Is sales tax ID same as Ein?

We need to open up the question to properly be able to answer it.

What is an EIN (Employer Identification Number)?

For Canadians the best way to understand EIN is to compare it to the BN (business number). The general purpose and uses of EIN in USA is similar to the BN here in Canada. 

EIN is issued by IRS at the federal level to identify businesses, especially when filing taxes. Similar to BN in Canada, EIN can be registered for any type of business (Sole Proprietorship, Partnerships, Corporations etc.)

Sales tax ID in US

Sales taxes in the US (such as GST) are managed at the state level and not the federal level. As we noted above EIN is a federal level tax ID. The registration for sales tax also occurs at the state level. This means that the Sales tax ID is issued at the state level and they will determine what number will be used to identify your business for GST purposes in that state.

eCommerce sellers in Canada are obligated legally to register and remit sales taxes given certain criteria being met. Contact a professional accountant for more information.