Buiding multiple site from the same 11ty repo is not obvious, but also not hard. This template demonstrates the key features.
The eleventy.config.js starts by looking for an env variable named SITE, this will be used for configuration of 11ty and plugins. Ultimately this is just a drictory name under ./sites that is used to compute the input directory. In this example I also specify an output directory, which might be nessisary if your CI/CD system has a shared cache by repo.
Template Litterals are used to inject the input path into addPassthroughCopy() and similar functions.
Finally, the input and output directories are stored as global data since some plugins require this at the template level, rather than reading in from eleventyConfig.dir.
- Site 1
SITE=site-1 npx @11ty/eleventy - Site 1
SITE=site-2 npx @11ty/eleventy
- Site 1
SITE=site-1 npx @11ty/eleventy --serve --quiet - Site 2
SITE=site-1 npx @11ty/eleventy --serve --quiet
Hosts like Netlify support multiple targets from the same repo, just make sure to set the correct env variable and publish directory for each Build & Deploy.