@zoreal/oauth2-node

Login with ZOREAL for Node.js backends: the relying-party half of the flow that @zoreal/oauth2-react starts in the browser.

The browser SDK runs the pairing (QR or app link), and hands your frontend an authorization code plus the code_verifier and nonce it generated. Your frontend posts all three to your backend, and this package does the rest: the code exchange with your client authentication, ES256 verification of the ID token against the provider's JWKS, and the /userinfo read for personal claims.

@zoreal/oauth2-node (this package)   your backend: exchange, verify, userinfo
@zoreal/oauth2-react                 your frontend: the button, the QR, the polling

Install

npm install @zoreal/oauth2-node

Node.js >= 18 (the built-in fetch is the transport). One dependency: jose. ESM and CommonJS builds ship, with types.

Getting your credentials

Everything the client constructor needs comes from a ZOREAL asset.

1. Create an account at https://zoreal.com and open Assets.
2. Create an asset — a website (a domain you own) or an app bundle (a reverse-DNS bundle id). An asset is the thing users log in to; its token is your clientId and it looks like ast_....
3. On the asset, open the OAuth2 tab and set:
   • the redirect URIs and JavaScript origins your app uses (requests from anything not registered are rejected — this is the core control),
   • the scopes the client is allowed to request (see the catalogue below),
   • your client authentication: generate a client secret (client_secret_basic), or register a JWKS for private_key_jwt. A public client authenticates with PKCE alone and no secret.
4. A website asset must verify its domain (a DNS or meta-tag proof, shown in the dashboard) before it can request personal-data scopes or sign users in; the verified domain is what your users' sub is pairwise against.

The clientId is public — it ships in your frontend. The client secret is not: keep it in your server's secret store (an environment variable, a secrets manager), never in the browser.

There is no test-identity sandbox — and that is deliberate

ZOREAL never issues fake or sandbox humans: a pool of test identities would be a fraud vector against the exact thing the product proves. So you always authenticate real ZOREAL IDs.

To develop and test, create a free ZOREAL ID for yourself (enrol in the ZOREAL ID app) and sign in with it. Mark your asset's environment sandbox in the dashboard while building — a sandbox asset may register http://localhost origins and redirect URIs that a production asset may not — and flip it to production when you ship. The identities are real either way; only the allowed origins differ.

Quick start

Build one client at boot and share it; it is safe to use concurrently.

import { ZorealOAuth2Client } from '@zoreal/oauth2-node';

export const zoreal = new ZorealOAuth2Client({
  clientId: process.env.ZOREAL_CLIENT_ID!,                       // ast_...
  issuer: process.env.ZOREAL_ISSUER ?? 'https://id.zoreal.com',
  auth: {
    method: 'client_secret_basic',
    clientSecret: process.env.ZOREAL_CLIENT_SECRET!,
  },
});

The endpoint your frontend posts to (Express here; any framework works the same way):

app.post('/api/auth/zoreal', async (req, res) => {
  const { code, code_verifier, nonce } = req.body;
  const login = await zoreal.authenticate(code, code_verifier, nonce);

  login.sub;                   // "TC5X-JN7G-YTSE-6E63" — pairwise, stable for YOUR domain
  login.acr;                   // "zoreal.live" | "zoreal.device" | "zoreal.session"
  login.assurance;             // uniqueness basis, verification month, chip liveness, trust tier
  await login.email();         // from /userinfo, when your client has the email scope
  await login.emailVerified();
  await login.name();          // from /userinfo, profile.name scope
});

Account matching, the shape that works:

let user = await users.findBy({ provider: 'zoreal', uid: login.sub });
if (!user) {
  if (await login.emailVerified()) {
    user = await users.findBy({ email: await login.email() }); // claim, don't collide
  }
  user ??= await users.create({ email: await login.email() });
  await users.update(user, { provider: 'zoreal', uid: login.sub });
}

Assurance levels — acr, and requiring a liveness check

What acr is

acr is an OpenID Connect standard claim — Authentication Context Class Reference. It is a single string in the ID token that says how strongly this particular login was authenticated. Every ZOREAL login carries one, and it is the difference between "someone who once enrolled this identity is behind this request" and "a live human, verified to be the right one, is behind this request right now".

It answers a question the sub cannot. sub tells you who (a stable, pairwise identifier for this person at your site). acr tells you how sure ZOREAL is that the person is really there for this login. A stolen, unlocked phone can still produce a sub; it cannot produce a fresh zoreal.live.

