To ensure the integrity of packages you download from the public npm registry, or any registry that supports signatures, you can verify the registry signatures of downloaded packages using the npm CLI.

Prerequisites

  1. Install npm CLI version v8.15.0 or later
  2. Install dependencies using npm install or npm ci

Verifying registry signatures

Registry signatures can be verified using the following audit command:

npm audit signatures

Example response if all installed versions have valid registry signatures:

audited 1640 packages in 2s
1640 have verified registry signatures

Troubleshooting

Some packages are missing registry signatures

The CLI will error if packages don't have signatures and if the package registry supports signatures. This could mean an attacker might be trying to circumvent signature verification. You can check if the registry supports signatures by requesting the public signing keys from registry-host.tld/-/npm/v1/keys.

Example response if some versions have missing registry signatures:

audited 1640 packages in 2s
1405 packages have verified registry signatures
235 packages have missing registry signatures but the registry is providing signing keys:
missing-dep@1.0.0 (https://registry.npmjs.org/)
...