The government of Canada has issued up-to-date guidance on when to register for GST/HST.
According to current regulations, you need to register and account for GST/HST if you make taxable sales (or other relevant supplies) in Canada and you are not a small supplier.
A small supplier, under Canadian regulations, is with a revenue of no more than CA$30 000 (for most businesses).
Small suppliers do not have to register for GST/HST, but can choose to do so voluntarily.
Source VATglobal
