✨ Bitcoin TypeScript/JavaScript Library for NodeJS, Browser and Mobile ✨

_Bitcoin is hard. Especially for those not familiar with crypto, it is even hard to create a simple bitcoin transaction._

bitcoin-sdk-js provides various features which help to create various type of bitcoin transaction so easily🚀, including advanced smart contract like multisig, hashlock, timelock, combination of them, and even your own smart contract.

Legacy, Segwit, Taproot features are all suppoted!

Install

bash
npm install bitcoin-sdk-js

How To Use

• Generate Address

• Create Transaction

• Sign Message and Verify Signature - BIP322 (P2PKH, P2WPKH, P2TR)

Generate Address (P2PKH, P2WPKH, P2SH, P2WSH, P2TR)

1. Address for Single Signer(P2PKH, P2WPKH, P2TR)

javascript
import * as bitcoin from 'bitcoin-sdk-js'
// if you need to generate key pair const keyPair = await bitcoin.wallet.generateKeyPair(); // p2pkh const legacyAddress = await bitcoin.address.generateAddress(   keyPair.publicKey,   'legacy', ); // p2wpkh const segwitAddress = await bitcoin.address.generateAddress(   keyPair.publicKey,   'segwit', ); // p2tr const taprootAddress = await bitcoin.address.generateAddress(   (     // It's recommended to tweak public key to generate taproot address     await bitcoin.tapscript.getTapTweakedPubkey(       // Schnorr key is same with any bitcoin key pair, except it does not use public key prefix byte '02' or '03'.       keyPair.publicKey.slice(2),       await bitcoin.tapscript.getTapTweak(keyPair.publicKey.slice(2)),     )   ).tweakedPubKey,   'taproot', ); // p2pkh - testnet const legacyAddressTestnet = await bitcoin.address.generateAddress(   keyPair.publicKey,   'legacy',   'testnet', ); // p2wpkh - testnet const segwitAddressTestnet = await bitcoin.address.generateAddress(   keyPair.publicKey,   'segwit',   'testnet', ); // p2tr - testnet const taprootAddressTestnet = await bitcoin.address.generateAddress(   (     // It's recommended to tweak public key to generate taproot address     await bitcoin.tapscript.getTapTweakedPubkey(       // Schnorr key is same with any bitcoin key pair, except it does not use public key prefix byte '02' or '03'.       keyPair.publicKey.slice(2),       await bitcoin.tapscript.getTapTweak(keyPair.publicKey.slice(2)),     )   ).tweakedPubKey,   'taproot',   'testnet', );

2. Address for Script(P2SH, P2WSH)

javascript

import * as bitcoin from 'bitcoin-sdk-js'
// if you need to generate key pair const keyPair = await bitcoin.wallet.generateKeyPair(); // Script can be any of bitcoin script opcode! bitcoin-sdk-js provides an easy way to build script. // Below script is timelock + single sig const script =        await bitcoin.script.generateTimeLockScript(2542622) + await bitcoin.script.generateSingleSigScript(keyPair.publicKey); // p2sh const legacyScriptAddress = await bitcoin.address.generateScriptAddress(   script,   'legacy', ); // p2wsh const segwitScriptAddress = await bitcoin.address.generateScriptAddress(   script,   'segwit', ); // p2sh - testnet const legacyScriptAddressTestnet = await bitcoin.address.generateScriptAddress(   script,   'legacy',   'testnet', ); // p2wsh - testnet const segwitScriptAddressTestnet = await bitcoin.address.generateScriptAddress(   script,   'segwit',   'testnet', );

Create Transaction (P2PKH, P2WPKH, P2SH, P2WSH, P2TR)

1. Transaction for Single Signer(P2PKH, P2WPKH)

javascript

import * as bitcoin from 'bitcoin-sdk-js';
// if you need to generate key pair const keyPair = await bitcoin.wallet.generateKeyPair(); const pubkey = keyPair.publicKey; const privkey = keyPair.privateKey;
// initialize Bitcoin Transaction object const tx = new bitcoin.Transaction();
// add UTXO to spend as an input await tx.addInput({   txHash: txId, // transaction id of utxo   index: 0, // index of utxo in transaction   value: value, // value of utxo(unit is satoshi) } as bitcoin.UTXO);
// add Target output to send Bitcoin // most common transaction which sends bitcoin to single sig address await tx.addOutput({     address: await bitcoin.address.generateAddress(pubkey),     value: value - fee, // value of utxo - fee } as bitcoin.Target);
// if input utxo only requires single sig(p2wpkh or p2pkh) await tx.signInput(privkey, 0);
// You can broadcast signed tx here: https://blockstream.info/testnet/tx/push const txToBroadcast: string = await tx.getSignedHex();

