Wallet Integration

What This Is

Wallet integration on the Internet Computer uses the ICRC signer standards — a popup-based model where every action requires explicit user approval via JSON-RPC 2.0 over window.postMessage.

This skill covers integration using @dfinity/oisy-wallet-signer. Other integration paths (IdentityKit, signer-js) exist but are not covered here.

The signer model = explicit per-action approval. connect() establishes a channel. Nothing more.

It is not:

• A session system
• A delegated identity (no ICRC-34)
• A background executor

ICRC standards implemented:

• ICRC-21 — Canister call consent messages
• ICRC-25 — Signer interaction standard (permissions)
• ICRC-27 — Accounts
• ICRC-29 — Window PostMessage transport
• ICRC-49 — Call canister

Not implemented:

• ICRC-46 — Session-based delegation (not supported; use a delegation-capable model if you need sessions)

When to Use

• Clear, intentional, high-value actions: token transfers (ICP / ICRC-1 / ICRC-2), NFT mint/claim, single approvals
• Funding / deposit flows: "Top up", "Deposit into protocol"
• Any action where a confirmation dialogue per operation feels natural

When NOT to Use

• Delegation or sessions: sign once / act many times, background execution, autonomous behaviour
• High-frequency interactions: games, social actions, rapid write operations
• Invisible writes: autosave, cron jobs, auto-compounding

Decision test: If your app still feels good when every meaningful update shows a confirmation dialogue, this library is appropriate. If not, use a delegation-capable model instead.

Prerequisites

• @dfinity/oisy-wallet-signer installed
• Peer dependencies installed: @dfinity/utils, @dfinity/zod-schemas, @icp-sdk/canisters, @icp-sdk/core, zod
• A non-anonymous identity on the signer side (e.g. Ed25519KeyIdentity)
• For local development: a running local network (icp network start -d)

npm i @dfinity/oisy-wallet-signer @dfinity/utils @dfinity/zod-schemas @icp-sdk/canisters @icp-sdk/core zod

How It Works

End-to-End Lifecycle

1. dApp: IcrcWallet.connect({url})              → opens popup, polls icrc29_status
2. dApp: wallet.requestPermissionsNotGranted()   → prompts user if needed
3. dApp: wallet.accounts()                       → signer prompts, returns accounts
4. dApp: wallet.transfer({...})                  → signer fetches ICRC-21 consent message
                                                    → signer prompts user with consent
                                                    → signer executes canister call
                                                    → returns block index
5. dApp: wallet.disconnect()                     → closes popup, cleans up

Pitfalls

1. Importing classes from the wrong entry point. Signer, RelyingParty, IcpWallet, and IcrcWallet are not exported from the main entry point. Import them from their dedicated subpaths or you get undefined.

   // WRONG — will fail
   import {Signer} from '@dfinity/oisy-wallet-signer';
   
   // CORRECT
   import {Signer} from '@dfinity/oisy-wallet-signer/signer';
   import {IcpWallet} from '@dfinity/oisy-wallet-signer/icp-wallet';
   import {IcrcWallet} from '@dfinity/oisy-wallet-signer/icrc-wallet';
   

2. Using IcrcWallet without ledgerCanisterId. Unlike IcpWallet (which defaults to the ICP ledger ryjl3-tyaaa-aaaaa-aaaba-cai), IcrcWallet.transfer(), .approve(), and .transferFrom() all require ledgerCanisterId. Omitting it causes a runtime error.

3. Forgetting to register prompts on the signer side. The signer returns error 501 (PERMISSIONS_PROMPT_NOT_REGISTERED) if a request arrives and no prompt handler is registered for it. Register all four prompts (ICRC25_REQUEST_PERMISSIONS, ICRC27_ACCOUNTS, ICRC21_CALL_CONSENT_MESSAGE, ICRC49_CALL_CANISTER) before the signer can handle any relying party traffic.

4. Sending concurrent requests to the signer. The signer processes one request at a time. A second request while one is in-flight returns error 503 (BUSY). Serialize your calls — wait for each response before sending the next. Read-only methods (icrc29_status, icrc25_supported_standards) are exempt.

5. Assuming connect() = authenticated session. connect() only opens a postMessage channel. The user has not pre-authorized anything. Permissions default to ask_on_use — the signer will prompt the user on first use of each method. Call requestPermissionsNotGranted() after connecting to request all permissions upfront in a single prompt instead of per-method prompts.

6. Not handling the consent message state machine. The ICRC21_CALL_CONSENT_MESSAGE prompt fires multiple times with different statuses: loading → result | error. If you only handle result, the UI breaks on loading and error states. Always branch on payload.status.

