Your codes can contain prefixes, suffixes, random blocks, as well as any other characters as separators.
Random blocks use the following formats: [?LN], [?L], [?N], where ? can be replaced with any number you want.
For example, the pattern [8LN] will generate 8 random letters and numbers, such as HW2CD9JC.
The pattern [10N] will generate 10 random numbers, such as 2273497742.
The pattern [5L] will generate 5 random letters, such as HFRNM.
Aside from random blocks, you can also add other words, or character blocks that you want to be non-random (present in all codes).
For example, lets' say you want to generate a set of 20,000 unique codes that offer 10% off all your products for a Black Friday promo - you could use a pattern such as: BLACKFRIDAY-[8LN]-10OFF
The codes that would be generated from the pattern BLACKFRIDAY-[8LN]-10OFF would all share the prefix BLACKFRIDAY and the suffix 10OFF, with 8 random letters and numbers sandwiched in between.
e.g.
BLACKFRIDAY-HTD8JHD4-10OFF
BLACKFRIDAY-PQGV5HN8-10OFF
BLACKFRIDAY-542D4PW6-10OFF
BLACKFRIDAY-6NTLT35G-10OFF
BLACKFRIDAY-JTJF6S97-10OFF
...
To make sure your pattern is correct and the codes being generated will actually look how you want them to look like, it can be a good idea to keep an eye on the Preview in the right side-bar and click on See another to see more code examples.
Important Note #1
Please make sure you use enough random letters and/or numbers in your code to cover the total codes you want to generate. For example, if you want to generate 1,000,000 codes using a pattern such as [2LN] will be insufficient because there are only about 900 unique codes which can be generated from that pattern.
If you're unsure what pattern to use, here are our recommendations:
Up to 100,000 codes: [8LN] (or variations such as BF-[8LN] or [8LN]-15OFF)
Up to 1,000,000 codes: [10LN] (or variations such as BF-[10LN] or [10LN]-15OFF)
Up to 20,000,000 codes: [12LN] (or variations such as BF-[12LN] or [12LN]-15OFF)
Important Note #2
While Shopify allows you to use spaces and other special characters in your codes, we recommend limiting yourself to uppercase letters, numbers and dashes to avoid confusing your customers.