World Developer Docs

The @worldcoin/idkit-standalone package is discontinued. Migrate any vanilla JavaScript or custom QR flow to @worldcoin/idkit-core.

Migration Checklist

Enable World ID 4.0 in the Developer Portal and keep your app_id, rp_id, and server-only signing_key.
Install @worldcoin/idkit-core.
Add a backend endpoint that generates an RP signature. See RP Signatures.
Pick a legacy preset that matches your previous verification_level configuration.
Replace verifyCloudProof(...) with a backend POST to https://developer.world.org/api/v4/verify/{rp_id}.
Store the verified nullifier for replay protection.

For the broader protocol migration, including proof types and timelines, see World ID 4.0.

Install

npm i @worldcoin/idkit-core

pnpm add @worldcoin/idkit-core

yarn add @worldcoin/idkit-core

Request a Proof

Standalone mounted UI through browser globals:

Before

import "@worldcoin/idkit-standalone";

IDKit.init({
  app_id: "app_xxxxx",
  action: "my-action",
  signal: "user-123",
  verification_level: "orb",
});

await IDKit.open();

With idkit-core, fetch an RP signature from your backend, build the request, render the connectorURI, and poll until World ID returns a proof.

After

import { IDKit, orbLegacy } from "@worldcoin/idkit-core";

const action = "my-action";
const signal = "user-123";

const rpContext = await fetch("/api/rp-signature", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({ action }),
}).then((r) => r.json());

const request = await IDKit.request({
  app_id: "app_xxxxx",
  action,
  rp_context: {
    rp_id: "rp_xxxxx",
    nonce: rpContext.nonce,
    created_at: rpContext.created_at,
    expires_at: rpContext.expires_at,
    signature: rpContext.sig,
  },
  allow_legacy_proofs: true,
  environment: "production",
}).preset(orbLegacy({ signal }));

renderQrCode(request.connectorURI);

const completion = await request.pollUntilCompletion({
  pollInterval: 2_000,
  timeout: 120_000,
});

if (!completion.success) {
  throw new Error(`World ID verification failed: ${completion.error}`);
}

await fetch("/api/verify-proof", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({ idkitResponse: completion.result }),
});

Credential Mapping

Standalone used verification_level to choose what the user proves. In idkit-core, use a legacy preset instead. These presets only return World ID 3.0 proofs — a compatibility step, not the final migration target.

Legacy presets return the maximum credential a user has. For example, if a user has an Orb credential but you request documentLegacy, they verify with their Orb credential.

Standalone	`idkit-core` preset (compatibility-only)
`verification_level: "orb"`	`orbLegacy({ signal })`
`verification_level: "secure_document"`	`secureDocumentLegacy({ signal })`
`verification_level: "document"`	`documentLegacy({ signal })`
`verification_level: "device"`	`deviceLegacy({ signal })`

For World ID 4.0, use the v4-native presets: proofOfHuman (replaces orbLegacy), passport (NFC passports/eIDs), or mnc (Japanese My Number Card). They always keep World ID 3.0 fallback on, regardless of allow_legacy_proofs. A single preset narrows a document integration, since documentLegacy accepted Orb, passport/eID, and MNC holders alike; to keep all of them, use .constraints(any(CredentialRequest("proof_of_human"), CredentialRequest("passport"), CredentialRequest("mnc"))). Constraint requests have no credential-specific 3.0 fallback (any 3.0 fallback is Device-level), so use them with allow_legacy_proofs: false, which is also how you drop World ID 3.0 entirely. See Configure Credentials.

import {
  IDKit,
  deviceLegacy,
  documentLegacy,
  orbLegacy,
  secureDocumentLegacy,
} from "@worldcoin/idkit-core";

const request = await IDKit.request(config).preset(
  orbLegacy({ signal: "user-123" }),
);

RP Signatures

IDKit 4.x requests require rp_context, signed by your backend with the Developer Portal signing_key. Never generate signatures in client code. For implementation details, see the RP Signatures reference. It includes the JavaScript helper, the signing algorithm, and test vectors for non-JavaScript backends.

Verify the Proof

Standalone integrations typically verified with verifyCloudProof(...):

Before

import { verifyCloudProof } from "@worldcoin/idkit";

const response = await verifyCloudProof(proof, app_id, action, signal);

In IDKit 4.x, send the IDKit result to your backend and forward it directly to the v4 verify endpoint.

After

import type { IDKitResult } from "@worldcoin/idkit-core";

export async function POST(request: Request): Promise<Response> {
  const { idkitResponse } = (await request.json()) as {
    idkitResponse: IDKitResult;
  };

  const response = await fetch(
    `https://developer.world.org/api/v4/verify/${process.env.WORLD_ID_RP_ID}`,
    {
      method: "POST",
      headers: { "content-type": "application/json" },
      body: JSON.stringify(idkitResponse),
    },
  );

  return new Response(await response.text(), {
    status: response.status,
    headers: { "content-type": "application/json" },
  });
}

Store the Nullifier

After /api/v4/verify/{rp_id} succeeds, store the verified nullifier for the action and reject duplicates. During migration, keep checking any old nullifier_hash records if the same user could have verified before the upgrade.

Overview

IDKit

Sandbox

Credentials

Migration

Technical Reference

IDKit Standalone

Migration Checklist

Install

Request a Proof

Credential Mapping

RP Signatures

Verify the Proof

Store the Nullifier

​Migration Checklist

​Install

​Request a Proof

​Credential Mapping

​RP Signatures

​Verify the Proof

​Store the Nullifier

Migration Checklist

Install

Request a Proof

Credential Mapping

RP Signatures

Verify the Proof

Store the Nullifier