It's very tempting to go to China as an au pair. The culture is exciting, the food is great, and the language is fascinating.
A little over three months ago I left for Shanghai, China to live there as an au pair for one year. Unfortunately, I had to leave after just three months when I couldn't renew to a legal visa. There is simply no visa for au pairs. The agency will try to get you a tourist visa, but you are not allowed to work on a tourist visa, nor with a student visa. The only way to actually be an au pair in China legally is to get a Business Visa. The caveat is that a business visa requires you to have a college degree or some similar certificate. There are some minor exceptions, but in general, that's how it is.
My experience was still now terrible. The English teacher that the agency provided was phenomenal, my host family was fantastic, and the people at the agency were friendly. Though their ability to communicate in-between themselves was subpar. Due to that, there were often contradictions within the agency and plenty of misunderstandings. Also, the contract that you sign as an au pair is awful since the agency can't enforce it because that would be biting the hand that feeds them (the families).
It's worth mentioning that many au pairs end up in host families where they simply don't have a good time. Talking to the other au pairs during my time there I got to hear some horror stories about their host families and the way the agency handled those situations. I saw several of them leave earlier than planned. They were clearly disappointed. If I would have had that information before I left, I would have decided to stay home instead. The odds of the experience turning out miserably is just too high.
Additionally, there are some massive issues with the whole business idea of Au Pair Shanghai. They try to recruit as many au pairs and families as possible. Then they charge the families a massive fee. You, the au pair, who work 30 hours a week will see almost none of that money. Instead, it goes to paying the employees who spend most of their time trying to reach out to more au pairs. In the end, it will be a bad deal for you.