🔗 Hosting PR previews on GitHub Pages for free

GitHub Pages offers a free way to host static websites, usually at a single URL per repository. However, it presents challenges when trying to preview pull requests (PRs). Instead of relying on third-party services for PR previews, I discovered a workaround by hosting them within the main GitHub Pages site under subdirectories named after the PR numbers.

When a PR is opened, a GitHub Actions workflow automates the deployment of the site to a URL like https://<username>.github.io/<repository>/previews/pr-123/. This method allows for quick previews, albeit with caveats such as managing relative asset paths and updating the robots.txt file to prevent indexing. I implemented two workflows: one for deploying PR previews upon opening or updating a PR and another for deploying the main site when changes are merged. This approach streamlines my process without relying on external services.