Check access from your backend

Set up the Node.js library with a secret key first. This page covers deciding access: gate server-side features on a customer's active perk grants.

Check a perk

server/routes/export.ts

app.get("/reports/export", async (req, res) => {
  const hasPremium = await voidhash.entitlements.hasActivePerk({
    distinctId: req.user.id,
    perkSlug: "premium",
  });

  if (!hasPremium) {
    return res.status(402).json({ error: "premium_required" });
  }

  return res.json(await buildExport(req.user.id));
});

distinctId is the same identifier your app passed to identify(). Pass exactly one of perkId or perkSlug — both or neither rejects with VoidhashNodeConfigurationError before any request is made.

perkSlug costs one extra perks.listPerks round trip to resolve. On a hot path, resolve the slug to its id once at boot and pass perkId.

An unknown customer has no access

hasActivePerk returns false for a distinctId Voidhash has never seen, and for a perkSlug that matches no perk. It does not absorb authentication, authorization, 5xx, or transport failures — those reject, so a mistyped secret key can never be mistaken for "nobody has premium".

Read the grants yourself

When you need to render an account page, show an expiry date, or branch on where access came from, read the grants directly:

const grants = await voidhash.entitlements.getGrantsByDistinctId({
  distinctId: "user_123",
});

Field	Type	Notes
`perkId`	`string`	Match against the perk you care about.
`status`	`"active" \| "expired"`	Only `active` grants confer access.
`expiresAt`	`string \| null`	ISO timestamp; `null` never expires.
`source`	`"subscription" \| "purchase" \| "manual"`	How the grant was obtained.
`sourceId`	`string \| null`	The subscription or purchase behind it.
`sourcePersonId`	`string`	Differs from the person on shared plans.

Unlike hasActivePerk, an unknown distinctId is an error here, so the caller decides whether "never seen" and "seen, bought nothing" mean the same thing.

The same two calls are available separately when you already hold a personId:

const person = await voidhash.persons.getPersonByDistinctId({
  params: { distinctId: "user_123" },
});

const { grants } = await voidhash.persons.getPersonEntitlements({
  params: { personId: person.personId },
});

Person is intentionally thin — personId, distinctId, email, name — because it identifies the customer, it does not describe what they paid for.

Handle errors deliberately

A rejected API call carries the decoded server error on error.data, whose _tag is stable. Transport failures (DNS, TLS, timeouts) reject with an Effect HttpClientError that has no data.

const serverTag = (error: unknown): string | undefined =>
  (error as { data?: { _tag?: string } } | null)?.data?._tag;

try {
  const grants = await voidhash.entitlements.getGrantsByDistinctId({
    distinctId: "user_123",
  });

  return grants.some((grant) => grant.perkId === premiumPerkId && grant.status === "active");
} catch (error) {
  switch (serverTag(error)) {
    case "Api/PersonNotFoundError":
      // Never identified from a client: nothing was ever bought.
      return false;
    case "Api/NotAuthenticatedError":
    case "Api/ActionForbiddenError":
      // Our key is wrong. Our bug, not the customer's — do not lock them out.
      throw new Error("Voidhash secret key is invalid or lacks access.");
    default:
      throw error;
  }
}

Common tags: Api/NotAuthenticatedError (401), Api/ActionForbiddenError (403), Api/PersonNotFoundError (404), Api/WebhookEndpointNotFoundError (404), Api/WebhookValidationError (400).

Live and development data

Grants are scoped to an environment, and the server picks the scope from the x-environment request header:

`x-environment`	Grants returned
absent or `production`	Real purchases — store production and store sandbox
`development`	Only simulated purchases made by an SDK in a debug build
`all`	Both of the above

The SDK never sends the header for you, so a plain client always reads production and sandbox grants. To read development purchases, set the header on a separate client:

const voidhashDevelopment = createVoidhashSdk({
  secretKey: process.env.VOIDHASH_SECRET_KEY!,
  headers: { "x-environment": "development" },
});

Secret keys are not environment-scoped — which key you use does not change the answer, only the header does.

Any other value silently means production

An unrecognized x-environment value falls back to production instead of erroring. Never wire the header directly to something like NODE_ENV: a value of "test" would quietly read production grants.

Caching and failures

The SDK does not cache, retry, or de-duplicate. Every call is a live HTTP round trip.

For a check on every request, cache the result yourself for a short window — 60 seconds is a reasonable start — and refresh in the background.

When a call fails with a transport error or a 5xx, treat the answer as unknown, not as no access. Serve the last known good value, or fail the request. Revoking a paying customer's access because of a network blip is worse than a slightly stale cache.