HTTP Request Log Line Regex for JavaScript

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching http request log line, 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

// HTTP Request Log Line
// ReDoS-safe | RegexVault — Dev & Systems > Log Parsing

const httpRequestLogLineRegex = /^(?:(?!FETCH)(?:GET|POST|PUT|DELETE|PATCH|HEAD|OPTIONS) [^\s]+ [0-9]{3}(?: [0-9]+ms| elapsed=[0-9]+ms)?|method=[A-Z]+ path=[^\s]+ status=[0-9]{3} duration=[0-9]+ms)$/i;

function validateHttpRequestLogLine(input: string): boolean {
  return httpRequestLogLineRegex.test(input);
}

// Example
console.log(validateHttpRequestLogLine("GET /api/users 200 125ms")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Dev & Systems > Log Parsing 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

Groups: 1=HTTP method, 2=path, 3=status code, 4=duration (optional). The pattern is flexible on surrounding key=value formatting to handle multiple log styles.