Semver Range Explainer

Paste a semver range like ^1.2.3 or ~4.0 to get a plain-English explanation and see which versions match.

What is Semantic Versioning?

Semantic Versioning (semver) is a versioning convention using the format MAJOR.MINOR.PATCH (e.g., 1.4.2). MAJOR increments indicate breaking changes, MINOR increments add functionality backwards-compatibly, and PATCH increments fix bugs backwards-compatibly.

npm, yarn, and most package managers use semver range expressions in package.json to specify which versions of a dependency are acceptable. Understanding these ranges helps you avoid unexpected breaking changes.

Common Range Operators

^ (caret) — Compatible changes. ^1.2.3 accepts >=1.2.3 <2.0.0. This is npm's default.
~ (tilde) — Patch-level changes only. ~1.2.3 accepts >=1.2.3 <1.3.0.
>=, <=, >, < — Explicit comparison operators.
1.2.3 - 2.0.0 — Inclusive range (hyphen range).
* or x — Any version.
|| (or) — Multiple ranges: ^1.0.0 || ^2.0.0.

Common Use Cases

Auditing package.json — Understand which versions of each dependency your project accepts.
Writing peer dependencies — Specify correct ranges for peerDependencies in npm packages.
Debugging version conflicts — Check if two packages' requirements for the same dependency are compatible.

Frequently Asked Questions

What does ^ mean in package.json?

The caret (^) allows compatible changes. For ^1.2.3, npm will accept any version >=1.2.3 and <2.0.0. It assumes any version within the same major version is backward-compatible. This is the default behavior when you run npm install package-name.

What is the difference between ~ and ^ in semver?

Tilde (~) is more conservative: ~1.2.3 only accepts patch-level changes (>=1.2.3 <1.3.0). Caret (^) is more permissive: ^1.2.3 accepts minor and patch changes (>=1.2.3 <2.0.0). Use tilde when you want tighter version control, caret for more flexibility.

Should I use exact versions or ranges in package.json?

For applications, use a lockfile (package-lock.json or yarn.lock) with flexible ranges — the lockfile pins exact versions. For libraries, be careful with ranges to avoid forcing duplicate installs on consumers. Exact versions give reproducibility but prevent security patches from being automatically applied.