Does "posthaste" mean something like "ASAP"? And is it usually put at the end of sentence?

Native speaker’s answer
Rebecca
Yes, "posthaste" is similar to "ASAP" or "as soon as possible" as it means as fast as one can, or with all possible speed. As an adverb, it is usually put at the end of a sentence to express time. Ex: Can you send the invitations out posthaste? Ex: We need to warn the others, posthaste. = We need to warn the others ASAP.