Stallion is a headless CMS built atop Svelte and Sapper.
The following is a bunch of rambled thoughts that I wanted to make sure to record and not forget, but I'll come back to later and better organize.
Stallion uses rollup-plugin-replace for environment variable replacement. Any environment variable prefixed with STALLION_ will automatically be replaced in the code if it's listed as a process.env.* variable. For example:
process.env.STALLION_ARANGODB_CONNECTION
Is replaced with with the connection string.
process.env.NODE_ENV and process.env.PORT are the only non-prefixed variables to also be replaced.