It's 4:30 a.m. and Rebecca Belik of Littleton, Colorado is on the job already.

"Hi Emma, how are you today?" she asks the student that appeared on her computer screen.

While most of her neighbors are asleep, Belik is helping kids on the other side of the world learn English via a 25-minute lesson at a time. She works for VIPKid, one of many China-based online tutoring platforms that have sprouted up. This company matches 70.000 U.S. teachers with 600.000 Chinese students.

The approach of VIPKid can be summed up in three words: "Making English fun," said Wenchi Yu, head of Global Public Policy at VIPKid.

According to Yu, her company's founder saw a shortage of English teachers in China six years ago. At the same time, many Chinese parents want their children to learn English in a more creative way than what is typically done in a classroom.

"It's not something that's provided in Chinese schools," Yu said. "This is why there's such a demand for our services."

"The difference with VIPKid is that they're taking it beyond learning English and helping them get the dialect," Belik said.

The curriculum is structured but teachers are encouraged to use props, humor and positive reinforcement.

Helped by technology, online education has spread rapidly in recent years. It helps more underserved and remote communities than ever. But teaching students this way, experts say, can be challenging and requires lots of thought and planning.

"Ensuring that the learner on the other end is understanding and comprehends what is going on, you've got to keep their attention, engage them," said Karen Riley, Dean of the Morgridge College of Education at the University of Denver.

It's an ongoing learning process for VIPKid teachers, hundreds of whom gathered recently in Las Vegas.

Tutors are all carefully vetted before they're hired. A Bachelor's Degree and at least one year of teaching experience are required.

"They care so much about their students that go way beyond just this technology platform," Yu said. "I'm always incredibly grateful for their work and their passion."

Don't forget patience, too.

"I had one little guy who lived very high up," Belik said. "I think he knew it made me a little sick but he would like to take his iPad and show it out the window. Teacher look how far up I am! I'm like ahhh…"

At a time when the two countries are experiencing tensions, this American says she's giving China's next generation a window into a world it may not have seen.

"It takes it from being that scary American or that scary Chinese person to oh I know teacher Rebecca, she wasn't scary," Belik said.

Belik's students and her flexible schedule have more than made up for her unusual hours and good pay.

"It kind of exceeded my expectations," she said. "I did not expect to like it this much."