It’s a brave new world for makers of high-tech stuff. This month, President Trump announced that most imports will see tariffs—and goods from China, which makes most of the world’s electronics, face the steepest levies, as high as 145%.

The situation is far from settled. But things are already tougher for thousands of American companies that have long steered their development and production through China. These companies are grappling with a new reality that a sudden trade ordinance can sink their businesses. And if they do stay afloat, it’s on the backs of consumers who must pay more.

Big Tech is largely spared. iPhones, laptops and other electronics are exempt from the new levies, at least for now. And these giants tend to have the cash and supply-chain heft to work through the obstacles as they arise.

What about Small Tech? My video baby monitor, my favorite charging cable and my allergy-fighting smart air purifier—I spoke with their makers and others about the tariff impact and the future of gadgets. Most are in limbo. All say the uncertainty is more frustrating than the tariffs themselves.

What does that mean for us? Prices will go up. Shelves will get emptier. Software updates will be more common than hardware upgrades. And you might face even more subscriptions.

The short term: Going out of stock

On May 2, the “de minimis” trade exemption for Chinese imports whose retail value is $800 or less will end.

Some products will see immediate price surges. Loftie, which makes a smart sunrise lamp, has about 750 units left in stock. The made-in-China lamp now carries tariffs totaling 175%. On May 1, Loftie’s sticker price rises from $275 to $450. “Over $100 of that is to the U.S. government,” says Chief Executive Matthew Hassett.

Flaus, an electric flosser, has about eight weeks of inventory left in the U.S. Another two-and-a-half months’ worth is on hold in China, where the manufacturer is getting antsy for payment.

Flaus designed its product around precision-engineered parts that are most easily assembled in China.

Flaus CEO Samantha Coxe says China was the best option to manufacture the Mila.

“Everything you’re buying today was imported pretariffs. But those warehouses will run out in the next 30 to 90 days,” he says.

Even if China tariffs end up lower, there will also be a massive increase in companies’ shipping costs. Prigge says the 90-day pause on levies in countries other than China prompted a rush in shipments. Boat prices from Vietnam, where Mila is moving some manufacturing, went up 25% last week, he says.

The medium term: Pushing subscriptions

Subscriptions are a headache for many consumers. During a moment like this, the recurring revenue is a lifeline for most companies.

Mila isn’t feeling as much pressure to increase prices because about 70% of customers of its $199-and-up air purifiers are signed-up for filter autorefills, he says—essentially a $118-a-year subscription.

Nanit makes a Wi-Fi-enabled baby monitor. An optional subscription, starting at $4 a month, offers sleep insights and access to video history. If sales halved, the memberships alone could keep the business afloat, says Nanit CEO Anushka Salinas. The company has over a million active users globally, and 55 full-time employees in the U.S.

Still, Nanit’s gadgets are made in Malaysia, which after the pause will face a 24% duty, and some parts are produced in Vietnam, which will carry a 46% tariff. Unless the Trump administration widens the exemptions, that is.

Salinas believes that baby and child gear should be spared, calling them “as essential as the iPhone.”

Workers assemble Mila’s smart air purifiers in a plant in Shenzhen, China.

The long term: Degrading quality, shifting factories

“Cheap stuff does come out of China, but so do really high-quality goods, because of the expertise, engineering and execution there,” said Mike de Santis, CEO of Doris Dev, which works with American brands and Chinese factories to develop new products.

If the tariffs hold, however, overall quality could drop, he says. “Folks are going to squeeze their suppliers, who will squeeze their sub-suppliers and people are going to start looking for where they can cut corners.”

Even routing the supply chain away from China is a tricky bet. “You have to be thinking three to five years ahead in terms of the geopolitical landscape,” says Coxe. “The president could say Vietnam is a mini-China, and put 100% tariffs on Vietnam.”

Hassett is looking to move Loftie production to Thailand. That means $50,000 in retooling costs. But the new Thai inventory wouldn’t land until the fall, and he could run out of stock in the meantime. “This puts the jobs of our team at risk,” says Hassett, who employs 12 people in the U.S.

“When you have uncertainty, what’s the thing you do? You pull back,” says Prigge. “Companies will put advertising and product launches on hold.”

The biggest losers, he says, are American businesses that placed manufacturing orders that they now can’t afford. “It’s not Chinese suppliers who are on the hook for that.”

Write to Nicole Nguyen at nicole.nguyen@wsj.com