Generating unique, hard-to-guess “coupon” codes

Question

My Rails app needs to generate electronic coupons for users. Each coupon given should have a unique coupon code that can be redeemed on our system.

For example a cou

Answer 1

Get an epoch timestamp and base encode it.. as long as you save a record of it somewhere you can compare if it's valid when it's used.

If you need it to be enterable by hand you can always .string() it down to first 8 or so characters.