6.1.0 • Public • Published


Synchronizes selected NPM packages from a remote NPM registry (such as to a local folder. The local copy can then be used as a simple private NPM registry without publishing capabilities. Pre-built native binaries bundled with node-pre-gyp are also included.

npm version Run tests


  • Node.js v18.20.0 or newer


npm install -g registry-sync


Synchronizing packages from the registry

registry-sync [options]

-h, --help               output usage information
-V, --version            output the version number
--root <path>            Path to save NPM package tarballs and metadata to
--manifest <file>        Path to a package-lock.json or yarn.lock file to use as catalog for mirrored NPM packages
--localUrl <url>         URL to use as root in stored package metadata (i.e. where folder defined as --root will be exposed at)
--binaryAbi <list>       Optional comma-separated list of node C++ ABI numbers (NODE_MODULE_VERSION) to download pre-built binaries for.
                         Look for NODE_MODULE_VERSION in release ChangeLogs via
                         Default value is from the current Node.js process.
--binaryArch <list>      Optional comma-separated list of CPU architectures to download pre-built binaries for.
                         Valid values: arm, arm64, ia32, and x64.
                         Default value is from the current Node.js process.
--binaryPlatform <list>  Optional comma-separated list of OS platforms to download pre-built binaries for.
                         Valid values: linux, darwin, win32, sunos, freebsd, openbsd, and aix.
                         Default value is from the current Node.js process.
--registryUrl [url]      Optional URL to use as NPM registry when fetching packages.
                         Default value is
--registryToken [string] Optional Bearer token for the registry.
                         Not included by default.
--dontEnforceHttps       Disable the default behavior of downloading tarballs over HTTPS (will use whichever protocol is defined in the registry metadata)
--includeDev             Include also packages found from devDependencies section of the --manifest.
                         Not included by default.
--dryRun                 Print packages that would be downloaded but do not download them


registry-sync --root ./local-registry \
  --manifest ./package-lock.json \
  --localUrl http://localhost:8000 \
  --binaryAbi 93,108 \
  --binaryArch x64,arm64 \
  --binaryPlatform darwin,linux

Re-executing registry-sync will only download and update files for new package versions.

Serving the local root folder after synchronization

Configure a web server to use index.json as index file name instead of index.html. Also configure HTTP 404 responses to have an application/json body of {}.

For example, for local testing you can run nginx in a container to serve the downloaded packages:

# Create a very simple nginx config
cat <<EOF >nginx.conf
server {
  listen 8000;
  server_name localhost;

  location / {
    root /usr/share/nginx/html;
    index index.json;

  error_page 404 @404_empty_json;

  location @404_empty_json {
    default_type application/json;
    return 404 '{}';

# Run nginx and serve directory local-registry
docker run --rm --name registry -p 8000:8000 \
  --volume="${PWD}/local-registry:/usr/share/nginx/html:ro" \
  --volume="${PWD}/nginx.conf:/etc/nginx/conf.d/default.conf:ro" nginx:1.19

Then you can install dependencies from the local registry using npm

npm_config_registry='http://localhost:8000' npm install

or using yarn

YARN_REGISTRY='http://localhost:8000' yarn install

Creating a separate lockfile for synchronization

In some cases npm might not include all optional packages that are needed for all platforms to package-lock.json, depending on which OS you used to create the lockfile.

In this case it might be useful to copy the package.json that you want to synchronize as a local repository to somewhere else and create a new cross platform package-lock.json by running:

npm install --force --package-lock-only

After this you can pass the new lockfile to registry-sync.


See releases.


Pull requests are welcome. Kindly check that your code passes ESLint checks by running npm run eslint:check first. Integration tests can be run with npm test. Both are anyway run automatically by GitHub Actions.

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npm i registry-sync

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  • heikkipora