semver.io

A webservice that tracks versions of node, npm, nginx, mongodb, and others

semver.io is a plaintext and JSON webservice that tracks all available versions of Node.js and use that version info to resolve semver range queries. It's used by Heroku's Node.js buildpack and is open-sourced on GitHub. Community members have contributed semver-as-a-service support for other projects like npm, iojs, nginx, and MongoDB.