How to Hash Passwords in Node.js

Pattern

const hash = await argon2.hash(password);

the argon2 package — defaults to Argon2id with a random salt generated automatically

Explanation

The argon2 package (npm install argon2) is the current recommended choice for Node.js — it wraps the real, native Argon2 reference implementation, not a pure-JS reimplementation, and defaults to Argon2id with a random salt generated automatically. You never call a separate salt-generation function; it's baked into hash().

const argon2 = require("argon2");

const hash = await argon2.hash(password);
const ok = await argon2.verify(hash, password);

Both functions are async and return Promises — hash() resolves to the full encoded hash string (algorithm, version, parameters, salt, and digest all packed together), and verify() resolves to a plain boolean, unpacking those embedded parameters from the hash itself rather than needing them passed in separately.

To set parameters explicitly instead of relying on the library's defaults — OWASP's baseline is m=19456, t=2, p=1:

const hash = await argon2.hash(password, {
  type: argon2.argon2id,
  memoryCost: 19456,
  timeCost: 2,
  parallelism: 1,
});

For the full mechanics of what each of these parameters actually controls, see Argon2 Explained.

Valid examples

const hash = await argon2.hash(password); // "$argon2id$v=19$m=65536,t=3,p=4$..."
Defaults to Argon2id. The salt, algorithm, and every parameter are embedded in the returned string — nothing extra to store separately.
const ok = await argon2.verify(hash, password); // true or false
Reads the parameters back out of hash itself, so verification always uses whatever settings the hash was actually created with.
await argon2.hash(password, { type: argon2.argon2id, memoryCost: 19456, timeCost: 2, parallelism: 1 });
Explicit OWASP-baseline parameters instead of the library defaults.

Invalid examples

const hash = argon2.hash(password); // missing await
hash() is async — without await, hash is a pending Promise object, not a string, and that's what gets saved to the database.
require("crypto").createHash("sha256").update(password).digest("hex")
A raw SHA-256 digest — no salt, no cost factor, computable at billions per second on a GPU. See Why SHA-256 Should Not Be Used for Passwords.
if (hash === computeHash(password)) { /* login */ }
Manually recomputing and comparing with === instead of calling verify() — skips the constant-time comparison the library provides, and won't work at all once the hash has an embedded salt.

Try it now

Password Hash Generator

Generate bcrypt, scrypt, Argon2, and PBKDF2 password hashes.