7. sender not matching owner. The signer validates that sender in every icrc49_call_canister request matches the signer's owner identity. A mismatch returns error 502 (SENDER_NOT_ALLOWED). Always use the owner from accounts().

8. Not calling disconnect(). Both Signer.disconnect() and wallet.disconnect() must be called on clean-up. Forgetting this leaks event listeners and leaves popup windows open.

9. Ignoring permission expiration. Permissions default to a 7-day validity period. After expiry, they silently revert to ask_on_use. Don't cache permission state client-side beyond a session.

10. Auto-triggering signing on connect. Never fire a canister call immediately after connect(). Let the user initiate the action. The signer is designed for intentional, user-driven operations.

Implementation

Import Map

// Constants, errors, and types — from main entry point
import {
  ICRC25_REQUEST_PERMISSIONS,
  ICRC25_PERMISSION_GRANTED,
  ICRC25_PERMISSION_DENIED,
  ICRC25_PERMISSION_ASK_ON_USE,
  ICRC27_ACCOUNTS,
  ICRC21_CALL_CONSENT_MESSAGE,
  ICRC49_CALL_CANISTER,
  DEFAULT_SIGNER_WINDOW_CENTER,
  DEFAULT_SIGNER_WINDOW_TOP_RIGHT,
  RelyingPartyResponseError,
  RelyingPartyDisconnectedError
} from '@dfinity/oisy-wallet-signer';

import type {
  PermissionsPromptPayload,
  AccountsPromptPayload,
  ConsentMessagePromptPayload,
  CallCanisterPromptPayload,
  IcrcAccounts,
  SignerOptions,
  RelyingPartyOptions
} from '@dfinity/oisy-wallet-signer';

// Classes — from dedicated subpaths
import {Signer} from '@dfinity/oisy-wallet-signer/signer';
import {RelyingParty} from '@dfinity/oisy-wallet-signer/relying-party';
import {IcpWallet} from '@dfinity/oisy-wallet-signer/icp-wallet';
import {IcrcWallet} from '@dfinity/oisy-wallet-signer/icrc-wallet';

dApp Side (Relying Party)

Choosing the Right Class

Connect, Permissions, Accounts

const wallet = await IcrcWallet.connect({
  url: 'https://your-wallet.example.com/sign', // URL of the wallet implementing the signer
  host: 'https://icp-api.io',
  windowOptions: {width: 576, height: 625, position: 'center'},
  connectionOptions: {timeoutInMilliseconds: 120_000},
  onDisconnect: () => {
    /* wallet popup closed */
  }
});

const {allPermissionsGranted} = await wallet.requestPermissionsNotGranted();

const accounts = await wallet.accounts();
const {owner} = accounts[0];

IcpWallet — ICP Transfers and Approvals

Uses {owner, request} — no ledgerCanisterId needed.

const wallet = await IcpWallet.connect({url: 'https://your-wallet.example.com/sign'});
const accounts = await wallet.accounts();
const {owner} = accounts[0];

await wallet.icrc1Transfer({
  owner,
  request: {to: {owner: recipientPrincipal, subaccount: []}, amount: 100_000_000n}
});

await wallet.icrc2Approve({
  owner,
  request: {spender: {owner: spenderPrincipal, subaccount: []}, amount: 500_000_000n}
});

IcrcWallet — Any ICRC Ledger

Uses {owner, ledgerCanisterId, params} — ledgerCanisterId is required.

const wallet = await IcrcWallet.connect({url: 'https://your-wallet.example.com/sign'});
const accounts = await wallet.accounts();
const {owner} = accounts[0];

await wallet.transfer({
  owner,
  ledgerCanisterId: 'mxzaz-hqaaa-aaaar-qaada-cai',
  params: {to: {owner: recipientPrincipal, subaccount: []}, amount: 1_000_000n}
});

await wallet.approve({
  owner,
  ledgerCanisterId: 'mxzaz-hqaaa-aaaar-qaada-cai',
  params: {spender: {owner: spenderPrincipal, subaccount: []}, amount: 5_000_000n}
});

await wallet.transferFrom({
  owner,
  ledgerCanisterId: 'mxzaz-hqaaa-aaaar-qaada-cai',
  params: {from: {owner: fromPrincipal, subaccount: []}, to: {owner: toPrincipal, subaccount: []}, amount: 1_000_000n}
});

Query Methods and Disconnect

const standards = await wallet.supportedStandards();
const currentPermissions = await wallet.permissions();

await wallet.disconnect();

