Documents › Usage Examples › Create Wallet

Create a wallet

There are a number of ways to instantiate a wallet, depending on your needs.

Wallet classes are mostly stateless, so you can instantiate and throw them away as needed. Your app must therefore manage state, such as fetching and storing proofs in a database.

NB: You must always call loadMint() or loadMintFromCache after instantiating a wallet.

import { Wallet } from '@cashu/cashu-ts';

// Simplest: With a mint URL
const mintUrl = 'http://localhost:3338';
const wallet1 = new Wallet(mintUrl); // unit is 'sat'
await wallet1.loadMint(); // wallet is now ready to use

// Persist these in your app
const keychainCache = wallet1.keyChain.cache; // KeyChainCache
const mintInfoCache = wallet1.getMintInfo().cache; // GetInfoResponse

// Advanced: With cached mint data (avoids network calls on startup)
const wallet2 = new Wallet(keychainCache.mintUrl); // unit defaults to 'sat'
wallet2.loadMintFromCache(mintInfoCache, keychainCache);
// wallet2 is now ready to use
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Custom output generation

Pass outputDataCreator when you need to replace the default output generation logic, for example to use a platform specific implementation for deterministic secrets.

OutputDataCreator is the injectable strategy interface used by Wallet. The canonical default creation surface remains OutputData.create*(), so custom creators can delegate back to it for the standard random and P2PK behavior.

import { OutputData, type OutputDataCreator, Wallet } from '@cashu/cashu-ts';

class CustomOutputDataCreator implements OutputDataCreator {
  createP2PKData(...args: Parameters<OutputDataCreator['createP2PKData']>) {
    const [p2pk, amount, keyset, customSplit] = args;
    return OutputData.createP2PKData(p2pk, amount, keyset, customSplit);
  }

  createSingleP2PKData(...args: Parameters<OutputDataCreator['createSingleP2PKData']>) {
    const [p2pk, amount, keysetId] = args;
    return OutputData.createSingleP2PKData(p2pk, amount, keysetId);
  }

  createRandomData(...args: Parameters<OutputDataCreator['createRandomData']>) {
    const [amount, keyset, customSplit] = args;
    return OutputData.createRandomData(amount, keyset, customSplit);
  }

  createSingleRandomData(...args: Parameters<OutputDataCreator['createSingleRandomData']>) {
    const [amount, keysetId] = args;
    return OutputData.createSingleRandomData(amount, keysetId);
  }

  createDeterministicData(...args: Parameters<OutputDataCreator['createDeterministicData']>) {
    const [amount, seed, counter, keyset, customSplit] = args;
    // Replace this with your runtime-specific implementation.
    return OutputData.createDeterministicData(amount, seed, counter, keyset, customSplit);
  }

  createSingleDeterministicData(
    ...args: Parameters<OutputDataCreator['createSingleDeterministicData']>
  ) {
    const [amount, seed, counter, keysetId] = args;
    // Replace this with your runtime-specific implementation.
    return OutputData.createSingleDeterministicData(amount, seed, counter, keysetId);
  }
}

const wallet = new Wallet('http://localhost:3338', {
  outputDataCreator: new CustomOutputDataCreator(),
});
await wallet.loadMint();
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