OpenAI API Key Regex for JavaScript

What this pattern does

This page provides a well-structured, multi-part regular expression for matching openai api key, ported and verified for JavaScript. In security-sensitive code, using an unverified regex can open the door to both false positives and denial-of-service attacks. 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

// OpenAI API Key
// ReDoS-safe | RegexVault — Security > API Keys & Tokens

const openaiApiKeyRegex = /^sk-(?:proj-)?[A-Za-z0-9]{20}T3BlbkFJ[A-Za-z0-9]{20}$|^sk-[A-Za-z0-9_-]{20,128}$/;

function validateOpenaiApiKey(input: string): boolean {
  return openaiApiKeyRegex.test(input);
}

// Example
console.log(validateOpenaiApiKey("sk-aBcDeFgHiJkLmNoPqRsT3BlbkFJuVwXyZ0123456789AB")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Security > API Keys & Tokens 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

Older OpenAI keys use the sk-{48chars} format with 'T3BlbkFJ' (base64 for 'OpenAI') as a recognizable substring. Newer project-scoped keys use sk-proj- prefix. Both patterns are included.