Like most sites, there are public and "private" APIs. Publicly documented APIs are officially support. Private API can (and often do) change at any time, which is why we don't recommend they be consumed by customers.
I don't understand.. Why wouldn't they spend the few minutes needed to just make this public?
It's not the cost of making the API public that's the burden, it's the cost of supporting the API.
They SHOULD have it released, no dispute about it, but it probably will take more than a few minutes, particularly for a platform their size. Between testing/validation and documentation it is not unreasonable to suspect that they simply haven't gotten to it.
Still, as noted in the article this was "one of the most request features" 2 years ago.
Hi, Shopify dev here - when we roll out APIs we usually keep them private for a period before making them public to iron out bugs as well as harden them to work fast at scale.
Awesome to see this post, and your response here... I'm actually the author of the article.. Can you be more specific than "period"? It seems you guys have had coupon generation ability for quite some time.
BTW, if you're interested, http://www.shopify.com/careers - things like "I reverse engineered your private APIs and got it on front page of HN" set you apart from the herd ;)