The three levels

Ordered weakest to strongest. Each is what actually happened, never what was requested — a login that could only reach a weaker level says so honestly rather than claiming the level you asked for.

acr	What the holder did	amr	What it proves	What it does not prove
zoreal.session	Nothing — a returning holder at a site they have used before, resumed silently from an existing ZOREAL session, no phone interaction	[]	Continuity: the same browser/session ZOREAL already knew	That the holder is present, or even awake
zoreal.device	Approved the login on their enrolled phone: a signature from a key in the phone's secure element, released by a local biometric or passcode unlock	["hwk","user"]	Possession of the enrolled device and a local unlock on it	That a live face was captured for this login — an unlocked phone in the wrong hands still signs
zoreal.live	All of the above plus a fresh face capture this login: a flash-plus-zoom video scored for presentation attacks and screen replay (moire), matched 1:1 against the government document read at enrolment	["hwk","face","user"]	A live, real, unique human, verified to be the enrolled person, at the moment of this login	— (this is the strongest level)

amr (Authentication Methods References) is the companion claim listing the factors used: hwk a hardware key, user a user-presence/unlock gesture, face a face biometric. zoreal.live is exactly zoreal.device with face added, because a live login is a device approval with a capture on top. The package exports the same ordering as the frozen ACR_ORDER constant, if you want the ranks directly.

The default is zoreal.device, never zoreal.session: a login that asks for nothing still requires the enrolled phone and a local unlock. Silence has to be explicitly asked for (prompt=none), and it succeeds only for a returning holder at a site whose consent they have already given.

When to require which

• zoreal.session — you never require this; it is what a returning holder gets for a low-stakes convenience re-auth when they ask for the silent path.
• zoreal.device (the default) — a forum, a community, a normal account login. Possession of the enrolled phone plus a local unlock is a high bar already; most sites want exactly this and should pass no acr at all.
• zoreal.live — a bank onboarding, a high-value transaction, an age-gated purchase, a first login, a "confirm it is really you" step before a sensitive action. Anywhere a fresh, unforgeable proof of the live, right human is worth the few seconds a face capture costs.

Requesting versus verifying — the one rule that matters

Requesting a level and verifying it are two separate steps, and only the second is security:

1. Request it on the wire, in the frontend, with the SDK's acr_values: 'zoreal.live'. This is what makes the holder's ZOREAL ID app run the face capture before it will approve. It is advisory — it shapes what the holder is asked to do, nothing more. A browser is attacker-controlled; a value that only travels through it proves nothing.
2. Verify it here, at token exchange, by passing acr on the verification options. The signed acr claim in the ID token — minted by ZOREAL, not by the browser — is the proof.

const login = await zoreal.authenticate(code, code_verifier, {
  nonce,
  acr: 'zoreal.live', // rejects with VerificationError unless the signed token says so
});

login.acr;                           // "zoreal.live" — what actually happened
login.live;                          // convenience: acr === 'zoreal.live'
login.satisfiesAcr('zoreal.device'); // true (live is stronger than device)

An RP that requests zoreal.live on the wire but never passes acr here has checked nothing — it has only asked the holder nicely and then trusted a value it never validated.

How the check behaves

Verification satisfies upward: zoreal.session < zoreal.device < zoreal.live, so a requirement of zoreal.device accepts a zoreal.live token (the holder gave you more assurance than you demanded). A token whose acr is below the requirement, missing entirely, or outside the vocabulary is refused with VerificationError. An unknown required value — a typo like 'zoreal.liveness' — throws ConfigurationError instead, because that is a bug in your code, not a bad token, and failing every login silently is worse than saying so.

If you prefer to branch rather than throw, omit acr and inspect the result with the satisfiesAcr predicate:

const login = await zoreal.authenticate(code, code_verifier, nonce);
if (!login.satisfiesAcr('zoreal.live')) {
  // step the user up, or refuse the sensitive action
}

satisfiesAcr runs the same ordering as the floor check and returns false for anything it cannot rank, so it never throws: the predicate is the branch-yourself path, and the acr option is the enforce-for-me path.

acr versus the assurance block

Do not confuse acr with login.assurance. acr grades this login event. The assurance block (login.assurance, the zoreal claim) describes the identity behind it — how the person was verified at enrolment: the uniqueness basis, the verified_on month, whether chip liveness was proven (chip_liveness_proven), the trust_tier, and the device's key_protection. One is about now; the other is about who they are. A high-value flow usually wants both: acr: 'zoreal.live' for presence, and the assurance block for the strength of the underlying identity proofing. Its full schema is in The assurance block below.

