Kastle Wallet API

Integrate your dApp with Kastle Wallet.

Note: This API is subject to changes. Refer to docs/index.js for the most up-to-date working examples.

Each API method is available in two styles:

• Direct method: kastle.methodName(...)

• KIP-style generic request: kastle.request('kas:method_name', args)

---

1. Detect Kastle

if (window.kastle) {
  console.log("Kastle Wallet detected!");
} else {
  alert("Please install Kastle Wallet.");
}

---

2. Connect

Opens the permission popup and requests wallet access.

Direct method

const isSuccess = await kastle.connect();
console.log("Connected:", isSuccess); // true

KIP-style

---

3. Get Version

Available since: Extension 2.48.0 · Mobile 1.19.0

Returns the current wallet version in SemVer format. The build metadata suffix identifies the platform:

Suffix	Platform
+extension	Browser extension
+mobile	Mobile app

Direct method

const version = await kastle.getVersion();
console.log("Version:", version);
// Browser extension: "2.47.0+extension"
// Mobile:            "1.19.0+mobile"

KIP-style

---

4. Get Account

Direct method

const { address, publicKey } = await kastle.getAccount();
console.log("Address:", address);
console.log("Public Key:", publicKey);

KIP-style

---

5. Get Network

Returns the currently active network ID.

Direct method

const network = await kastle.getNetwork();
console.log("Network:", network); // e.g. "mainnet"

KIP-style

---

6. Switch Network

Prompts the user to switch to a different network.

Direct method

// Valid values: "mainnet" | "testnet-10" | "testnet-11"
await kastle.switchNetwork("mainnet");

KIP-style

---

7. Get Balance

Available since: Extension 2.47.0 · Mobile 1.19.0

Returns the current account balance in sompi.

Direct method

const { balance } = await kastle.getBalance();
console.log("Balance (sompi):", balance);

KIP-style

---

8. Get UTXO Entries

Available since: Extension 2.47.0 · Mobile 1.19.0

Returns all UTXOs for the current account.

Direct method

const { entries } = await kastle.getUtxoEntries();
entries.forEach((entry) => {
  console.log(
    "Outpoint:",
    entry.outpoint.transactionId,
    ":",
    entry.outpoint.index,
  );
  console.log("Amount (sompi):", entry.amount);
  console.log("Is Coinbase:", entry.isCoinbase);
});

KIP-style

---

9. Send KAS

Builds, signs, and broadcasts a KAS transfer in one call. No RPC or WASM needed.

Parameters

Parameter	Type	Required	Description
toAddress	string	✅	Recipient Kaspa address
sompi	number	✅	Amount in sompi (minimum 0.2 KAS = 20,000,000 sompi)
options.priorityFee	number	❌	Priority fee in sompi (default: 0)
options.payload	string	❌	Transaction payload as a hex string (even length, 0-9 a-f only). Returns an error if the format is invalid.

Direct method

const txId = await kastle.sendKaspa(
  "kaspa:qr...recipient",
  100000000, // amount in sompi (1 KAS = 100,000,000 sompi)
  {
    priorityFee: 1000000, // optional, in sompi
    payload: "6b61737061", // optional hex string
  },
);
console.log("Transaction ID:", txId);

KIP-style

---

10. Build Transaction

Available since: Extension 2.47.0 · Mobile 1.19.0

Builds one or more transactions from the current account's UTXOs. Returns serialized txJson ready for signing. No RPC or WASM needed.

amount and priorityFee are strings (sompi) to avoid JS BigInt precision loss. May return multiple transactions when UTXO compounding is needed.

Parameters

Parameter	Type	Required	Description
outputs	{ address: string; amount: string }[]	✅	Recipient addresses and amounts (in sompi)
options.priorityFee	string	❌	Priority fee in sompi (default: "0")
options.payload	string	❌	Transaction payload as a hex string (even length, 0-9 a-f only). Returns an error if the format is invalid.
options.inputs	IUtxoEntry[]	❌	to use as inputs. If omitted, all UTXOs of the current account are used automatically.

IUtxoEntry schema

type IUtxoEntry = {
  address?: string;                          // Kaspa address (optional)
  outpoint: {
    transactionId: string;
    index: number;
  };
  amount: string;                            // sompi as string
  scriptPublicKey: {
    version: number;
    script: string;
  };
  blockDaaScore: string;
  isCoinbase: boolean;
};

Direct method

// Basic — uses all account UTXOs automatically
const { networkId, transactions } = await kastle.buildTransaction(
  [{ address: "kaspa:qr...recipient", amount: "100000000" }],
  {
    priorityFee: "1000000",
    payload: "6b61737061", // optional hex string
  },
);

// With explicit inputs
const { networkId, transactions } = await kastle.buildTransaction(
  [{ address: "kaspa:qr...recipient", amount: "100000000" }],
  {
    priorityFee: "1000000",
    inputs: [
      {
        address: "kaspa:qr...sender",
        outpoint: { transactionId: "abc123...", index: 0 },
        amount: "500000000",
        scriptPublicKey: { version: 0, script: "20ab...ac" },
        blockDaaScore: "443245436",
        isCoinbase: false,
      },
    ],
  },
);

for (const tx of transactions) {
  console.log("Tx ID:", tx.id);
  console.log("Fee:", tx.feeAmount, "sompi");
  console.log("Change:", tx.changeAmount, "sompi");
  console.log("Tx JSON:", tx.txJson);
}

KIP-style

---

11. Sign & Broadcast Transaction

Signs a transaction and broadcasts it to the network. Opens a confirmation popup.

