Signing Transactions

Bootstrap your project with Stacks.js Starters, which come with Stacks Connect pre-installed

This guide explains how to prompt users to sign transactions and broadcast them to the Stacks blockchain by implementing the connect package of Stacks.js.

Transaction signing provides a way for users execute Clarity smart contracts that are relevant to your app then handle the result as appropriate.

Users can sign transactions that exchange fungible or non-fungible tokens with upfront guarantees that help them retain control over their digital assets.

There are three types of transactions:

STX transfer
Contract deployment
Contract execution

See the public registry tutorial for a concrete example of these capabilities in practice.

Install dependency

tip

In order to utilize the latest transaction signing with the Stacks Wallet, use version 5 of the @stacks/connect NPM package.

The following dependency must be installed:

npm install @stacks/connect

Initiate session

Users must authenticate to an app before the connect package will work to prompt them for signing and broadcasting transactions to the Stacks blockchain with an authenticator such as the Leather Wallet.

See the authentication guide before proceeding to integrate the following transaction signing capabilities in cases where userSession.isUserSignedIn() returns true.

Get the user's Stacks address

After your user has authenticated with their Stacks Wallet, you can get their Stacks address from their profile.

const profile = userSession.loadUserData().profile.stxAddress;

const mainnetAddress = stxAddresses.mainnet;
// "SP2K5SJNTB6YP3VCTCBE8G35WZBPVN6TDMDJ96QAH"
const testnetAddress = stxAddresses.testnet;
// "ST2K5SJNTB6YP3VCTCBE8G35WZBPVN6TDMFEVESR6"

Prompt to transfer STX

Call the openSTXTransfer function provided by the connect package to trigger the display of a transaction signing prompt for transferring STX:

import { openSTXTransfer } from '@stacks/connect';
import { StacksTestnet } from '@stacks/network';

openSTXTransfer({
  recipient: 'ST2EB9WEQNR9P0K28D2DC352TM75YG3K0GT7V13CV',
  amount: '100',
  memo: 'Reimbursement',
  network: new StacksTestnet(), // for mainnet, `new StacksMainnet()`
  appDetails: {
    name: 'My App',
    icon: window.location.origin + '/my-app-logo.svg',
  },
  onFinish: data => {
    console.log('Stacks Transaction:', data.stacksTransaction);
    console.log('Transaction ID:', data.txId);
    console.log('Raw transaction:', data.txRaw);
  },
});

Several parameters are available for calling openSTXTransfer. Here's the exact interface for them:

interface STXTransferOptions {
  recipient: string;
  amount: string;
  memo?: string;
  network: StacksNetwork;
  fee: number | string;
  appDetails: {
    name: string;
    icon: string;
  };
  onFinish: (data: FinishedTxData) => void;
}

parameter	type	required	description
recipient	string	true	STX address for recipient of transfer
amount	string	true	Amount of microstacks (1 STX = 1,000,000 microstacks) to be transferred provided as string to prevent floating point errors.
appDetails	object	true	Dictionary that requires `name` and `icon` for app
onFinish	function	true	Callback executed by app when transaction has been signed and broadcasted.
memo	string	false	Optional memo for inclusion with transaction
network	StacksNetwork	false	Specify the network that this transaction should be completed on.
fee	number \| string	false	Optional fee amount in microstacks (1 STX = 1,000,000 microstacks) for overwriting the wallet's default fee value. Read more

Prompt to deploy smart contract

Call the openContractDeploy function provided by the connect package to trigger the display of a transaction signing prompt for deploying a smart contract:

import { openContractDeploy } from '@stacks/connect';

const codeBody = '(begin (print "hello, world"))';

openContractDeploy({
  contractName: 'my-contract-name',
  codeBody,
  appDetails: {
    name: 'My App',
    icon: window.location.origin + '/my-app-logo.svg',
  },
  onFinish: data => {
    console.log('Stacks Transaction:', data.stacksTransaction);
    console.log('Transaction ID:', data.txId);
    console.log('Raw transaction:', data.txRaw);
  },
});

Several parameters are available for calling openContractDeploy. Here's the exact interface for them:

interface ContractDeployOptions {
  codeBody: string;
  contractName: string;
  network: StacksNetwork;
  fee: number | string;
  appDetails: {
    name: string;
    icon: string;
  };
  onFinish: (data: FinishedTxData) => void;
}

parameter	type	required	description
codeBody	string	true	Clarity source code for contract
contractName	string	true	Name for contract
appDetails	object	true	Dictionary that requires `name` and `icon` for app
onFinish	function	true	Callback executed by app when transaction has been signed and broadcasted.
network	StacksNetwork	false	Specify the network that this transaction should be completed on.
fee	number \| string	false	Optional fee amount in microstacks (1 STX = 1,000,000 microstacks) for overwriting the wallet's default fee value. Read more

info

Contracts will deploy to the Stacks address of the authenticated user.

