This content originally appeared on DEV Community and was authored by Iz Mroen
What is package.json?
The package.json file is the manifest file of your Node.js project.
It contains:
- Metadata about your project (name, version, description, author, etc.)
- Scripts you can run (like start, build, test)
- Dependencies and devDependencies, listed with version ranges (^, ~, etc.)
This file is created manually (via npm init) and is meant to be human-readable and editable.
What is package-lock.json?
The package-lock.json file is automatically generated when you run npm install.
It:
- Locks the exact versions of every dependency and sub-dependency
- Ensures consistent installs across different machines and environments
- Makes installation faster by skipping version resolution (since it’s already defined)
| Feature | package.json |
package-lock.json |
|---|---|---|
| Purpose | Defines project metadata & dependencies | Locks exact versions for reproducible installs |
| Created by | Developer (manual / npm init) |
npm (auto-generated on install) |
| Versioning | Version ranges allowed (^, ~) |
Exact versions of all dependencies |
| Human editable? | Yes | No (should not be manually edited) |
| Consistency | Not guaranteed | Guaranteed same versions everywhere |
| Install speed | Slower (needs to resolve versions) | Faster (uses already resolved versions) |
| Commit to Git? | Yes (mandatory) | Yes (highly recommended) |
Why Both Files Are Important
-
package.jsonprovides flexibility: it allows updates to newer minor/patch versions of dependencies. -
package-lock.jsonensures stability: every developer and production environment installs exactly the same versions, avoiding “it works on my machine” problems.
This content originally appeared on DEV Community and was authored by Iz Mroen