The built-in bulk coupon tool stops at 1,000 codes, and getting each customer their own code is up to you. Coupon Forge lets you describe the discount once and create the whole set: percent off, a fixed amount or free shipping, for store products, bookings or event tickets, with limits and dates. Up to 10,000 unique codes per set, without look-alike characters such as 0, O, 1 and I.
Then send them. Pick a set and a contact label, and each contact who agreed to marketing emails gets their own unused code. The app records who got which code, so a second run only reaches people who have none yet. A table shows email, code, send time and whether the code was redeemed, and exports to CSV. Each email counts toward your site's monthly email limit, which the app shows before you send. The free plan sends 10 a month.
Your sets show how many codes were used. Export one to CSV, delete it when the campaign ends, or import codes you already have.
Everything runs inside your dashboard with no outside servers. The list of sent codes is stored in a collection on your own site.