Kubernetes Label / Annotation Value Regex for JavaScript

What this pattern does

This page provides a well-structured, multi-part regular expression for matching kubernetes label / annotation value, ported and verified for JavaScript. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your JavaScript project — whether you're validating in an Express middleware, a Next.js API route, or a client-side form.

Javascript Implementation

// Kubernetes Label / Annotation Value
// ReDoS-safe | RegexVault — Dev & Systems > Config

const kubernetesLabelAnnotationValueRegex = /^[a-zA-Z0-9](?:[a-zA-Z0-9_.\-]{0,61}[a-zA-Z0-9])?$|^$/;

function validateKubernetesLabelAnnotationValue(input: string): boolean {
  return kubernetesLabelAnnotationValueRegex.test(input);
}

// Example
console.log(validateKubernetesLabelAnnotationValue("production")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Dev & Systems > Config category and carries a ReDoS-safe certification. That matters for JavaScript developers because especially critical in long-running Node.js event loops where a ReDoS vulnerability can block the entire process. 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

Label values can be empty (for boolean-style presence checks). Must begin and end with alphanumeric if non-empty. Max 63 chars. Label keys have a separate format (optional prefix/name with different rules).