API
This site is hosted on GitHub pages, so as long as GitHub supports CORS, the API should support it too.
Services
Service's data are available as JSON. You can access them by replacing .html with .json in URL.
Example
$ curl https://oniontree.org/services/nytimes.json
PGP keys
You can download PGP keys, if you know their ID.
Example
$ curl https://oniontree.org/keys/E9971784146CCD94.txt