We are excited to present our Coupon Codes Import for Magento 2, full of great features.
The extension allows importing any number of coupon codes at once. Support import via plain-text/text-area, CSV and TXT files. Comes with a sample CSV/TXT import file and display detailed import messages (failed, duplicates and success) during the import.
Feel free to read through the Coupon Codes Import product page for more details and try out the live demos version.