Direct method

const txId = await kastle.signAndBroadcastTx(networkId, txJson);
console.log("Transaction ID:", txId);

KIP-style

To build txJson manually using Kaspa WASM and an RPC client, see docs/index.js.

---

12. Sign Transaction

Signs a transaction without broadcasting it. Returns the signed transaction as a JSON string. Useful for marketplace flows (e.g. SingleAnyOneCanPay).

Direct method

const signedTxJson = await kastle.signTx(networkId, txJson);

// Broadcast manually:
const { transactionId } = await rpc.submitTransaction(
  kaspaWasm.Transaction.deserializeFromSafeJSON(signedTxJson),
);

KIP-style

With a custom script (e.g. for P2SH spend):

const signedTxJson = await kastle.signTx(networkId, txJson, [
  { inputIndex: 0, scriptHex: "...", signType: "SingleAnyOneCanPay" },
]);

---

13. Sign Message

Signs an arbitrary message string.

Direct method

const signature = await kastle.signMessage("Hello from my dApp!");
console.log("Signature:", signature);

KIP-style

---

14. KRC-20: Transfer Token

KRC-20 operations use a commit-reveal pattern. Kastle handles both steps — no WASM needed.

Direct method

const result = await kastle.commitReveal(
  "mainnet",
  "kasplex",
  JSON.stringify({
    p: "krc-20",
    op: "transfer",
    tick: "MYTOKEN",
    to: "kaspa:qr...recipient",
    amt: "500",
  }),
);
console.log("Commit Tx ID:", result.commitTxId);
console.log("Reveal Tx ID:", result.revealTxId);

KIP-style

---

15. Compound UTXOs

Available since: Extension 2.52.0 · Mobile 1.20.0

Consolidates all UTXOs in the current account into a single UTXO by sending the full balance back to the sender's own address. Opens a confirmation popup.

Useful for reducing future transaction fees caused by having many small UTXOs.

Parameter	Type	Required	Description
options.priorityFee	string	❌	Priority fee in sompi (default: "0")

Direct method

const txId = await kastle.compoundUtxos({ priorityFee: "1000" });
console.log("Transaction ID:", txId);

KIP-style

16. Events

Listen to wallet state changes. Events are emitted in both KasWare-compatible and KIP-style formats simultaneously.

// KasWare-compatible
kastle.on("accountsChanged", (accounts) => {
  // string[] — empty array means disconnected
  console.log("Accounts changed:", accounts);
});

kastle.on("networkChanged", (network) => {
  console.log("Network changed:", network);
});

// KIP-style
kastle.on("kas:account_changed", (address) => {
  // string | null — null means disconnected
  console.log("Account changed:", address);
});

kastle.on("kas:network_changed", (network) => {
  console.log("Network changed:", network);
});

// Remove a listener
kastle.removeListener("accountsChanged", myHandler);

---

API Reference

Direct Method	KIP-style (kastle.request)	Returns
kastle.connect()	kas:connect	boolean
kastle.getVersion()	kas:get_version	string (e.g. 2.47.0+extension, 1.19.0+mobile)
kastle.getAccount()	kas:get_account	{ address, publicKey }
kastle.getNetwork()	kas:get_network	string
kastle.switchNetwork(networkId)	kas:switch_network	string
kastle.getBalance()	kas:get_balance	{ balance: string }
kastle.getUtxoEntries()	kas:get_utxo_entries	{ entries[] }
kastle.sendKaspa(toAddress, sompi, opts?)	kas:send_sompi	string (txId)
kastle.buildTransaction(outputs, opts?)	kas:build_transaction	{ networkId, transactions[] }
kastle.signAndBroadcastTx(networkId, txJson, scripts?)	kas:sign_and_broadcast_tx	string (txId)
kastle.signTx(networkId, txJson, scripts?)	kas:sign_tx	string (signed txJson)
kastle.signMessage(message)	kas:sign_message	string (signature)
kastle.commitReveal(networkId, namespace, data, opts?)	kas:commit_reveal	{ commitTxId, revealTxId }
kastle.compoundUtxos(opts?)	kas:compound_utxos	string (txId)

---

Full Working Example

See the interactive demo for a complete, runnable reference:

• docs/index.js — Full source code for all operations above