How to fix npm ERR! code EAUTHTOKEN npm ERR! Authentication token is invalid or expired in npm

First check if npm recognizes your current authentication status.

npm whoami

If this command returns 'not logged in' or throws an error, you need to authenticate. If it returns a username, your local token exists but may be expired or invalid for the registry you're trying to access.

Remove your current .npmrc file and re-authenticate. This generates a fresh token.

On macOS/Linux:

rm ~/.npmrc
npm login

On Windows:

del %USERPROFILE%\.npmrc
npm login

You'll be prompted for username, password, and email. npm will automatically create a new .npmrc with a valid token. This is the most straightforward fix for local development.

If you use a private registry (GitHub Packages, GitLab, Azure Artifacts, etc.), you need to generate a new token from that service, not npm.

GitHub Packages:
1. Go to https://github.com/settings/tokens
2. Click "Generate new token (classic)" or "Generate new token (fine-grained)"
3. Select scopes: read:packages and write:packages
4. Copy the token and update your .npmrc with the new token

GitLab:
1. Go to https://gitlab.com/-/user_settings/personal_access_tokens
2. Create a new token with read_api and write_repository scopes
3. Update your .npmrc with the new token

Generic .npmrc Update:

npm config set //registry.example.com/:_authToken "YOUR_NEW_TOKEN_HERE"

Stale cache or corrupted package-lock.json can cause persistent authentication issues. Do a clean reinstall.

On macOS/Linux:

rm -rf node_modules
rm -f package-lock.json
npm cache clean --force
npm install

On Windows:

rd /s /q "node_modules"
del package-lock.json
npm cache clean --force
npm install

This forces npm to re-authenticate and fetch fresh package data from the registry.

Never commit tokens to git. Instead, use environment variables in CI/CD pipelines.

Create a .npmrc at the project root (do not commit this file):

//registry.npmjs.org/:_authToken=${NPM_TOKEN}
@yourscope:registry=https://registry.example.com/
//registry.example.com/:_authToken=${YOUR_PRIVATE_TOKEN}

Then in your CI/CD pipeline, set the environment variable:

GitHub Actions:

steps:
  - name: Install dependencies
    run: npm install
    env:
      NPM_TOKEN: ${{ secrets.NPM_TOKEN }}
      YOUR_PRIVATE_TOKEN: ${{ secrets.PRIVATE_REGISTRY_TOKEN }}

GitLab CI:

install:
  script:
    - npm install
  variables:
    NPM_TOKEN: $NPM_TOKEN