2. Transaction for Multi Signer(P2SH, P2WSH)

javascript

import * as bitcoin from 'bitcoin-sdk-js';
// initialize Bitcoin Transaction object const tx = new bitcoin.Transaction();
// add UTXO to spend as an input await tx.addInput({   txHash: txId, // transaction id of utxo   index: 0, // index of utxo in transaction   value: value, // value of utxo(unit is satoshi) } as bitcoin.UTXO);
// add Target output to send Bitcoin // sends bitcoin to 2-of-3 multisig transaction await tx.addOutput({     // all the smart contract output is recommended to use script address!     address: await bitcoin.address.generateScriptAddress(         // this generate multisig smart contract, which is possible up to 15-of-15          await bitcoin.script.generateMultiSigScript(2, [pubkey1, pubkey2, pubkey3]),     ),     value: value - fee, // value of utxo - fee } as bitcoin.Target);
// if input utxo requires multi sig(p2wsh or p2sh) await tx.multiSignInput(     [pubkey1, pubkey2, pubkey3],     [privkey1, privkey2],     0, // input index to sign );
// You can broadcast signed tx here: https://blockstream.info/testnet/tx/push const txToBroadcast: string = await tx.getSignedHex();

3. Transaction for Single(or Multi) Signer with TimeLock (or || and) HashLock(P2SH, P2WSH)

javascript
import * as bitcoin from 'bitcoin-sdk-js';
// initialize Bitcoin Transaction object const tx = new bitcoin.Transaction();
// add UTXO to spend as an input await tx.addInput({   txHash: txId, // transaction id of utxo   index: 0, // index of utxo in transaction   value: value, // value of utxo(unit is satoshi) } as bitcoin.UTXO);
// add Target output to send Bitcoin // sends bitcoin to single(or multi) sig script with timelock await tx.addOutput({     address: await bitcoin.address.generateScriptAddress(         // able to spend this output after given block height         (await bitcoin.script.generateTimeLockScript(2542622)) +         // you can use generateMultiSigScript instead of single sig here         (await bitcoin.script.generateSingleSigScript(pubkey)),     ),     value: value - fee, // value of utxo - fee } as bitcoin.Target);
// sends bitcoin to single(or multi) sig script with hashlock await tx.addOutput({     address: await bitcoin.address.generateScriptAddress(         // able to spend this output if 'secretHex' is given         (await bitcoin.script.generateHashLockScript('secretHex')) +          // you can use generateMultiSigScript instead of single sig here         (await bitcoin.script.generateSingleSigScript(pubkey)),     ),     value: value - fee, // value of utxo - fee } as bitcoin.Target);
// sends bitcoin to single(or multi) sig script with timelock + hashlock await tx.addOutput({     address: await bitcoin.address.generateScriptAddress(         /*          WATCH OUT! Order matters. You must place script in the order of         timelock, hashlock and single(or multi) sig         to spend this output with bitcoin-sdk-js         */         (await bitcoin.script.generateTimeLockScript(2542622)) +         (await bitcoin.script.generateHashLockScript('secretHex')) +         // you can use generateMultiSigScript instead of single sig here         (await bitcoin.script.generateSingleSigScript(pubkey)),     ),     value: value - fee, // value of utxo - fee } as bitcoin.Target);
// if transaction use timelock input, must set tx locktime bigger than input timelock await tx.setLocktime(2542622);
// if input utxo requires single sig with smart contract(p2wsh or p2sh) await tx.signInput(     privkey,     0, // input index to sign     'segwit', // default is segwit, you might use legacy if necessary     await bitcoin.script.generateTimeLockScript(2542622), // is timelock input? provide script     'secretHex', // is hashlock input? provide secretHex to unlock );
// or if input utxo requires multi sig with smart contract(p2wsh or p2sh) await tx.multiSignInput(     [pubkey1, pubkey2, pubkey3],     [privkey1, privkey2],     0, // input index to sign     'segwit', // default is segwit, you might use legacy if necessary     await bitcoin.script.generateTimeLockScript(2542622), // is timelock input? provide script     'secretHex', // is hashlock input? provide secretHex to unlock );
// You can broadcast signed tx here: https://blockstream.info/testnet/tx/push const txToBroadcast: string = await tx.getSignedHex();

