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Open source

k6/x/tls

Note

This module is implemented as an official extension and is available natively in k6, requiring no additional installation or build steps. Refer to the extensions documentation for available extensions and details.

The k6/x/tls module provides functionality for TLS certificate validation and inspection, allowing you to fetch certificate details and validate their properties directly from your k6 tests.

Use cases

  • Fetch TLS certificate information from any host
  • Validate certificate expiration and properties
  • Access certificate details (for example subject, issuer, fingerprint)

API

getCertificate( hostname )

Fetches TLS certificate information from a specified host.

The tls.getCertificate function retrieves TLS certificate details from a given hostname and returns a promise that resolves to a certificate object containing various properties such as expiration date, subject, issuer, and fingerprint information.

Parameters

ParameterTypeDescription
hostnamestringThe hostname to fetch the TLS certificate from. For example, “example.com” or “k6.io”.

Returns

A promise resolving to a certificate object containing the following properties:

PropertyTypeDescription
subjectobjectThe certificate subject information (pkixName object)
issuerobjectThe certificate issuer information (pkixName object)
issuednumberThe certificate issued timestamp in milliseconds since Unix epoch
expiresnumberThe certificate expiration timestamp in milliseconds since Unix epoch
fingerprintstringThe certificate fingerprint

Examples

Check if a certificate is expired

JavaScript 
import tls from "k6/x/tls";
import { check } from "k6";

export default async function () {
  const cert = await tls.getCertificate("example.com");

  check(cert, {
    "certificate is not expired": (c) => c.expires > Date.now(),
  });

  console.log(`Certificate expires: ${new Date(cert.expires)}`);
}