Nutrient Packed Morsels


    0.3.2 • Public • Published


    A lazy mirroring local npm server.

    Build Status


    This package provides a lazy mirroring option for those that:

    • Don't want to mirror the entire couchDB for
    • Don't want to setup cron jobs for those tasks
    • Want to use an in-memory caching server (allocation configurable)
    • Want to easily cache dist tarballs and package metadata to disk


    • npm install -g npm-lazy-mirror


    With CLI flags:

    • npm-lazy-mirror -p <port> -a <remote_address> -b <bind_address> --cache-dir /npm-data

    With a JSON configuration:

    • npm-lazy-mirror -C /path/to/config,json

    See example/server-config.json for usage.

    Note: Your remote_address configuration is important, as it is the address used when re-writing tarball URLs in the metadata. It's certainly always best to use a DNS entry here, rather than an IP.

    Client configuration

    Simply point your local npm config to the lazy mirror (permanent):

    npm config set registry http://localhost:2000/

    or per install:

    npm i --registry http://localhost:2000 supertest


    Run npm-lazy-mirror -h to see a full list of options.


    • Caches all tarball / JSON metadata to disk
    • Mirror serves files (200MB max by default) from memory, with a configurable LRU cache.
    • Ability to blacklist packages by semantic versioning specification
    • Option to serve stale resources while the upstream registry is offline
    • Upstream resources are fetched on the fly from the remote registry, the fetching, storing and serving to the client all happen in the same request.
    • Configurable with custom npm registries.
    • HTTP/S proxy support
    • It's Fast and stands up under load. Expect 5000+ req/s with one core.

    A cold run installing express takes ~12 seconds (fetching from upstream registry on-the-fly):

    npm install express  2.44s user 0.81s system 27% cpu 11.769 total

    A warm run after all express assets are locally cached takes ~3 seconds:

    npm install express  2.43s user 0.78s system 115% cpu 2.768 total

    Implementation Caveats

    You cannot use this mirror for publishing modules or user management, such requests will be forwarded to the upstream registry for processing.


    npm i npm-lazy-mirror

    DownloadsWeekly Downloads






    Last publish


    • jamiep
    • activestate