Semver Tester – Validate Version Formats

Validate semantic version formats and test compatibility. Fully client-side.

Need to compare or increment versions? Try our Semver Calculator.

Enter a semantic version to validate its format

Enter multiple versions to validate them all at once

What is a Semver Tester?

A semver tester (semantic version tester) is a specialized tool that validates and tests semantic version strings according to the semantic versioning specification. Unlike a semver calculator that compares or increments versions, a semver tester focuses on validation and compatibility testing.

Our semver tester helps you:

  • Validate version formats: Check if version strings follow Semantic Versioning 2.0.0 specification (e.g., 1.2.3, 2.0.0-alpha, 1.5.0+20240101). Matches npm & semantic-release behavior.
  • Test version requirements: Verify if a version meets a requirement (e.g., does 1.2.3 satisfy >=1.0.0?). Supports ^, ~, >=, >, <=, <, =, and compound ranges.
  • Check version ranges: Test if a version falls within a specified range (e.g., >=1.0.0 <2.0.0). Shows which bound failed (lower/upper) with explanations.
  • Batch validation: Validate multiple versions at once for dependency management
  • Compatibility checking: Test version compatibility for package managers like npm, yarn, and pnpm

Whether you're managing dependencies, validating package versions, or testing version constraints, our semver tester provides instant validation and testing results.

How to Use the Semver Tester

Using our semver tester is straightforward. Choose your testing mode and follow these steps:

Step 1: Choose Testing Mode

Select from three modes: Validate Format (check if version format is valid), Test Requirement (test if version meets a requirement), or Test Range (test if version is within a range).

Step 2: Enter Version and Requirements

Enter your version string (e.g., 1.2.3) and, if testing requirements or ranges, enter the requirement or range (e.g., >=1.0.0, <2.0.0, ~1.2.0, ^1.0.0).

Step 3: View Results

The tool instantly validates your version or tests it against requirements. Results show whether the version is valid, meets requirements, or falls within ranges, with detailed explanations.

Step 4: Batch Validation (Optional)

For multiple versions, use the batch validation feature. Enter one version per line, and the tool will validate all versions at once, showing which are valid and which have errors.

Examples

Example 1: Validate Version Format

Input: 1.2.3

Result: Valid semantic version

Details: Major: 1, Minor: 2, Patch: 3, Pre-release: none, Build: none

Example 2: Test Requirement

Version: 1.5.0

Requirement: >=1.0.0

Result: Requirement met - 1.5.0 is greater than or equal to 1.0.0

Example 3: Test Range

Version: 1.5.0

Range: >=1.0.0 <2.0.0

Result: In range - 1.5.0 is within the specified range

Use Cases

Our semver tester is used by developers, DevOps engineers, and package maintainers for various version validation and testing tasks:

  • Dependency Management: Validate and test package versions before adding dependencies to your project
  • CI/CD Pipelines: Automate version validation in continuous integration workflows
  • Package Publishing: Validate version formats before publishing packages to npm, PyPI, or other registries
  • Version Constraints: Test if versions meet dependency requirements specified in package.json, requirements.txt, or other manifest files
  • Compatibility Checking: Verify version compatibility across different package versions and dependencies
  • Error Debugging: Identify invalid version formats that cause dependency resolution errors

The semver tester is especially valuable for anyone working with semantic versioning in JavaScript/TypeScript projects (npm, yarn, pnpm), Python projects (pip, poetry), and other package management systems that use semantic versioning.

Related developer tools

Explore these related free tools to enhance your productivity and workflow.

Semantic Version Calculator

Compare and increment semantic versions

Regex Tester

Test regular expressions with match highlighting and common patterns

JSON Validator

Validate JSON syntax with error detection and location highlighting

Frequently Asked Questions

What is a semver tester, checker, or validator?

A semver tester/checker/validator verifies that a version string follows SemVer 2.0.0 and checks if it meets a requirement. It validates the format (e.g., 1.2.3), tests compatibility (e.g., >=1.0.0), and reports invalid versions for dependency management and package versioning.

Is this a semver validator?

Yes. This tool validates semantic version formats against the SemVer 2.0.0 specification and explains why a version is valid or invalid.

How do I test if a version meets a requirement?

Enter your version (e.g., 1.2.3) and a requirement with an operator (e.g., >=1.0.0, <2.0.0, ~1.2.0, ^1.0.0). The tool will test if your version satisfies the requirement. Operators include: >= (greater than or equal), <= (less than or equal), > (greater than), < (less than), = (equals), ~ (compatible within same minor), ^ (compatible within same major).

What's the difference between semver tester and semver calculator?

A semver tester/checker validates version formats and tests compatibility against requirements. A semver calculator compares two versions or increments version numbers. Use the tester to validate/check, and the calculator to compare or bump versions.

How do I validate multiple versions at once?

Use the batch validation feature. Enter multiple versions, one per line, in the batch validation section. The tool will validate each version and show which ones are valid and which are invalid, along with error messages for invalid formats.

What version formats are supported?

The tool supports Semantic Versioning 2.0.0 specification exactly: MAJOR.MINOR.PATCH (e.g., 1.2.3). It also supports pre-release versions (1.2.3-alpha, 1.2.3-beta.1) with correct precedence rules, and build metadata (1.2.3+20240101). The tool validates that all components are properly formatted according to SemVer 2.0.0, rejecting leading zeros, empty identifiers, and invalid formats. Matches npm & semantic-release behavior.

What do the ~ and ^ operators mean?

The tilde (~) operator means compatible within the same minor version. For example, ~1.2.3 means >=1.2.3 <1.3.0. The caret (^) operator means compatible within the same major version. For example, ^1.2.3 means >=1.2.3 <2.0.0. These are commonly used in package managers like npm.

How do I test version ranges?

Enter your version and a range in the format '>=1.0.0 <2.0.0' or '1.0.0 - 2.0.0'. The tool will test if your version falls within the specified range. This is useful for testing dependency version constraints and compatibility ranges.

Is the semver tester free to use?

Yes! Our semver tester is 100% free with no registration required, no usage limits, and no hidden fees. You can validate and test as many versions as you need for your development work.

Are my versions stored or tracked?

No, all version testing happens locally in your browser. We don't store, save, or have access to any versions you test. Your privacy is completely protected.

Can I use this for npm package version testing?

Yes. The tool follows the SemVer 2.0.0 specification used by npm and many package managers. You can validate package versions, test dependency requirements, and check version compatibility.