The concerns are particularly acute in India, where IT firms like Tata Consultancy Services, Infosys and Wipro are top beneficiaries of the H-1B visa programme.
For Grishma, an Indian software designer, President Donald Trump's review of the visa programme for bringing highly skilled workers into the United States comes at a bad time.
Fresh from gaining a master's degree in Europe, and with an offer of employment from a well-known U.S. design firm, she was well on her way to fulfilling the ambition of many young Indian IT workers - a dream job in America.
But as she waits in the H-1B visa queue for the green light, she is caught in a bind.
"It's a weird time to be applying, with all the scrutiny," said Grishma, who gave only her first name for fear of jeopardising her chances of getting a visa.
The United States has already suspended the "expedited processing option" for applicants, under which she may have received a visa in weeks.
More broadly, uncertainty over the review announced this week has unsettled Grishma and many others like her.
She will have to wait until at least around August to learn her fate, but having accepted the U.S. job offer she is not in a position to apply for positions elsewhere, including in Europe.
"It's pretty debilitating," Grishma told Reuters. "I'd like to start work to mitigate the financial damage."
Trump's decision was not a huge surprise, given his election campaign pledge to put American jobs first.
But the executive order he signed, though vague in many areas, has prompted thousands of foreign workers already in the United States or applying for visas to work there to re-think their plans. Companies who send them also face huge uncertainty.
The concerns are particularly acute in India, where IT firms like Tata Consultancy Services, Infosys and Wipro are top beneficiaries of the H-1B visa programme, using it to send computer engineers to service clients in the United States, their largest overseas market.