Hardware random numbers for Node.js. The client uses your CPU's own hardware generator when it has one: RDRAND on Intel and AMD x86_64, RNDR on ARMv8.5+ such as AWS Graviton3 and Graviton4. Otherwise (and if the hardware ever fails to deliver) it calls the free rdrand.com API. No API key is needed. Results have the same formats either way.

Node.js 18 or later, no dependencies. The hardware path ships prebuilt for linux-x64, linux-arm64, win32-x64, darwin-x64 and darwin-arm64 (Apple silicon has no RNDR, so it uses the API).

npm install https://rdrand.com/Downloads/jebtek-rdrand-2.0.0.tgz

const { RdRand } = require('@jebtek/rdrand');   // or: import { RdRand } from '@jebtek/rdrand'

const rng = new RdRand();                  // mode 'auto'
const key = await rng.generateKey(32);     // 32 chars from 0-9 A-Z _ a-z
const bytes = await rng.generateBytes(16); // Buffer of 16 random bytes
const n = await rng.generateUInt();        // 0 .. 2^31 - 1

console.log(rng.source);                   // 'rdrand', 'rndr' or 'service'
console.log(RdRand.hardwareSource());      // the CPU's generator, or null

Options: new RdRand({ mode, baseUrl, timeoutMs }) with mode one of 'auto' (hardware, else API), 'hardware' (rejects with RdRandError without a hardware generator) or 'service' (API only).

License: MIT, Copyright © 2014-2026 JebteK, LLC.