Package License Viewer

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Shows the license of every dependency inline at the end of the line, with the license itself colored so it stands out at a glance.

// package.json
{
  "dependencies": {
    "lodash": "^4.17.21",        // MIT
    "@babel/core": "^7.0.0",     // MIT
    "left-pad": "1.3.0",         // WTFPL
    "axios": "^1.1.1"            // MIT (Node: >=20)
  },
  "devDependencies": {
    "typescript": "^5.7.2"       // Apache-2.0
  }
}

Hover an annotation to see the resolved version, where the information came from, and a link to the package homepage.

Supported languages

Language	Support	Package managers	Contributor	Notes
JavaScript / TypeScript	✅	npm, pnpm, yarn (classic & berry), bun	@otnc	package.json, plus deno.json/jsr.json/import_map.json and pnpm workspace catalogs
Deno / JSR	✅	jsr, npm: specifiers	@otnc	Same manifests as above — jsr: and npm: specifiers are both resolved
Rust	✅	Cargo	@bem130	Cargo.toml declarations resolved against crates.io / Cargo.lock; no local Cargo install needed
MoonBit	✅	moon	@Allianaab2m	moon.mod / moon.mod.json resolved against .mooncakes, the local registry index and mooncakes.io; no local moon install needed
Python	❌	pip, uv, poetry		Planned — Issue #14
Ruby	❌	bundler, gem		Planned — Issue #15
Go	❌	go mod		Planned — Issue #16

See docs/resolution-details.md for exactly how each language resolves a license, per-package-manager notes, and known metadata gaps (e.g. JSR).

Editors

Editor	Support	Notes
VS Code	✅	The full feature set: inline annotations, hover, and every packageLicenseViewer.* setting.
Neovim	✅ (experimental)	Inline annotations, hover, and setting sync, via a bundled Node language server plus a Lua layer (vim.lsp.start(), nvim_buf_set_extmark()). The server currently has to be built locally (npm run compile:lsp, or a plugin manager's build hook) — see :help package_license_viewer.
Vim	✅ (experimental)	Same as Neovim, through the plugin's own VimScript LSP client (job/channel + prop_add/popup_atcursor). Needs Vim 9.0+ with +job, +channel and +textprop — see :help package_license_viewer.

The Vim/Neovim plugin lives at packages/vim-plugin; see its :help package_license_viewer for setup and configuration.

Commands

Command	Description
Package License Viewer: Refresh License Annotations	Re-read local metadata, lockfiles and Cargo workspace declarations, then redraw. Use after dependency changes.
Package License Viewer: Clear License Cache	Drop everything cached from the registries.
Package License Viewer: Toggle Inline License Annotations	Turn the annotations on or off.

Settings

Setting	Default	Description
packageLicenseViewer.enabled	true	Show inline license annotations.
packageLicenseViewer.format	${license}	Annotation template. Placeholders: ${license}, ${version}, ${name}, ${source}, ${nodeEngine}.
packageLicenseViewer.showResolvedVersion	false	Append the resolved version, e.g. MIT · 4.17.21.
packageLicenseViewer.showNodeEngine	true	Append the package's engines.node range, when it has one, e.g. MIT (Node: >=20).
packageLicenseViewer.unknownText	""	Text shown when the license is unknown. Empty means show nothing.
packageLicenseViewer.annotationColor	editorCodeLens.foreground	Theme color id, or a CSS color such as #88888899, for everything except the license itself.
packageLicenseViewer.licenseColor	charts.green	Theme color id, or a CSS color, used for just the license part of the annotation.
packageLicenseViewer.margin	0 0 0 1.5em	CSS margin before the annotation.
packageLicenseViewer.cacheTtlHours	168	Lifetime of cached registry results. 0 disables the on-disk cache.
packageLicenseViewer.requestTimeoutMs	8000	Timeout of a single registry request.
packageLicenseViewer.maxConcurrentRequests	8	Parallel registry requests.
packageLicenseViewer.npm.enabled	true	Enable annotations for package.json.
packageLicenseViewer.npm.registry	https://registry.npmjs.org	Registry base URL.
packageLicenseViewer.npm.useRegistry	true	Allow registry lookups. Set to false to stay fully offline.
packageLicenseViewer.npm.useLockfiles	true	Read lockfiles for exact pinned versions.
packageLicenseViewer.npm.sections	4 standard sections	Sections that are always annotated.
packageLicenseViewer.npm.autoDetectSections	true	Also annotate other top-level objects whose key ends with dependencies.
packageLicenseViewer.npm.pnpmWorkspaceCatalogs	true	Also annotate the catalog: and catalogs: sections of pnpm-workspace.yaml.
packageLicenseViewer.jsr.enabled	true	Enable annotations for Deno / import map manifests.
packageLicenseViewer.jsr.registry	https://jsr.io	JSR registry base URL.
packageLicenseViewer.jsr.apiUrl	https://api.jsr.io	JSR API base URL, where the license lives.
packageLicenseViewer.crates.enabled	true	Annotate dependency declarations in Cargo.toml.
packageLicenseViewer.crates.useRegistry	true	Allow crates.io requests. When disabled, existing cached public metadata can still be used.
packageLicenseViewer.crates.useLockfiles	true	Prefer a uniquely matching crates.io version in the applicable Cargo.lock.
packageLicenseViewer.moonbit.enabled	true	Annotate dependency declarations in moon.mod / moon.mod.json.
packageLicenseViewer.moonbit.useRegistry	true	Allow mooncakes.io requests. When disabled, installed modules, the local registry index and existing cached metadata are still used.
packageLicenseViewer.moonbit.useRegistryIndex	true	Read the registry index moon update keeps in $MOON_HOME/registry/index, so an installed toolchain resolves without any request.

Contributing

Adding a new ecosystem is one interface: LicenseProvider. See CONTRIBUTING.md for the architecture and contribution workflow.

Contributors

Author

otoneko. https://github.com/otnc

License

MIT