Validate package.json

Check a package manifest for npm fields, types, and publish-time mistakes.

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Toolpackage.json Validator
Input
Output
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How it works

The JSON is parsed and checked for name, version, scripts, dependency maps, entry fields, and common metadata types. Findings identify risks without publishing or installing anything.

  • Checks follow npm’s documented fields.
  • Warnings remain advisory for private registries and custom policies.

Worked example

Validate a package.json
Check for required fields and common issues
Input
											{"name":"my-app","version":"1.0.0","scripts":{"dev":"next dev"}}
Output
												# package.json Validation

Name: my-app
Version: 1.0.0
Errors: 0 | Warnings: 4

## Warnings
  - Missing 'description' field
  - Missing 'license' field
  - Missing 'repository' field
  - Missing 'keywords' field

## Info
  - Scripts: dev

package.json is valid!

When to use this

Publish CI, editor checks, and monorepo audits validate package manifests.

Edge cases

  • Uppercase package names violate npm naming rules.
  • A non-SemVer version blocks normal publishing.
  • Putting a runtime dependency in devDependencies changes production installs.

References