Dynamic / Ephemeral Port (49152–65535) Regex for JavaScript

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching dynamic / ephemeral port (49152–65535), 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

// Dynamic / Ephemeral Port (49152–65535)
// ReDoS-checked | RegexVault — Web & Network > Port

const dynamicEphemeralPort4915265535Regex = /^(?:6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|6[0-4][0-9]{3}|5[0-9]{4}|4[9][0-9]{3})$/;

function validateDynamicEphemeralPort4915265535(input: string): boolean {
  return dynamicEphemeralPort4915265535Regex.test(input);
}

// Example
console.log(validateDynamicEphemeralPort4915265535("49152")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Web & Network > Port category and has been checked for ReDoS risk. 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

Ephemeral range 49152-65535. Pattern covers 49000-65535 — validate the lower bound (>=49152) with integer comparison for precision. Linux ephemeral range (32768-60999) may differ from IANA spec.