CSV Coupon Importer
Easy Digital Downloads has a very nice interface for creating Discount Codes, but entering many of them at once can be time consuming. Fortunately the CSV Coupon Importer allows you to import many of them at once from a CSV file.
The first step is to map your CSV columns to Discount Code values. This is done under Downloads → Settings → Extensions → Coupon Importer.
Find the section titled CSV Coupon Import Mapping and for each Discount Code value choose the column that matches.
Here's an example of a CSV file in a spreadsheet application:
Here's the mapping interface to match that CSV data:
Each field will tell you what kind of data needs to be there, whether it's a specific word like "flat" or a boolean like 0 or 1.
When you've finished mapping the values, click Save Changes at the bottom of the page.
Once your columns are mapped properly go to Downloads → Import Coupons. There you may choose your input file.
Before committing to the import you may choose Validate File Only.
This will check your file for problems, so that you can fix them before actually importing.
Once your file has validated you can choose Import File with the validator checkbox unchecked and your coupons will import.
It's possible to try to import so many items at once that your server will time out. Each server has a different timeout setting, you'll need to experiment with yours.
When it times out it will have successfully imported a number of discount codes, so you should check to see how many worked.