Client authentication

Four registrable methods; auth takes exactly one of them.

// Public client (the default): no secret, no key. PKCE is the only proof,
// and Tier A scopes are all such a client can have been granted.
auth: { method: 'none' }

// Confidential: the secret travels as HTTP Basic, never as a form field.
auth: { method: 'client_secret_basic', clientSecret: '...' }

// Confidential: the package builds and signs a fresh RFC 7523 assertion per
// exchange. PEM string (PKCS8 or SEC1/PKCS1), node KeyObject, or CryptoKey.
auth: { method: 'private_key_jwt', privateKey: pem, kid: 'key-2026' }

// Mutual TLS at the transport. Read the note below before picking this.
auth: { method: 'tls_client_auth', cert, key }

private_key_jwt signs iss = sub = your client_id, aud = {issuer}/token, exp 60 seconds out (the provider's maximum), and a fresh jti per assertion, because the provider accepts each one exactly once. A P-256 key signs ES256, which is the preferred pairing and the one that matches the provider's certified-key path; an RSA key signs RS256. Other curves are refused at configuration time rather than at the provider.

tls_client_auth is registrable, but the provider currently answers 501 — not implemented at this endpoint yet — and this package surfaces that as the ExchangeError it is rather than faking the method. The certificate and key are applied through undici's Agent, so undici is an optional peer dependency you install only for this method: npm install undici. The other three methods never load it.

What each call does

Call	What happens
authenticate(code, codeVerifier, options?)	exchange + verifyIdToken, returns a Login
exchange(code, codeVerifier)	POST {issuer}/token with your client authentication
verifyIdToken(jwt, options?)	ES256 against {issuer}/jwks, checks iss, aud, exp, plus nonce and the acr floor when given
userinfo(accessToken)	GET {issuer}/userinfo with the Bearer token
login.userinfo()	the above, once, memoized; {} when there is no access token

options is the nonce string alone — the common case, as in the quick start — or { nonce?, acr? }.

Login also carries sub, acr, live, satisfiesAcr(required), amr, assurance, ageOver(threshold), nationality, claims, idToken, accessToken and scope, plus async accessors for every /userinfo claim: email(), emailVerified(), name(), givenName(), familyName(), birthdate(), documentType(), documentNumber(), issuingCountry(), documentExpiresOn(), portrait().

Scopes and claims

Scopes are requested in the frontend (the SDK's scope string, always starting with openid), consented to by the holder, and pre-authorized on your asset. What each grants and where it is delivered:

Scope	Claims	Delivered in	Tier	Requires
openid	sub, iss, aud, exp, iat, nonce, auth_time, acr, amr, and the assurance block	ID token	A	any client
zoreal.age	age_over_13/16/18/21/65 booleans — only the thresholds you registered, never an age or birthdate	ID token	A	any client
zoreal.nationality	nationality (ISO 3166-1 alpha-3)	ID token	A	any client
email	email, email_verified	/userinfo	B	confidential client + verified domain
profile.name	name, given_name, family_name	/userinfo	B	confidential client + verified domain
profile.birthdate	birthdate (full ISO 8601 date)	/userinfo	B	confidential client + verified domain
profile.document	document_type, document_number, issuing_country, document_expires_on	/userinfo	B	confidential client + verified domain
profile.portrait	portrait (the chip's facial image; GDPR Article 9 data)	/userinfo	C	confidential client + verified domain — registrable but not served yet

• Tier A rides in the ID token and is available to every client, so the no-backend browser button can use it. Read it straight off the Login: login.sub, login.acr, login.amr, login.assurance, login.ageOver(18), login.nationality.
• Tier B and C are personal data, served only from /userinfo to a confidential client on a domain you have verified, and never placed in a browser token. They arrive through the async accessors — await login.email(), await login.name(), and the rest — each of which reads /userinfo once and memoizes it.
• Age thresholds are a fixed set — 13, 16, 18, 21, 65 — that you register on the asset. login.ageOver(n) returns undefined for a threshold you did not register (no claim was minted), which is different from false.

