Docker Image Digest (SHA256) Regex for JavaScript

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching docker image digest (sha256), 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 Image Digest (SHA256)
// ReDoS-safe | RegexVault — Dev & Systems > Docker

const dockerImageDigestSha256Regex = /^sha256:[a-fA-F0-9]{64}$/;

function validateDockerImageDigestSha256(input: string): boolean {
  return dockerImageDigestSha256Regex.test(input);
}

// Example
console.log(validateDockerImageDigestSha256("sha256:a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d00e8a7c22955b46d4")); // 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

64 hex characters = 256 bits = SHA-256 output. The sha256: prefix is mandatory for algorithm agility. Digest pinning provides immutable image references.