Anthropic API Key Regex for JavaScript

What this pattern does

This page provides a well-structured, multi-part regular expression for matching anthropic 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

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

const anthropicApiKeyRegex = /^sk-ant-[A-Za-z0-9_\-]{32,128}$/;

function validateAnthropicApiKey(input: string): boolean {
  return anthropicApiKeyRegex.test(input);
}

// Example
console.log(validateAnthropicApiKey("sk-ant-api03-aBcDeFgHiJkLmNoPqRsTuVwXyZ0123456789aBcDe")); // 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

Anthropic API keys use the sk-ant- prefix. Scoped to the organization. If leaked, immediately rotate at console.anthropic.com. Fine-grained API key scopes are available in the Anthropic Console.