Libraries.io website, libraries.io, open-source package search, package metadata, dependency data, package managers, API access, GitHub repositories, npm, PyPI, Maven, NuGet, and WHOIS domain data

Libraries.io

Libraries.io is a website for discovering open-source packages and package metadata across many package managers, with search, dependency information, repository links, and API access.

Core purpose

Libraries.io collects public open-source package information so users can search packages, compare metadata, inspect dependencies, and explore package ecosystems.

Official domain

libraries.io is the official website for package search, package manager coverage, API documentation, and open-source dependency metadata.

Domain created

September 30, 2014

The Libraries.io site logo used as the brand image for the website page.View official Libraries.io logo

What Libraries.io is

Libraries.io official site describes Libraries.io as a service that collects publicly available open-source package information from the internet. The site lets users search packages by license, language, popularity, package manager, dependency relationships, and repository metadata. Libraries.io is useful because open-source software is spread across many ecosystems. A developer may need to compare packages from npm, PyPI, Maven, NuGet, RubyGems, Packagist, Cargo, and other package managers without opening every registry one by one.

Package and ecosystem search

The website indexes package metadata from many package managers and links packages to repositories where possible. Users can search for packages, inspect versions and releases, review declared licenses, look at dependent projects, and compare activity signals that help with early package evaluation.

Dependency and repository context

Libraries.io connects package pages with source repositories, dependency lists, release information, and package-manager metadata. That context can help users understand whether a package is actively maintained, widely used, connected to a known repository, or part of a larger dependency graph.

API access

Libraries.io offers API access for registered users. Its API documentation describes authentication with an API key, rate limits, pagination, and endpoints for platforms, projects, repositories, dependencies, and search. That makes the site useful not only in a browser but also inside tooling and data workflows.

Data limits and accuracy

Libraries.io states that its data is scraped from public sources and is not validated, corrected, or curated for accuracy in the same way as paid curated data offerings. That warning matters: the site is helpful for discovery and signals, but important open-source governance decisions still need additional review.

Who uses Libraries.io

Libraries.io is used by developers, open-source maintainers, package researchers, DevOps teams, security analysts, dependency-management tool builders, engineering managers, and people comparing package ecosystems. Some users search for libraries manually, while others use the API to analyze dependency and package metadata at scale.

Why it matters

Libraries.io matters because package choice is rarely only about a name or download count. Developers need metadata, licenses, repository links, dependency context, and ecosystem coverage to make better decisions. A cross-registry index gives them a broader view than any single package manager can provide on its own.

WHOIS domain data

Data pulled: May 24, 2026View current WHOIS record

Domain: libraries.io
IP address: 35.244.128.241
Registrar: Gandi SAS
WHOIS server: whois.gandi.net
Referral URL: https://www.gandi.net
Created: September 30, 2014
Updated: November 26, 2025
Expires: September 30, 2026
Nameservers: ns-cloud-b1.googledomains.com (216.239.32.107); ns-cloud-b2.googledomains.com (216.239.34.107); ns-cloud-b3.googledomains.com (216.239.36.107); ns-cloud-b4.googledomains.com (216.239.38.107)
Domain status: clientTransferProhibited
Contact privacy: Registrant name and contact details are redacted for privacy; registrant organization is listed as SonarSource Sàrl, and admin and technical contact details are redacted.

Key concepts

Package managerA registry or ecosystem such as npm, PyPI, Maven, NuGet, RubyGems, or Packagist.
Package metadataPublic information such as versions, licenses, languages, repository links, releases, and dependencies.
Dependency graphA network of packages that rely on one another directly or indirectly.
API keyA token used to authenticate API requests to Libraries.io.

Common workflows

Search for packages across multiple package managers from one website.
Review license, language, release, dependency, and repository metadata before choosing a package.
Use API endpoints to collect package, platform, repository, and dependency data for internal tools.
Compare package ecosystems when evaluating open-source technology choices.

Common misconceptions

Libraries.io is not a package registry; it indexes and links package information from other package managers.
Libraries.io data can be helpful without being authoritative; important decisions still need source registry and repository checks.
A package appearing on Libraries.io does not mean it is secure, maintained, or suitable for production use.

Open questions

How should cross-registry indexes present trust, maintenance, and security signals without implying more certainty than the data supports?
How will package metadata quality improve as ecosystems standardize provenance, deprecation, and maintainer signals?
How should teams combine public package metadata with private dependency inventories and policy requirements?