the country and calls to action to support the American Civil Liberties Union.

In a Facebook post, Netflix CEO Reed Hastings offered one of the strongest critiques of the executive order, calling the move, “so un-American it pains us all.” He continued in his Facebook post, stating, “Worse, these actions will make America less safe (through hatred and loss of allies) rather than more safe.”

While statements came one after another, some major players in tech took action. Google co-founder Sergey Brin joined protesters at San Francisco International Airport, where he reportedly said, “I’m here because I’m a refugee.”

Y Combinator president Sam Altman also joined the protests in San Francisco shortly after publishing a blog post calling for people to “take a stand.” Altman has previously came under fire for his decision to keep venture capitalist and Trump supporter Peter Thiel on as a partner the start-up incubator.

Ride hailing service Lyft opted to do more than just speak out—it pledged $1 million over the next four years to the ACLU. The company was joined by venture capitalists Chris Sacca and Tony Fadell, who offered to match donations made to the ACLU.

While disapproval of Trump’s order was essentially universal from the major players in tech, some companies took longer to get there than others.

Uber made a promise to compensate its drivers barred re-entry to the U.S. for up to three months, but company CEO Travis Kalanick—a member of Trump’s advisory team—was criticized for a mealy-mouthed statement.

The service found itself in hot water on Saturday when it was accused of trying to profiteer after New York taxi drivers decided to strike in solidarity with protesters at John F. Kennedy International Airport. The response spawned a #DeleteUber campaign on social media. Kalanick tried to quell the frustration by calling Trump’s order “wrong and unjust.” The CEO promised Uber would create a $3 million fund “to help drivers with immigration and translation services.”

Elon Musk, founder of SpaceX and Tesla and another tech CEO with a seat at Trump’s table, also struggled to strongly condemn the executive order. He said the ban was “not the best way to address the country’s challenges,” and asked people to read the order and recommend amendments that he could take to the President.