Prompt to execute contract

Call the openContractCall function provided by the connect package to trigger the display of a transaction signing prompt for executing a contract.

As an example, consider this simple Clarity contract:

(define-public
  (my-func
    (arg-uint uint)
    (arg-int int)
    (arg-buff (buff 20))
    (arg-string-ascii (string-ascii 20))
    (arg-string-utf8 (string-utf8 20))
    (arg-principal principal)
    (arg-bool bool)
  )
  (ok u0)
)

To execute this function, invoke the openContractCall method. Use the ClarityValue types from @stacks/transactions to construct properly formatted arguments.

import { openContractCall } from '@stacks/connect';
import {
  uintCV,
  intCV,
  bufferCV,
  stringAsciiCV,
  stringUtf8CV,
  standardPrincipalCV,
  trueCV,
} from '@stacks/transactions';

const functionArgs = [
  uintCV(1234),
  intCV(-234),
  bufferCV(Buffer.from('hello, world')),
  stringAsciiCV('hey-ascii'),
  stringUtf8CV('hey-utf8'),
  standardPrincipalCV('STB44HYPYAT2BB2QE513NSP81HTMYWBJP02HPGK6'),
  trueCV(),
];

const options = {
  contractAddress: 'ST22T6ZS7HVWEMZHHFK77H4GTNDTWNPQAX8WZAKHJ',
  contractName: 'my-contract',
  functionName: 'my-func',
  functionArgs,
  appDetails: {
    name: 'My App',
    icon: window.location.origin + '/my-app-logo.svg',
  },
  onFinish: data => {
    console.log('Stacks Transaction:', data.stacksTransaction);
    console.log('Transaction ID:', data.txId);
    console.log('Raw transaction:', data.txRaw);
  },
};

await openContractCall(options);

Several parameters are available for calling openContractCall. Here's the exact interface for them:

interface ContractCallOptions {
  contractAddress: string;
  functionName: string;
  contractName: string;
  functionArgs?: ClarityValue[];
  network: StacksNetwork;
  fee: number | string;
  appDetails: {
    name: string;
    icon: string;
  };
  onFinish: (data: FinishedTxData) => void;
}

| parameter | type | required | description | | --------------- | ---------------- | -------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --- | | contractAddress | string | true | Stacks address to which contract is deployed | | contractName | string | true | Name of contract to sign | | functionName | string | true | Name of function for signing / execution, which needs to be a public function. | | functionArgs | ClarityValue[] | true | Arguments for calling the function. Learn more about constructing clarity values. Defaults to []. | | appDetails | object | true | Dictionary that requires name and icon for app | | onFinish | function | true | Callback executed by app when transaction has been signed and broadcasted. | | | network | StacksNetwork | false | Specify the network that this transaction should be completed on. | | fee | number | string | false | Optional fee amount in microstacks (1 STX = 1,000,000 microstacks) for overwriting the wallet's default fee value. Read more |

Getting the signed transaction back after completion

Each transaction signing method from @stacks/connect allows you to specify an onFinish callback. This callback will be triggered after the user has successfully broadcasted their transaction. The transaction will be broadcasted, but it will be pending until it has been mined on the Stacks blockchain.

You can access some information about this transaction via the arguments passed to onFinish. Your callback will be fired with a single argument, which is an object with the following properties:

interface FinishedTxData {
  stacksTransaction: StacksTransaction;
  txRaw: string;
  txId: string;
}

The StacksTransaction type comes from the @stacks/transactions library.

The txId property can be used to provide a link to view the transaction in the explorer.

const onFinish = data => {
  const explorerTransactionUrl = 'https://explorer.hiro.so/txid/${data.txId}';
  console.log('View transaction in explorer:', explorerTransactionUrl);
};

Specifying the network for a transaction

All of the methods included on this page accept a network option. By default, Connect uses a testnet network option. You can import a network configuration from the @stacks/network package.

import { StacksTestnet, StacksMainnet } from '@stacks/network';

const testnet = new StacksTestnet();
const mainnet = new StacksMainnet();

// use this in your transaction signing methods:

openSTXTransfer({
  network: mainnet,
  // other relevant options
});

Usage in React Apps

Import the useConnect from the connect-react package to integrate transaction signing more seamlessly into React apps.

npm install @stacks/connect-react

Each transaction signing method is itself available as a function returned by useConnect though prefixed with do for consistency with React action naming standards:

openContractCall as doContractCall
openSTXTransfer as doSTXTransfer
openContractDeploy as doContractDeploy

Use these functions with the same parameters as outlined above. However, you don't have to specify appDetails since they are detected automatically if useConnect has been used already for authentication.

import { useConnect } from '@stacks/connect-react';

const MyComponent = () => {
  const { doContractCall } = useConnect();

  const onClick = async () => {
    const options = {
      /** See examples above */
    };
    await doContractCall(options);
  };

  return <span onClick={onClick}>Call my contract</span>;
};

Request testnet STX from faucet

You may find it useful to request testnet STX from the Explorer sandbox while developing your app with the Stacks testnet.

