Docker Port Mapping Regex for JavaScript

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching docker port mapping, 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

// Docker Port Mapping
// ReDoS-safe | RegexVault — Dev & Systems > Docker

const dockerPortMappingRegex = /^(?:(?:(?:(?:25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9])\.){3}(?:25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9]):)?(?:6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|6[0-4][0-9]{3}|[1-5][0-9]{4}|[1-9][0-9]{0,3}):)?(?:6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|6[0-4][0-9]{3}|[1-5][0-9]{4}|[1-9][0-9]{0,3})(?:\/(tcp|udp|sctp))?$/i;

function validateDockerPortMapping(input: string): boolean {
  return dockerPortMappingRegex.test(input);
}

// Example
console.log(validateDockerPortMapping("8080:80")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Dev & Systems > Docker 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

Protocol defaults to tcp. Exposing on 0.0.0.0 (all interfaces) is the default. Use 127.0.0.1 to restrict to localhost for development services.