After the November election of Donald Trump, whose campaign was filled with xenophobic and anti-immigrant rhetoric, tech companies across Silicon Valley have been feeling increasing pressure to say whether they would ever build or contribute to the creation of a Muslim registry.

This idea for a Muslim registry was first mooted by the president-elect one year ago on the campaign trail as a potential strategy for preventing terrorist attacks. To critics, the idea calls to mind some of history's most shameful episodes, from the internment of Japanese-Americans to the Holocaust.

The establishment of such a registry would require engineering prowess and troves of data -- both the sort of thing big Silicon Valley companies boast in quantity. Hence the recent procession of such companies issuing pledges never participate in building anything of the kind.

The following companies have taken a public position:

Apple: "We think people should be treated the same no matter how they worship, what they look like, who they love. We haven't been asked and we would oppose such an effort," an Apple spokesperson told BuzzFeed.

Atlassian: "Atlassian has not been asked to help build a Muslim registry, and we certainly would not do so. We believe the best innovation happens when diverse teams of people come together as equals to create amazing things. We recognize the important contributions that Muslims--around the world and here at Atlassian--have made. We look forward to supporting organizations and initiatives that advocate for creating a more collaborative, inclusive world."

Facebook: "No one has asked us to build a Muslim registry, and of course we would not do so," a Facebook spokesperson told The Intercept.

Foursquare: "Foursquare is a community of explorers, makers, thinkers and brands. We value each member and diversity in our world. Though the request is hypothetical, we would refuse to create a registry based on any religious or cultural affiliation. Our users and social responsibility always come first."

GitHub: "As an organization, we firmly believe in the value of collaborative, diverse, and safe communities. We refuse to participate in the creation of a database based on anyone's religious beliefs and are committed to ensuring data on our platform is handled ethically and appropriately."

Google: "In relation to the hypothetical of whether we would ever help build a 'muslim registry' - we haven't been asked, of course we wouldn't do this and we are glad - from all that we've read - that the proposal doesn't seem to be on the table," a Google spokesperson told BuzzFeed.

IBM: "No, IBM would not work on this hypothetical project. Our company has long-standing values and a strong track record of opposing discrimination against anyone on the basis of race, gender, sexual orientation or religion. That perspective has not changed, and never will," an IBM spokesperson told BuzzFeed.

Lyft: Asked if Lyft would ever help facilitate the creation of a national Muslim registry, the company said "No."

Medium: "Medium would not participate in any efforts whatsoever to create a registry for any ethnic or religious grouping."

Microsoft: "We've been clear about our values. We oppose discrimination and we wouldn't do any work to build a registry of Muslim Americans," Microsoft spokesman Frank Shaw told BuzzFeed.

Pinterest: "Pinterest opposes any registry based on religion or ethnicity. We welcome and encourage diverse perspectives and beliefs, both with our employees and on Pinterest.?"

Salesforce: "We have not been approached by anyone about the creation of a "registry" of any kind. Equality for all people is a core value of Salesforce and we oppose any effort to discriminate against anyone on the basis of religion, race, ethnic background, national origin, sexual orientation, gender identity, age or disability status."

Twitter: "No," Twitter told The Intercept when asked if the company would help build such a tool.

Uber: "No," Uber told BuzzFeed when asked if the company would help build such a tool.

Aside from these tech company, individual tech workers have also taken a pledge to oppose such a tool through the website NeverAgain.Tech. "We refuse to participate in the creation of databases of identifying information for the United States government to target individuals based on race, religion, or national origin," the pledge reads.