These two electronic platforms can be described as the game changers of the economy of China and maybe of the world. They are so powerful that almost every people who owns a smartphone in China they use it every day multiple times.

WeChat or Wēixìnin Chinese, is a multi-purpose messaging, social media and mobile payment application. Owned by the giant tech company Tencent, created by Ma Huateng or Ponny Ma, it was developed in order to give China a Whatsapp lookalike instant messaging application. It developer in chief was Zhang Xiaolong. It was launched for first time in January 2011 and since then it has been growing. On March 2018 it reached the milestone of having 1 billion monthly users and 902 million daily users, 90% in China. Tencent annual revenue hit in March 2018 10.62 billion yuan and a net profit of 3.66 billion yuan.
Just after its launching, WeChat was already developing add-ons to make it more different than just a messaging app. It is the Chinese version of Twitter because it also has the so called WeChat Moments. Here the users can post short messages and pictures or videos and their followers can like it, can comment and can share it to others. It kept developing that much that it was the first messaging application to add phone and video calls. Introduced the funny stickers (animated Gif’s) and be able to share your location through GPS.
If WeChat was already a great application the best came during the 2014’s Chinese New Year. Here was the moment where the game changer was settled. In China is a tradition to give hongbaos, red envelopes, with money in it to the relatives and employees. So WeChat made possible to link users credit cards to the app and create a digital red envelope. That year already 20 millions of digital hongbaos were given. This and the feeling of security that Chinese users have regarding digital payments make possible to start buying everything scanning QR codes using WeChat or Alipay.
Nowadays, in China all kind of shops have a QR code placed at the counter for customers to scan. Is that popular that even some beggars in the street have a QR code to get some money in case people told them they are runout of coins. Another example of great service is the splitting the bill option. When a group of friends go for dinner and the check comes, one of them pays the total amount and then if all them are in a WeChat group it possible to split the bill in it. One by one, they will pay their share and at the end all the money will be deposited in the payer WeChat account.

Other functions of WeChat, mostly included inside the digital wallet is that users able to pay all the house utilities bills (gas, water, electricity), mobile top up. These services are powered by Tencent, but other services included are powered by third-party operators. Here users can order a taxi through Didi company (Chinese Uber), purchase train and flight tickets through ELong, order food delivery provided by Meituan company, use the bike sharing Mobike, and buy cinema tickets.
Another Tencent main assets are online games, with Wángzhě Róngyào(Arena of Valor) as their flagship game. This multiplayer online battle arena has more than 80 million daily players. As you can imagine, this community use WeChat to get connected.

His main competitor is Alipay, a third-party mobile and online payment platform. It belongs to Alibaba group, the company founded by Jack Ma, but its parent company is Ant Financial. Alipay or Zhīfùbǎoin Chinese, was launched for first time in 2004 as an online payment for buyers using Taobao website, the equivalent of Amazon in China and also part of Alipay. It was design to be the substitute of Paypal. Nowadays Alipay is the most used mobile and online payment platform with 5.2 billion users and making a revenue of 250.3 billion yuan and making a net income of 61.41 billion yuan.
Alipay can be used like WeChat to buy almost everything. Also there are third-party operators that provides the same services but except for Didi, Alipay has their own collaborators: To buy movies uses Taopiao, to purchase air and train tickets uses Flying Pig, the bike sharing companies are OFO and Hellobike, to order food delivery uses Eleme.
One big difference between WeChat wallet and Alipay is that on the Tencent platform users, once linked their credit card, they need to top up in order to have a deposit, then all the purchases or collections will be summed or deducted from it. However, Alipay, even having this deposit wallet, all transactions will be deducted from buyers bank account in real-time.
Sellers have incorporated both systems as a payment method so right now the use of credit cards and cash has decreased a lot. Great plus of Alipay is that all purchases online are free of service fees. WeChat charges a 0.1 % on credit cards repayment amounts.
From my point of view it is hard to say which one is best because I use both, every day. However I prefer to use WeChat to purchase simple things, and use Alipay for more serious transactions, like paying the rent.