ecosyste.ms Packages API

Base URL: https://packages.ecosyste.ms/api/v1

All responses are JSON. No auth required. Set a User-Agent header identifying yourself. Unauthenticated clients share a rate limit and may see 429.

Full OpenAPI spec: https://packages.ecosyste.ms/docs/api/v1/openapi.yaml

Look up a package

By ecosystem + name, repository URL, or purl. Returns an array (the same name can exist in many ecosystems).

curl -s 'https://packages.ecosyste.ms/api/v1/packages/lookup?ecosystem=pypi&name=numpy'
curl -s 'https://packages.ecosyste.ms/api/v1/packages/lookup?purl=pkg:npm/lodash'
curl -s 'https://packages.ecosyste.ms/api/v1/packages/lookup?repository_url=https://github.com/numpy/numpy'

Bulk lookup (POST, up to 1000 at once):

curl -s -X POST 'https://packages.ecosyste.ms/api/v1/packages/bulk_lookup' \
  -H 'Content-Type: application/json' \
  -d '{"purls": ["pkg:npm/lodash", "pkg:pypi/requests"]}'

Fetch from a specific registry

Registry names are hostnames: npmjs.org, pypi.org, rubygems.org, crates.io, proxy.golang.org, repo1.maven.org, nuget.org, packagist.org, hub.docker.com, cocoapods.org, pub.dev. List all with GET /registries.

Package names containing / must be URL-encoded (%2F).

curl -s 'https://packages.ecosyste.ms/api/v1/registries/npmjs.org/packages/lodash'
curl -s 'https://packages.ecosyste.ms/api/v1/registries/rubygems.org/packages/rails'
curl -s 'https://packages.ecosyste.ms/api/v1/registries/proxy.golang.org/packages/github.com%2Fstretchr%2Ftestify'

Useful fields in the response: latest_release_number, latest_release_published_at, first_release_published_at, versions_count, dependent_packages_count, dependent_repos_count, docker_dependents_count, docker_downloads_count, downloads, rankings, maintainers, repo_metadata, advisories, funding_links, status. The response also includes follow-up URLs: dependent_packages_url, usage_url (repos service), docker_usage_url (docker service).

Versions

# all versions (paginated, newest first)
curl -s 'https://packages.ecosyste.ms/api/v1/registries/npmjs.org/packages/express/versions'

# just the version number strings
curl -s 'https://packages.ecosyste.ms/api/v1/registries/npmjs.org/packages/express/version_numbers'

# a single version with its declared dependencies
curl -s 'https://packages.ecosyste.ms/api/v1/registries/npmjs.org/packages/express/versions/4.19.2'

# latest only
curl -s 'https://packages.ecosyste.ms/api/v1/registries/npmjs.org/packages/express/latest_version'

Dependent packages

Other packages on the same registry that declare this one as a dependency. Sortable by downloads, dependent_repos_count, dependent_packages_count, latest_release_published_at etc, so you can find the most significant downstream consumers first.

# top dependents by download count
curl -s 'https://packages.ecosyste.ms/api/v1/registries/npmjs.org/packages/lodash/dependent_packages?sort=downloads&order=desc&per_page=20'

# breakdown of dependent kinds (runtime, dev, peer)
curl -s 'https://packages.ecosyste.ms/api/v1/registries/npmjs.org/packages/lodash/dependent_package_kinds'

# packages often used alongside this one
curl -s 'https://packages.ecosyste.ms/api/v1/registries/npmjs.org/packages/lodash/related_packages'

Usage footprint across the ecosystem

The package response gives you counts (dependent_packages_count, dependent_repos_count, docker_dependents_count, docker_downloads_count). For the actual lists, follow up on the other services. The ecosystem name in these URLs is the package manager (npm, pypi, cargo, bundler, go, maven), not the registry hostname.

# repositories that depend on it (repos service)
curl -s 'https://repos.ecosyste.ms/api/v1/usage/npm/lodash/dependent_repositories?sort=stargazers_count&order=desc'

# docker images that ship it (docker service)
curl -s 'https://docker.ecosyste.ms/api/v1/usage/npm/lodash'

Together these three views (dependent packages, dependent repos, docker images) give a rounded picture of a package's blast radius.

Maintainers and namespaces

curl -s 'https://packages.ecosyste.ms/api/v1/registries/npmjs.org/maintainers/sindresorhus'
curl -s 'https://packages.ecosyste.ms/api/v1/registries/npmjs.org/maintainers/sindresorhus/packages'
curl -s 'https://packages.ecosyste.ms/api/v1/registries/npmjs.org/namespaces/@babel/packages'

Keywords and critical packages

curl -s 'https://packages.ecosyste.ms/api/v1/keywords/http'
curl -s 'https://packages.ecosyste.ms/api/v1/critical?registry=pypi.org'
curl -s 'https://packages.ecosyste.ms/api/v1/critical/sole_maintainers?registry=npmjs.org'

Pagination and sorting

List endpoints accept ?page=N&per_page=N (max 1000). Sortable endpoints accept sort (e.g. downloads, dependent_repos_count, latest_release_published_at) and order (asc/desc).

When to use

• The user asks about a package on any registry
• Checking adoption, release cadence, or maintainer count for a library
• Finding what depends on a package and how widely it's deployed (registry, repos, docker)
• Estimating the blast radius of a vulnerability or breaking change
• Listing every package an org or maintainer publishes
• Resolving a purl to its registry metadata