4. Transaction for TimeLock (or || and) HashLock without Signer(P2SH, P2WSH)

javascript

import * as bitcoin from 'bitcoin-sdk-js';
// initialize Bitcoin Transaction object const tx = new bitcoin.Transaction();
// add UTXO to spend as an input await tx.addInput({   txHash: txId, // transaction id of utxo   index: 0, // index of utxo in transaction   value: value, // value of utxo(unit is satoshi) } as bitcoin.UTXO);
// add Target output to send Bitcoin // sends bitcoin to script with timelock + hashlock (no sig required) await tx.addOutput({     address: await bitcoin.address.generateScriptAddress(         // if you only want hashlock, you can remove generateTimeLockScript         (await bitcoin.script.generateTimeLockScript(2542622)) +         (await bitcoin.script.generateHashLockScript('secretHex')),        ),     value: value - fee, // value of utxo - fee } as bitcoin.Target);
// if transaction use timelock input, must set tx locktime bigger than input timelock await tx.setLocktime(2542622);
// if input utxo requires to unlock hash with smart contract(p2wsh or p2sh) await tx.unlockHashInput(     'secretHex',     0,     'segwit', // default is segwit, you might use legacy if necessary     await bitcoin.script.generateTimeLockScript(2542622),// is timelock input? provide script );
// You can broadcast signed tx here: https://blockstream.info/testnet/tx/push const txToBroadcast: string = await tx.getSignedHex();

5. Custom smart contract(P2SH, P2WSH)

javascript

import * as bitcoin from 'bitcoin-sdk-js';
// You can send and spend any smart contract. Below example is classic HTLC const HTLC = bitcoin.Opcode.OP_IF +         (await bitcoin.script.generateTimeLockScript(2576085)) +         (await bitcoin.data.pushData(pubkey1)) + // must specify data to read(if not opcode)         pubkey1 +         bitcoin.Opcode.OP_ELSE +         (await bitcoin.script.generateHashLockScript('abcdef')) +         (await bitcoin.data.pushData(pubkey2)) + // must specify data to read(if not opcode)         pubkey2 +         bitcoin.Opcode.OP_ENDIF +         bitcoin.Opcode.OP_CHECKSIG // p2wsh address, custom contract address must be p2wsh(p2sh) (or taproot address, check next chapter!) const toAddress = await bitcoin.address.generateScriptAddress(HTLC);
// Then, can be spent as an input by signing by scriptSig! // initialize Bitcoin Transaction object const tx = new bitcoin.Transaction();
// if transaction use timelock input, must set tx locktime bigger than input timelock await tx.setLocktime(2576085);
// spend by executing OP_IF branch await tx.signInputByScriptSig(     // script sig list(order matters!!! bitcoin script is stack-based LIFO)     [       await bitcoin.crypto.sign(         // method to get input message hash to sign         await tx.getInputHashToSign(           HTLC, // redeem script as p2wsh           0, // input index         ),         privkey1, // signer private key       ),       '01', // execute OP_IF       HTLC, // redeem script as p2wsh     ],     0, // input index   ); // Or spend by executing OP_ELSE branch await tx.signInputByScriptSig(     // script sig list(order matters!!! bitcoin script is stack-based LIFO)     [       await bitcoin.crypto.sign(         // method to get input message hash to sign         await tx.getInputHashToSign(           HTLC, // redeem script as p2wsh           0, // input index         ),         privkey2, // signer private key       ),       'abcdef', // unlock hash       '', // execute OP_ELSE       HTLC, // redeem script as p2sh     ],     0, // input index   );
// You can broadcast signed tx here: https://blockstream.info/testnet/tx/push const txToBroadcast: string = await tx.getSignedHex();

