The best ways to filter quality suppliers are:
1) Attending exhibitions and sourcing fairs;
2) Using some b2b websites, but you need to verified the qualification of your negotiating suppliers. You need ask supplier send emails via their official domain account.
Some tools to examine supplier:
a. Find IP address from your supplier's email and check it on
www.whatismyipaddress.com to locate your supplier.
b. Search your supplier's domain on
www.whois-search.com or
www.hostsearch.cc to check the domain register information.
c. Maybe this criterion is most important. check carefully your supplier's website, if they can offer many kinds of products, then the company is a
trade company.
d. Query supplier's website whether has had ICP(Internet Content Provider) legally recorded.
Go to
http://www.miibeian.gov.cn/CX/main.jsp and click the left knock-down "公共信息查询", then type domain name(without http:// or
www.) of the website into the second textbox, then click "查询" button. Then list show if website has recorded, and you will need click on the right most link "浏览" for details.
Then check whether the register name just as the website stated(most register names can be find identical as "contact" on the website shows).