Error Handling (dApp Side)

try {
  await wallet.transfer({...});
} catch (err) {
  if (err instanceof RelyingPartyResponseError) {
    switch (err.code) {
      case 3000: /* PERMISSION_NOT_GRANTED */ break;
      case 3001: /* ACTION_ABORTED — user rejected */ break;
      case 4000: /* NETWORK_ERROR */ break;
    }
  }
  if (err instanceof RelyingPartyDisconnectedError) {
    /* popup closed unexpectedly */
  }
}

Wallet Side (Signer)

Initialise and Register All Prompts

const signer = Signer.init({
  owner: identity,
  host: 'https://icp-api.io',
  sessionOptions: {
    sessionPermissionExpirationInMilliseconds: 7 * 24 * 60 * 60 * 1000
  }
});

signer.register({
  method: ICRC25_REQUEST_PERMISSIONS,
  prompt: ({requestedScopes, confirm, origin}: PermissionsPromptPayload) => {
    confirm(
      requestedScopes.map(({scope}) => ({
        scope,
        state: userApproved ? ICRC25_PERMISSION_GRANTED : ICRC25_PERMISSION_DENIED
      }))
    );
  }
});

signer.register({
  method: ICRC27_ACCOUNTS,
  prompt: ({approve, reject, origin}: AccountsPromptPayload) => {
    approve([{owner: identity.getPrincipal().toText()}]);
  }
});

signer.register({
  method: ICRC21_CALL_CONSENT_MESSAGE,
  prompt: (payload: ConsentMessagePromptPayload) => {
    if (payload.status === 'loading') {
      // show spinner
    } else if (payload.status === 'result') {
      // payload.consentInfo: { Ok: ... } (from canister) or { Warn: ... } (signer-generated fallback)
      // show consent UI, then: payload.approve() or payload.reject()
    } else if (payload.status === 'error') {
      // show error, optionally payload.details
    }
  }
});

signer.register({
  method: ICRC49_CALL_CANISTER,
  prompt: (payload: CallCanisterPromptPayload) => {
    if (payload.status === 'executing') {
      /* show progress */
    } else if (payload.status === 'result') {
      /* call succeeded */
    } else if (payload.status === 'error') {
      /* call failed */
    }
  }
});

Consent Message: Ok vs Warn

• { Ok: consentInfo } — canister implements ICRC-21; message is canister-verified
• { Warn: { consentInfo, canisterId, method, arg } } — signer generated a fallback (for icrc1_transfer, icrc2_approve, icrc2_transfer_from)

Always distinguish these in the UI — warn the user when the message is signer-generated.

Disconnect

signer.disconnect();

Error Code Reference

Permission States

Permissions stored in localStorage as oisy_signer_{origin}_{owner} with timestamps. Default validity: 7 days.

Deploy & Test

Local Development — Your Own Signer

If you are building both the dApp and the wallet/signer, start a local network and pass host to both sides:

icp network start -d

// dApp side — point to your local wallet's /sign route
const wallet = await IcrcWallet.connect({
  url: 'http://localhost:5174/sign',
  host: 'http://localhost:8000'
});

// Wallet/signer side — same local network host
const signer = Signer.init({
  owner: identity,
  host: 'http://localhost:8000'
});

Local Development — Using the Pseudo Wallet Signer

If you are building a dApp (relying party) and need a signer to test against locally, the library provides a pseudo wallet signer in its demo:

git clone https://github.com/dfinity/oisy-wallet-signer
cd oisy-wallet-signer
npm ci

cd demo
npm ci
npm run sync:all
npm run dev:wallet    # starts the pseudo wallet on port 5174

Then connect from your dApp:

const wallet = await IcpWallet.connect({
  url: 'http://localhost:5174/sign',
  host: 'http://localhost:8000' // match your local network port
});

Mainnet

On mainnet, point to the wallet's production signer URL and omit host (defaults to https://icp-api.io):

const wallet = await IcpWallet.connect({
  url: 'https://your-wallet.example.com/sign'
});

Expected Behavior

Connection

• connect() resolves with a wallet instance; throws RelyingPartyDisconnectedError on timeout
• wallet.supportedStandards() returns an array containing at least ICRC-21, ICRC-25, ICRC-27, ICRC-29, ICRC-49

Permissions

• requestPermissionsNotGranted() triggers the signer's permissions prompt
• After approval, wallet.permissions() returns scopes with state granted
• A second call returns {allPermissionsGranted: true} without prompting again

Accounts

• wallet.accounts() returns at least one {owner: string} (principal as text)
• The returned owner matches the signer's identity principal

Transfers and Approvals

• icrc1Transfer() / transfer(), icrc2Approve() / approve(), and transferFrom() all resolve with a bigint block index
• Each triggers the consent message prompt on the signer before execution