noun
prompt reply; immediate response
Used for a quick reply, especially in digital communication such as email or messaging.
メールの即返信ありがとうございます。
Thank you for your prompt reply to my email.
彼はいつも即返信をくれる。
He always gives me an immediate response.
即レス is a more casual, slangy abbreviation for 'instant reply', often used in chat contexts.
Compound of 即 (そく, 'immediate') and 返信 (へんしん, 'reply').