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Semver Checker - Validate & Compare Semantic Versions

Check, validate, and compare semantic version numbers (MAJOR.MINOR.PATCH) with our free online Semver Checker. Test if versions follow semver rules, compare two versions, and ensure your releases use proper versioning.

What is Semver Checker - Validate & Compare Semantic Versions?

Semver Checker is a free online tool that validates and compares semantic version numbers following the SemVer 2.0.0 specification. It takes two version strings (like 2.1.3 and 2.2.0) and compares them numerically by MAJOR, MINOR, and PATCH segments. All processing happens locally in your browser — no data is sent to any server.

When to Use

  • Verifying that a package version follows correct semver format before publishing
  • Checking whether a dependency update is a breaking change (MAJOR), new feature (MINOR), or bug fix (PATCH)
  • Comparing npm package versions to understand upgrade impact
  • Debugging version conflicts in your project's dependency tree
  • Learning semantic versioning rules for open-source packages

How to Use

Type two version numbers separated by a space or newline in the input field (e.g., '1.2.3 2.0.0'), then click Process. The tool parses both versions and shows which is greater, lesser, or if they're equal. It also displays what each segment means — MAJOR for breaking changes, MINOR for features, PATCH for fixes.

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Deep Dive: How Semver Checker - Validate & Compare Semantic Versions Works

Semantic Versioning (SemVer) is a formal specification for assigning version numbers to software releases. It was created by Tom Preston-Werner in 2013 to solve the problem of 'dependency hell' — where upgrading one package could silently break another.

The core of SemVer is the MAJOR.MINOR.PATCH triplet. Given a version number 2.4.1, for example: - 2 (MAJOR): Version 2 introduced breaking changes from version 1 - 4 (MINOR): Four backward-compatible feature releases have been made since version 2.0 - 1 (PATCH): One bug fix release since version 2.4

When comparing versions, the rules are straightforward: compare MAJOR first; if equal, compare MINOR; if equal, compare PATCH. A version like 2.0.0 is always greater than 1.999.999 because the MAJOR segment takes precedence.

Pre-release versions like 1.0.0-alpha or 2.0.0-rc.1 have lower precedence than the release version (1.0.0-alpha < 1.0.0). Build metadata like 1.0.0+build.1234 is ignored for comparison but preserved for informational purposes.

Most package ecosystems enforce SemVer — npm, RubyGems, Packagist (PHP), Crates.io (Rust), and NuGet (.NET) all use or recommend it. Understanding SemVer is essential for any developer who publishes open-source packages or manages dependencies.

Pro Tips

  • Always bump MAJOR version for breaking changes, even if it seems minor — your users' tests will thank you
  • Use pre-release identifiers (like 1.0.0-beta.2) for development builds and release candidates
  • Start with 0.1.0 for the first release of a new project (0.y.z means unstable public API)
  • Pin your dependencies to MAJOR.MINOR to safely get patch updates without breaking changes

Common Mistakes to Avoid

  • Confusing MINOR and PATCH — adding new features requires a MINOR bump, not a PATCH
  • Changing public API without a MAJOR bump — even removing one optional parameter is a breaking change
  • Skipping version numbers during development (e.g., jumping from 1.0.0 to 2.0.0 without proper build testing)

Frequently Asked Questions

What is semantic versioning (SemVer)?
Semantic Versioning is a versioning scheme that uses a three-part number format: MAJOR.MINOR.PATCH. Increment the MAJOR version for breaking API changes, the MINOR version for backward-compatible new features, and the PATCH version for backward-compatible bug fixes. Before version 1.0.0 (major version zero), anything may change at any time. This system, defined at semver.org, helps developers understand the impact of dependency updates just by looking at the version number.
How do I compare two semver versions?
Enter two version numbers separated by a space (e.g., '1.2.3 1.3.0') and click Process. The tool compares them numerically by MAJOR, then MINOR, then PATCH. The result shows which version is greater, less, or if they're equal. For example, 2.0.0 > 1.9.9 because MAJOR version 2 is greater than 1, regardless of MINOR and PATCH numbers.
What do MAJOR, MINOR, and PATCH mean in practice?
MAJOR version changes indicate breaking changes — existing code that worked with the old version may not work with the new one. MINOR version changes add new functionality in a backward-compatible way — your existing code still works, but you gain access to new features. PATCH version changes are for backward-compatible bug fixes — no new features, just fixes that don't break existing functionality.
What about pre-release versions and build metadata?
SemVer also supports pre-release identifiers (e.g., 1.0.0-alpha, 2.0.0-rc.1) and build metadata (e.g., 1.0.0+build.20240101). Pre-release versions have lower precedence than the normal version. Build metadata is ignored when comparing precedence. Our checker handles these formats and compares them correctly.