Error reference

exchange / authenticate reject with ExchangeError, which carries the provider's own oauthError code and description verbatim (and the HTTP status when there was a response). What you will actually see:

oauthError	Cause	Retryable?
invalid_grant	The code is spent — unknown, expired (60s), already used, PKCE mismatch, or the asset's domain verification lapsed mid-flow	No. Start a new login; the code cannot be reused
invalid_request	Client authentication failed — wrong secret, a bad private_key_jwt assertion, or tls_client_auth (not accepted at /token yet)	No. Fix your client configuration
unsupported_grant_type	Something other than authorization_code reached /token	No. A bug

Errors that surface in the frontend instead, before your backend is involved (from the SDK's onError / onNonOAuthError), so handle them there:

Where	Code	Meaning
/pair	invalid_scope	A scope not on the asset's allowed list, or a Tier B scope from a public client
/pair	invalid_request	Missing PKCE/nonce, an unverified sector, an unregistered redirect_uri, or an unknown acr_values
/pair	login_required	prompt=none with no silent session to resume — the expected quiet outcome, not a failure
pairing	request_denied	The holder declined in their ZOREAL ID app — not an error to alarm on; offer to try again
pairing	request_expired	The pairing window elapsed, or a required liveness the device could not meet — offer to try again

request_denied is a person choosing not to log in, not a fault: treat it as a cancel — keep the button where it is and let them try again. It never reaches your backend, so there is nothing to catch here for it.

This package's own classes, all extending ZorealOAuth2Error:

Class	Thrown when	Extra fields
ConfigurationError	You built the client wrong, or asked to verify an acr outside the vocabulary — a bug in your code, not a bad token	—
ExchangeError	The provider refused the code exchange	oauthError, description, status?
VerificationError	The ID token did not verify: signature, iss, aud, exp, nonce, or the acr floor	—
UserinfoError	The /userinfo read failed	status?

A returning user matched on sub can survive a caught UserinfoError; a signup that needs the email cannot. No token value ever appears in an error message.

The assurance block

login.assurance is the ID token's zoreal claim (typed ZorealAssurance) — a description of the strength of the identity behind this login, distinct from acr, which grades the login event. Its keys and their value sets:

Key	Values	Meaning
uniqueness	personal_number | document | none	The anchor the holder is deduplicated on. personal_number (a national number from the chip) is strongest; none means no reliable anchor
verified_on	"YYYY-MM"	The month the underlying document was verified. Quantised to a month on purpose — a day-precision date is a cross-site correlator
chip_liveness_proven	true | false	Whether the passport chip's active-authentication challenge was proven (a genuine chip, not a clone)
trust_tier	high | standard	high when chip_liveness_proven, else standard
key_protection	secure_enclave | strongbox | tee | software	How the holder's device key is protected. software means no hardware attestation

acr grades the login event; the assurance block grades the identity. A high-value flow usually pairs the two — acr: 'zoreal.live' for fresh presence, and an assurance-block check for identity strength:

const login = await zoreal.authenticate(code, code_verifier, {
  nonce,
  acr: 'zoreal.live',
});

const { uniqueness, trust_tier } = login.assurance ?? {};
if (uniqueness !== 'personal_number' || trust_tier !== 'high') {
  // strong enough to sign in, not strong enough for THIS action: step up or refuse
}

A complete example

An Express handler, end to end — the shape a real integration takes.

import { ExchangeError, VerificationError, UserinfoError } from '@zoreal/oauth2-node';
import { zoreal } from './zoreal'; // the client built once at boot, from Quick start

// Your frontend's <ZorealLogin onSuccess> posts { code, code_verifier, nonce }
// here over your own TLS. Protect THIS route with your framework's normal CSRF /
// same-origin defence, exactly as you would any login endpoint — the ZOREAL
// nonce protects the token, not your route.
app.post('/api/auth/zoreal', async (req, res) => {
  const { code, code_verifier, nonce } = req.body;

  try {
    const login = await zoreal.authenticate(code, code_verifier, nonce);
    // pass { nonce, acr: 'zoreal.live' } instead for a step-up / high-value login

    let user = await users.findBy({ provider: 'zoreal', uid: login.sub });
    if (!user) {
      // A subject we have not seen. A signup needs personal data, so a
      // UserinfoError here is fatal — the returning path above never reaches it.
      const email = (await login.emailVerified()) ? await login.email() : undefined;
      // Claim an existing account that owns this verified email rather than
      // colliding on the unique index; otherwise create one.
      if (email) user = await users.findBy({ email });
      user ??= await users.create({ email, fullName: await login.name() });
      await users.update(user, { provider: 'zoreal', uid: login.sub });
    }

