Documents › Wallet Operations › Melt

Melt

1) Basic BOLT11 melt

// given a bolt11 meltQuote...
const { quote, change } = await wallet.ops.meltBolt11(meltQuote, myProofs).run();
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• Pays the Lightning invoice in the meltQuote using myProofs
• Any change is returned using wallet policy defaults.

2) BOLT12 melt with deterministic change + callback

// given a bolt12 meltQuote...
const { quote, change } = await wallet.ops
  .meltBolt12(meltQuote, myProofs)
  .asDeterministic() // counter=0 => auto-reserve
  .onCountersReserved((info) => console.log('Reserved', info))
  .run();
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• Supports async completion with NUT-08 blanks.
• Change outputs are deterministic.
• Callback hooks let you persist state for retry later.
• If you prefer global subscriptions, use:
  • onCountersReserved -> wallet.on.countersReserved()

3) Two-step melt with prepare()

const preview = await wallet.ops.meltBolt11(meltQuote, myProofs).asDeterministic().prepare();

// Persist `preview` if you want to retry safely later.
const { quote, change } = await wallet.completeMelt(preview);
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• prepare() creates the MeltPreview and any NUT-08 blanks without paying yet.
• run() is equivalent to const preview = await prepare(); await wallet.completeMelt(preview).
• This pairs well with NUT-19 cached-response retries on mints that advertise the melt endpoint.

4) Async melt with later change recovery (NUT-06 prefer_async)

For mints that support NUT-06 async melts, .prepare() pairs with OutputData.serialize to persist the change-output blanks while the payment is in flight, and wallet.createMeltChangeProofs reconstructs change proofs once the quote is paid.

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

const preview = await wallet.ops.meltBolt11(meltQuote, myProofs).asDeterministic().prepare();
const stored = JSON.stringify(preview.outputData.map((o) => OutputData.serialize(o)));
await wallet.completeMelt(preview, undefined, true); // preferAsync = true

// ... later, once the quote is paid ...
const restored = (JSON.parse(stored) as SerializedOutputData[]).map((s) =>
  OutputData.deserialize(s),
);
const change = wallet.createMeltChangeProofs(restored, paidQuote.change ?? []);
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• See Melt Token § 3 — Async melt with later change recovery for the full annotated lifecycle using the low-level wallet methods directly.

Custom payment methods

For custom payment methods (e.g., BACS, SWIFT), use the generic wallet methods directly: wallet.createMeltQuote(method, ...), wallet.checkMeltQuote(method, ...), wallet.meltProofs(method, ...), or the two-step wallet.prepareMelt(method, ...) / wallet.completeMelt(...). See Melt Token – Custom Methods for examples.