Is anything sent to a server or npm?

No. The comparison runs entirely in your browser using a self-contained implementation. No package registry or network request is involved, so nothing you type is sent anywhere.

How accurate are the range rules?

It implements the node-semver rules deterministically — caret expands to a range that keeps the left-most non-zero field, tilde allows patch-level changes, wildcards and hyphen ranges expand to comparator pairs, and pre-release versions follow the spec ordering (numeric identifiers rank below alphanumeric and a version without a pre-release outranks one with).

Why does a pre-release version not satisfy a range?

Per the semver spec, a pre-release like 2.0.0-rc.1 is considered lower than 2.0.0 and is treated cautiously by ranges. Check the expanded comparators shown beneath the result to see exactly what bounds were applied.

Semver Range Checker

Semver range checker

Check whether a semantic version satisfies an npm-style range — instantly and offline.

It supports the full node-semver range syntax: caret (^1.2.0), tilde (~1.2), wildcards (1.x, 1.2.x, *), hyphen ranges (1.2.3 - 2.3.4), explicit comparators (>=1.0.0 <2.0.0) and OR sets joined with ||. Pre-release tags are ordered per the spec.

The result shows whether the version matches and the expanded comparator set used, so the verdict is transparent. Everything runs in your browser — no package registry is ever contacted.