Package.json Validator — Audit and Fix Node.js Project Files
Paste any package.json to instantly validate required fields, check semver version ranges in dependencies, and flag script name issues. Catches missing name/version fields, invalid semver ranges, and unpinned wildcards.
How to Use Package.json Validator — Audit and Fix Node.js Project Files
How to Use the package.json Validator:
Step 1: Paste Your package.json
Copy the contents of your package.json file and paste it into the input area. The validator analyses it in real-time — no button click needed.
Step 2: Load an Example (Optional)
Click one of the example buttons to load a pre-built package.json:
- React App — a well-formed package.json with valid semver ranges
- Invalid Semver — shows how invalid and unpinned version strings are flagged
- Missing Fields — demonstrates errors when name, version, and other required fields are absent
Step 3: Read the Status Banner
A green banner means the file has no errors (warnings may still appear). A red banner shows the error count and, for JSON parse failures, the exact parse error message.
Step 4: Review the Overview Cards
The Overview section shows counts for top-level fields, scripts, dependencies, dev dependencies, errors, and warnings at a glance.
Step 5: Fix Issues from the List
The Issues section lists every problem found, sorted errors first then warnings. Each row shows:
- ERROR / WARNING badge
- The field path (e.g.,
dependencies.axios) - A plain-English message explaining the problem
What Gets Validated
Errors (must fix):
- Missing required fields:
nameandversion namecontains uppercase letters, spaces, or invalid charactersnameexceeds 214 charactersversionis not a valid semver string (e.g., must be1.2.3not1.2)- Dependency version is not a valid semver range (e.g.,
newest,>=4 && <5) - Script name has leading or trailing whitespace
- Script value is not a string
Warnings (best practice):
- Missing recommended fields:
descriptionandlicense - Dependency uses
latest— pin to a range for reproducible installs - Dependency uses
*— accepts any version, risks unexpected breakage - Script command is an empty string
Valid Semver Range Formats
The following formats are accepted in dependencies, devDependencies, peerDependencies, and optionalDependencies:
- Exact:
1.2.3,v1.2.3 - Caret:
^1.2.3(compatible with) - Tilde:
~1.2.3(approximately) - Comparators:
>=1.0.0,<2.0.0,>=1.0.0 <2.0.0 - Hyphen range:
1.0.0 - 2.0.0 - OR range:
^1.2.3 || ^2.0.0 - Wildcards:
*,1.x,1.2.x - Partial:
1,1.2 - Special:
latest,file:../pkg,git+https://...,workspace:*
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