composer config -g repo.packagist composer https://mirrors.mamad.dev/packagist/YOUR_KEY
{
"repositories": [
{"type": "composer", "url": "https://mirrors.mamad.dev/packagist/YOUR_KEY"}
]
}Proxies repo.packagist.org. Metadata URLs are rewritten so Composer fetches package info through the mirror. Actual package downloads go to their source (GitHub, etc.). Cached for 7 days.