Check an npm major upgrade for breaking changes
Compare two exact npm versions for vulnerabilities, runtime support, dependency changes, and cited migration work.
UpgradeLens is a read-only MCP and REST service for npm and PyPI. It returns proceed, review_required, block, or unknown with evidence links and ordered migration actions.
Agent-ready request
curl -X POST https://upgradelens.mattpicone.workers.dev/v1/upgrade/review -H 'content-type: application/json' -d '{"ecosystem":"npm","package":"zod","current_version":"3.25.0","target_version":"4.0.0","detail":"compact"}'