noun
Common loanword used in digital communication (email, social media, messaging) and general contexts for a reply or response.
メールのリプライがまだ来ていない。
I haven't received a reply to my email yet.
彼のツイートにリプライを送った。
I sent a reply to his tweet.
返信 is a native Japanese word also meaning 'reply', often used for email or formal correspondence. リプライ is a more casual loanword, especially common in social media and online contexts.
返事 is a general term for 'reply' or 'answer', used in both spoken and written communication. リプライ is more specific to written digital replies.
Borrowed from English 'reply'.