How to fix npm ERR! code E503 npm ERR! 503 Service Unavailable - registry temporarily unavailable in npm

First, verify whether npm's infrastructure is experiencing an outage.

Visit https://status.npmjs.org in your browser to check for any reported incidents. If there's an active outage, the best action is to wait for npm's team to resolve it.

Check which registry your npm client is using:

npm config get registry

The output should be https://registry.npmjs.org/. If it shows a different URL, that registry may be down.

Reset to the official npm registry:

npm config set registry https://registry.npmjs.org/

Ensure your internet connection is working:

ping google.com
dig registry.npmjs.org

If DNS lookup fails, try using a different DNS server (e.g., Google's 8.8.8.8).

Corrupted cache can sometimes cause connectivity errors:

npm cache clean --force
npm install

If you're on a corporate network with a proxy:

npm config set proxy http://user:[email protected]:8080
npm config set https-proxy http://user:[email protected]:8080

To remove proxy settings:

npm config rm proxy
npm config rm https-proxy

As a temporary workaround while npm is down:

npm --registry https://registry.npmmirror.com install

Then switch back:

npm config set registry https://registry.npmjs.org/