6. Taproot and Tapscript spend(P2TR)

javascript
import * as bitcoin from 'bitcoin-sdk-js';
// Let's send and spend above HTLC in taproot and tapscript way! /*   Schnorr key is same with any bitcoin key pair, except it does not use public key prefix byte '02' or '03'.   This key pair will be used as a master key to spend UTXO in taproot, after tweaked(will explain how to step by step). */ const keyPair = await bitcoin.wallet.generateKeyPair(); const schnorrPubkey = keyPair.publicKey.slice(2); // remove first byte (which is parity bit) const schnorrPrivkey = keyPair.privateKey;
/*   HTLC consists of conditional branch, in which OPIF contains Time Lock Contract and OPELSE contains Hash Lock.   We can construct tapscript tree where each leaf has its own contract(script), enable unlimited spending branches. */ // Originally OP_IF branch Time Lock Contract const timeLockContract =     (await bitcoin.script.generateTimeLockScript(2576085)) +     (await bitcoin.data.pushData(schnorrPubkey1)) + // must specify data to read(if not opcode)     schnorrPubkey1 + // you must use schnorr key even in tapscript     bitcoin.Opcode.OP_CHECKSIG; // Originally OP_ELSE branch Hash Lock Contract const hashLockContract =     (await bitcoin.script.generateHashLockScript('abcdef')) +     (await bitcoin.data.pushData(schnorrPubkey2)) + // must specify data to read(if not opcode)     schnorrPubkey2 + // you must use schnorr key even in tapscript     bitcoin.Opcode.OP_CHECKSIG;
/*   You can get tapbranch from a pair of script, and repeat over to reach to the root of tree(which is 'taproot')    Here we have only a single pair of script, so tapbranch of it is taproot */ const taproot = await bitcoin.tapscript.getTapBranch([     await bitcoin.tapscript.getTapLeaf(timeLockContract),     await bitcoin.tapscript.getTapLeaf(hashLockContract), ]); // Then, get taptweak with schnorr key generated above const tapTweak = await bitcoin.tapscript.getTapTweak(     schnorrPubkey,     taproot, ); // Finally, you can tweak schnorr public key, which can be used as taproot key! const tapTweakedPubkey = await bitcoin.tapscript.getTapTweakedPubkey(     schnorrPubkey,     tapTweak, ); // generate taproot address with taproot key(and send to it!) const toAddress = await bitcoin.address.generateAddress(tapTweakedPubkey.tweakedPubKey, 'taproot');
// initialize Bitcoin Transaction object const tx = new bitcoin.Transaction();
await tx.setLocktime(2576085); // if transaction use timelock input, must set tx locktime bigger than input timelock
// Then, can be spent as an input! // one thing to keep in mind, taproot or tapscript spend needs to provide all the script public key of input await tx.addInput({     txHash: txId,     index: 0,     value: value,     script: await bitcoin.script.getScriptByAddress(toAddress), });
// taproot spend? just sign input with tweaked schnorr key(which is, taproot private key) await tx.signInput(     await bitcoin.tapscript.getTapTweakedPrivkey(schnorrPrivkey, tapTweak), // provide tweaked private key     0,     'taproot', );
// Or tapscript spend? Let's spend by hash lock script! const sigStack = [     await bitcoin.crypto.sign(       await tx.getInputHashToSign(hashLockContract, 0, 'tapscript'),       schnorrPrivkey2,       'schnorr',     ), // schnorr signature     'abcdef', // hash to unlock     hashLockContract, // spend script     // you must specify path to find taproot with provided script(For more detail, check BIP341!)     await bitcoin.tapscript.getTapControlBlock(       schnorrPubkey,       tapTweakedPubkey.parityBit,       await bitcoin.tapscript.getTapLeaf(timeLockContract), // path to find taproot     ), ];
await tx.signInputByScriptSig(sigStack, 0, 'tapscript');
// You can broadcast signed tx here: https://blockstream.info/testnet/tx/push const txToBroadcast: string = await tx.getSignedHex();

Sign Message and Verify Signature - BIP322 (P2PKH, P2WPKH, P2TR)

javascript
import * as bitcoin from 'bitcoin-sdk-js'
// if you need to generate key pair const keyPair = await bitcoin.wallet.generateKeyPair(); const pubkey = keyPair.publicKey; const privkey = keyPair.privateKey;
// address to verify(legacy p2pkh, segwit p2wpkh, taproot p2tr are all supported!) const legacyAddress = await bitcoin.address.generateAddress(   pubkey,   'legacy', ); const segwitAddress = await bitcoin.address.generateAddress(   pubkey,   'segwit', ); const tapAddress = await bitcoin.address.generateAddress(   (     await bitcoin.tapscript.getTapTweakedPubkey(       pubkey.slice(2),       await bitcoin.tapscript.getTapTweak(pubkey.slice(2)),     )   ).tweakedPubKey,   'taproot', ); // message to sign const msg = "message to sign"; // sign messsage with private key and address const sigLegacy = await bitcoin.crypto.signMessage(   msg,   privkey,   legacyAddress, ); const sigSegwit = await bitcoin.crypto.signMessage(   msg,   privkey,   segwitAddress, ); const sigTap = await bitcoin.crypto.signMessage(msg, privkey, tapAddress); // verify signature from address, returning boolean. await bitcoin.crypto.verifyMessage(msg, sigLegacy, legacyAddress); await bitcoin.crypto.verifyMessage(msg, sigSegwit, segwitAddress); await bitcoin.crypto.verifyMessage(msg, sigTap, tapAddress);

📜 License