WeChat etiquette with Chinese suppliers
Most Chinese suppliers run day-to-day business on WeChat: add the contact after a first meeting, keep each message to one question, expect quick but informal replies and voice notes, and confirm prices, specifications and payment details by email or proforma afterwards, because chat is easy to lose.

Adding and introducing yourself
After a first meeting or email, a supplier will usually suggest WeChat. Add them with a short message saying who you are and which company you represent, and use your real name and business details on your profile. A clear first message avoids being mistaken for a spam request.
Keep personal and business chat separate where you can. Many buyers use a business WeChat account for suppliers rather than their private one.
Messages, voice notes and response times
Keep each message to one question, and number several questions rather than writing a paragraph. Voice notes are common in China: you can reply by text, and a translation app can read a voice note if you need it. Replies are often quick during Chinese working hours and slow outside them, so allow for the time difference.
Do not assume a quick informal "OK" settles an agreement. It may simply be a courtesy. Ask for a short written confirmation of the point so both sides have a clear record of what was agreed.
What must still be in writing
Chat is where you ask and clarify. Prices, specifications, quantities, delivery dates and payment details should be confirmed in a proforma invoice, a purchase order or an email that both sides can file, because chat history is easy to lose and hard to use later. Send a short summary after each important conversation and ask them to reply "confirmed".
Check payment details on the invoice, not only in chat, and ask for the company name, bank and account number in writing. See the payee checks.
Groups and holidays
Suppliers sometimes add you to a group with their sales, production and shipping staff. That is useful, but keep the group on topic and move any commercial agreement back to email. Messages around Chinese public holidays may go unanswered for days: check the China holiday calendar before you expect a reply.
For the wider picture, see the etiquette guide and the copy-paste Chinese messages.
Frequently asked questions
Do Chinese suppliers use email or WeChat?
Most use WeChat for day-to-day messages and email for formal documents. Use chat to ask and clarify, and email or a proforma to confirm anything binding.
Is a WeChat message a contract?
Treat it as a record of a conversation, not as the agreement. Confirm prices, specifications, quantities and payment details in a proforma, a purchase order or an email.
Why does a supplier not reply on WeChat for days?
It may be a Chinese public holiday or the time difference. Check the holiday calendar, and send a short follow-up with a single question.