X sends an offer to Y by E-MAIL, and Y accepts by e-mail. The parties communicate through an instantaneous medium. Under the Indian Contract Act, 1872, the acceptance and the completion of the contract:

For INSTANTANEOUS modes of communication (telephone, telex, e-mail, fax), the acceptance is complete as against the acceptor when the acceptance is posted, but the contract is regarded as complete against the offeror only when the acceptance is RECEIVED - the mailbox/postal rule (which applies to letters) does not extend to instantaneous communication. This is the settled position from the leading English decision and its Indian application to modern media. Where a reply is expected, a delay in receipt does not bind the offeror until received. This makes the receipt rule the operative test for e-commerce contracts.