Which is funny, StoryGraph is a Ruby on Rails app, exposing an API is a doable thing, which leads me to believe it is not a priority or a purposeful design decision.

It is on the long-term roadmap https://roadmap.thestorygraph.com/features/posts/an-api

Yeah Hardcover seems to have a GraphQL API they use for their UI, which they expose. There’s not a lot of extra polish for third party devs — it feels like “this is the API we use, use it or not, things may break”. On the other hand, StoryGraph does server-side rendering and so it doesn’t have an API already. So adding one would be a decent amount of work

To be clear, Hardcover also does server-side rendering.

GR ditching their API was one of the primary motivations for Adam Fortuna (Hardcover's founder and Lead Dev) to even think about trying to create a competitor, so when he did create one, having an API available to others was a primary focus.

Note: Hardcover is also working towards open sourcing at some level, hopefully in 2025.

I’m going to guess most of their users aren’t asking for an API

Right now we get a lot of tech/ dev oriented users, and many of those are looking for an API :)