Welcome to e-Invoice System. From 01-01-2021, e-invoicing mandatory for taxpayers with aggregate turnover more than Rs. 100 Cr. e-Invoice APIs enabled on Trial sites for taxpayers with PAN based turnover more than Rs. 100 Cr. in a financial year (https://einvoice1-trial.nic.in/, https://einv-apisandbox.nic.in/). Taxpayers having TO more than Rs. 500 Crores but not enabled for e-invoicing can register voluntarily using option Registration -> e-Invoice Enablement in the portal. API Sandbox tool has been enabled for ERPs and e-Commerce operators. Click on https://einv-apisandbox.nic.in/einvapiclient/EncDesc/Registration.aspx for registration.