Transaction request / response payload

Under the hood, @stacks/connect will serialize and deserialize data between your app and the Stacks Wallet.

These payloads are tokens that conform to the JSON Web Token (JWT) standard with additional support for the secp256k1 curve used by Bitcoin and many other cryptocurrencies.

Transaction Request Payload

When an application triggers an transaction from @stacks/connect, the options of that transaction are serialized into a transactionRequest payload. The transactionRequest is similar to the authRequest payload used for authentication.

The transaction request payload has the following schema, in addition to the standard JWT required fields:

interface TransactionRequest {
  appDetails?: {
    name: string;
    icon: string;
  };
  // 1 = "allow", 2 = "deny".
  postConditionMode?: PostConditionMode; // number
  // Serialized version of post conditions
  postConditions?: string[];
  // JSON serialized version of `StacksNetwork`
  // This allows the app to specify their default desired network.
  // The user may switch networks before broadcasting their transaction.
  network?: {
    coreApiUrl: string;
    chainID: ChainID; // number
  };
  // `AnchorMode` defined in `@stacks/transactions`
  anchorMode?: AnchorMode; // number
  // The desired default stacks address to sign with.
  // There is no guarantee that the transaction is signed with this address;
  stxAddress?: string;
  txType: TransactionDetails; // see below
}

export enum TransactionTypes {
  ContractCall = 'contract_call',
  ContractDeploy = 'smart_contract',
  STXTransfer = 'token_transfer',
}

interface ContractCallPayload extends TransactionRequest {
  contractAddress: string;
  contractName: string;
  functionName: string;
  // Serialized Clarity values to be used as arguments in the contract call
  functionArgs: string[];
  txType: TransactionTypes.ContractCall;
}

interface ContractDeployPayload extends TransactinRequest {
  contractName: string;
  // raw source code for this contract
  codeBody: string;
  txType: TransactionTypes.ContractDeploy;
}

interface StxTransferPayload extends TransactionRequest {
  recipient: string;
  // amount for this transaction, in microstacks
  amount: string;
  memo?: string;
  txType: TransactionTypes.STXTransfer;
}

Transaction Response payload

After the user signs and broadcasts a transaction, a transactionResponse payload is sent back to your app.

interface TransactionResponse {
  txId: string;
  // hex serialized version of this transaction
  txRaw: string;
}

StacksProvider injected variable

When users have the Leather wallet browser extension installed, the extension will inject a global StacksProvider variable into the JavaScript context of your web app. This allows your JavaScript code to hook into the extension, and make authentication and transaction requests. @stacks/connect automatically detects and uses this global variable for you.

At the moment, only the Stacks Wallet for Web browser extension includes a StacksProvider, however, ideally more wallets (and mobile wallets) support this format, so that your app can be compatible with any Stacks Wallet that has functionality to embed web applications.

In your web application, you can check to see if the user has a compatible wallet installed by checking for the presence of window.StacksProvider.

Here is the interface for the StacksProvider variable.

interface StacksProvider {
  /**
   * Make a transaction request
   *
   * @param payload - a JSON web token representing a transaction request
   */
  transactionRequest(payload: string): Promise<TransactionResponse>;
  /**
   * Make an authentication request
   *
   * @param payload - a JSON web token representing an auth request
   *
   * @returns an authResponse string in the form of a JSON web token
   */
  authenticationRequest(payload: string): Promise<string>;
  getProductInfo:
    | undefined
    | (() => {
        version: string;
        name: string;
        meta?: {
          tag?: string;
          commit?: string;
          [key: string]: any;
        };
        [key: string]: any;
      });
}

Install dependency​

Initiate session​

Get the user's Stacks address​

Prompt to transfer STX​

Prompt to deploy smart contract​

Prompt to execute contract​

Getting the signed transaction back after completion​

Specifying the network for a transaction​

Usage in React Apps​

Request testnet STX from faucet​

Transaction request / response payload​

Transaction Request Payload​

Transaction Response payload​

StacksProvider injected variable​