    // Session-fixation defence: a fresh session id on privilege change.
    await new Promise<void>((resolve, reject) =>
      req.session.regenerate((err: unknown) => (err ? reject(err) : resolve())),
    );
    req.session.userId = user.id;
    res.json({ ok: true });
  } catch (error) {
    if (error instanceof ExchangeError || error instanceof VerificationError) {
      // A spent code or a token that did not verify: the login must be restarted.
      return res.status(401).json({ error: 'sign_in_failed' });
    }
    if (error instanceof UserinfoError) {
      // Personal data was unreachable. Fine for a returning user matched on sub;
      // fatal for a signup that needs the email, as here.
      return res.status(401).json({ error: 'sign_in_failed' });
    }
    throw error; // an unexpected error is not a failed login; let it surface
  }
});

Things worth knowing before you integrate

• The ID token never carries personal data. sub, timing, acr/amr, the assurance block, and — if registered — age_over_* booleans and nationality. Email, names, birthdate and document fields come only from /userinfo, which is why authenticate alone is not enough for a signup.
• The access token lives 10 minutes. Read /userinfo while handling the login; do not store the token for later.
• sub is pairwise per verified domain. It is the right account key and it is derived from your registered sector: changing your asset's domain rotates every sub you have stored. Plan domain changes as a migration.
• ES256 only. The provider signs ID tokens with nothing else, and this package refuses other algorithms rather than negotiating.
• Email is a deliberate choice. It is a Tier B scope precisely because a shared email defeats the unlinkability the pairwise sub provides. Request it because you need it, not because the checkbox is familiar.
• profile.portrait is registrable but not served yet. The portrait() accessor exists so the integration is written once; it resolves undefined until the provider ships the claim.

Security

• Always pass the nonce through, and protect your own endpoint too. The SDK generates the nonce and hands it to your frontend in onSuccess; passing it to authenticate lets this package confirm the ID token was minted for this login rather than substituted. Two things the nonce does not do: it is not your endpoint's CSRF token — protect your /api/auth/zoreal route with your framework's normal CSRF / same-origin defence — and PKCE, not the nonce, is what proves whoever exchanges the code is whoever started the flow.
• PKCE is mandatory and already handled. The browser SDK generates the verifier and challenge; your frontend forwards the code_verifier, and exchange presents it. There is no plain, non-PKCE path to fall back to.
• The issuer must match the token's iss exactly. It is compared as a string, not normalized. Production is https://id.zoreal.com; set issuer to anything else only when you were handed a non-production provider URL to point at, and make it match that provider's iss character for character.

Verifying this release

Every version is published from GitHub Actions with npm provenance: the package page on npmjs.com carries a Provenance panel linking the exact commit and workflow run that built the tarball, signed through Sigstore and recorded in its public transparency log. No long-lived npm token stands behind it — the workflow authenticates by OIDC (trusted publishing), so a leaked CI secret cannot cut a release.

Check the signatures on what you actually installed:

npm install @zoreal/oauth2-node
npm audit signatures

The ZOREAL OAuth2 library family

Repository	Package	Role
zoreal-oauth2-react	@zoreal/oauth2-react (npm)	React frontend: the button, the QR, the polling
zoreal-oauth2-js	@zoreal/oauth2-js (npm)	Framework-free browser core
zoreal-oauth2-react-native	@zoreal/oauth2-react-native (npm)	React Native frontend
zoreal-oauth2-node	@zoreal/oauth2-node (npm)	Node.js backend
zoreal-oauth2-ruby	zoreal-oauth2 (RubyGems)	Ruby backend
zoreal-oauth2-python	zoreal-oauth2 (PyPI)	Python backend
zoreal-oauth2-php	zoreal/oauth2 (Packagist)	PHP backend
zoreal-oauth2-go	github.com/Bynn-Intelligence/zoreal-oauth2-go	Go backend
zoreal-oauth2-java	com.zoreal:oauth2 (Maven Central)	JVM backend
zoreal-oauth2-dotnet	Zoreal.OAuth2 (NuGet)	.NET backend

License

MIT.