Semantic Version (Full SemVer 2.0.0) Regex for Python

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching semantic version (full semver 2.0.0), ported and verified for Python. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Python project — whether you're validating in a Django view, a FastAPI endpoint, or a standalone data processing script.

Python Implementation

# Semantic Version (Full SemVer 2.0.0)
# ReDoS-safe | RegexVault — Dev & Systems > SemVer

import re

semantic_version_full_semver_200_pattern = re.compile(r'^(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)(?:-((?:0|[1-9][0-9]*|[0-9]*[a-zA-Z\-][a-zA-Z0-9\-]*)(?:\.(?:0|[1-9][0-9]*|[0-9]*[a-zA-Z\-][a-zA-Z0-9\-]*))*))?(?:\+([a-zA-Z0-9\-]+(?:\.[a-zA-Z0-9\-]+)*))?$')

def validate_semantic_version_full_semver_200(value: str) -> bool:
    return bool(semantic_version_full_semver_200_pattern.fullmatch(value))

# Example
print(validate_semantic_version_full_semver_200("1.0.0"))  # True

Test Cases

When to use this pattern

This pattern is drawn from the Dev & Systems > SemVer category and carries a ReDoS-safe certification. That matters for Python developers because particularly important in Python web servers where CPU-bound regex operations can stall concurrent request handling. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

Official SemVer 2.0.0 regex from semver.org. Capture groups: 1=MAJOR, 2=MINOR, 3=PATCH, 4=pre-release, 5=build metadata. Leading zeros in numeric identifiers are forbidden.