USDT to Lightning

This guide is about buying BTC using USDT and receive it via Lightning.

Swap USDT to Lightning

Follow these steps to complete a test swap from USDC (Polygon) to BTC (Lightning) First create a new client

const client = await Client.builder()
  .withSignerStorage(new InMemoryWalletStorage())
  .withSwapStorage(new InMemorySwapStorage())
  .withOrgCode(process.env.ORG_CODE || "")
  .build();

You can find all available tokens to swap like this. For this example, we look for the token details for USDC on Polygon.

// Source token is specified directly via Asset enum
// e.g. Asset.USDT_POLYGON, Asset.USDC_POLYGON, etc.

Afterward we can create the swap request:

We only support invoices with amounts. However, you can provide an LNURL instead and we will fetch an invoice based on source or target amount.

const result = await client.createSwap({
  source: Asset.USDT_POLYGON,
  target: Asset.BTC_LIGHTNING,
  targetAddress: lightningInvoice,
});

const { response } = result;

Next, create the swap by funding the contract.

// Build an EvmSigner from your wallet (wagmi/viem example):
//
// import { createPublicClient, http } from "viem";
// const publicClient = createPublicClient({ chain, transport: http() });
// const signer: EvmSigner = {
//   address: walletClient.account.address,
//   chainId: chain.id,
//   signTypedData: (td) => walletClient.signTypedData({ ...td, account: walletClient.account }),
//   sendTransaction: (tx) => walletClient.sendTransaction({ to: tx.to, data: tx.data, chain, gas: tx.gas }),
//   waitForReceipt: (h) => publicClient.waitForTransactionReceipt({ hash: h }).then((r) => ({ status: r.status, blockNumber: r.blockNumber, transactionHash: r.transactionHash, logs: r.logs })),
//   getTransaction: (h) => publicClient.getTransaction({ hash: h }).then((tx) => ({ to: tx.to ?? null, input: tx.input, from: tx.from })),
//   call: (tx) => publicClient.call({ to: tx.to, data: tx.data, account: tx.from, blockNumber: tx.blockNumber }).then((r) => r.data ?? "0x"),
// };

declare const signer: EvmSigner; // your wallet - see EvmSigner docs

// fundSwap handles everything: allowance check, ERC-20 approval,
// Permit2 EIP-712 signing, and transaction submission.
const { txHash } = await client.fundSwap(response.id, signer);
console.log("Funded! TX:", txHash);

Wait for the status to become ServerFunded. The lightning invoice will settle automatically. You can either poll or use real-time WebSocket updates:

WebSocket (recommended)
Polling

const unsubscribe = client.subscribeToSwaps([response.id], (swapId, status) => {
  console.log("Status:", status);
  if (status === "serverfunded") {
    console.log("Swap complete! Lightning invoice settled.");
    unsubscribe();
  }
});

let swap = await client.getSwap(response.id);
while (swap.status !== "serverfunded" && swap.status !== "expired") {
  await new Promise((r) => setTimeout(r, 3000));
  swap = await client.getSwap(response.id);
}

Build with AI

We have generated a llms-full.txt file that converts all our documentation into a single markdown document following the llmstxt.org standard. Feed it to any AI coding agent (Claude, Cursor, Copilot, etc.) and it will have everything it needs to integrate the Satora Swaps SDK into your project.

Full example

/**
* USDT on Polygon → Lightning: end-to-end example (non-gasless).
*
* The user submits the funding transaction via `fundSwap`.
*/

import {
Asset,
Client,
type EvmSigner,
InMemorySwapStorage,
InMemoryWalletStorage,
} from "../src";

// #region evm-to-lightning-setup
const client = await Client.builder()
.withSignerStorage(new InMemoryWalletStorage())
.withSwapStorage(new InMemorySwapStorage())
.withOrgCode(process.env.ORG_CODE || "")
.build();
// #endregion evm-to-lightning-setup

const lightningInvoice = "lnbc1m1p..."; // Your BOLT11 invoice

// #region create-swap
const result = await client.createSwap({
source: Asset.USDT_POLYGON,
target: Asset.BTC_LIGHTNING,
targetAddress: lightningInvoice,
});

const { response } = result;
// #endregion create-swap

if (!("evm_htlc_address" in response)) {
throw new Error("Expected EVM-to-Lightning swap response");
}

console.log("Swap ID:", response.id);
// ... "550e8400-e29b-41d4-a716-446655440000"
console.log("Source amount:", response.source_amount);

// #region fund-swap
// Build an EvmSigner from your wallet (wagmi/viem example):
//
// import { createPublicClient, http } from "viem";
// const publicClient = createPublicClient({ chain, transport: http() });
// const signer: EvmSigner = {
// address: walletClient.account.address,
// chainId: chain.id,
// signTypedData: (td) => walletClient.signTypedData({ ...td, account: walletClient.account }),
// sendTransaction: (tx) => walletClient.sendTransaction({ to: tx.to, data: tx.data, chain, gas: tx.gas }),
// waitForReceipt: (h) => publicClient.waitForTransactionReceipt({ hash: h }).then((r) => ({ status: r.status, blockNumber: r.blockNumber, transactionHash: r.transactionHash, logs: r.logs })),
// getTransaction: (h) => publicClient.getTransaction({ hash: h }).then((tx) => ({ to: tx.to ?? null, input: tx.input, from: tx.from })),
// call: (tx) => publicClient.call({ to: tx.to, data: tx.data, account: tx.from, blockNumber: tx.blockNumber }).then((r) => r.data ?? "0x"),
// };

declare const signer: EvmSigner; // your wallet - see EvmSigner docs

// fundSwap handles everything: allowance check, ERC-20 approval,
// Permit2 EIP-712 signing, and transaction submission.
const { txHash } = await client.fundSwap(response.id, signer);
console.log("Funded! TX:", txHash);
// #endregion fund-swap

// #region poll-status
let swap = await client.getSwap(response.id);
while (swap.status !== "serverfunded" && swap.status !== "expired") {
await new Promise((r) => setTimeout(r, 3000));
swap = await client.getSwap(response.id);
console.log("Status:", swap.status);
// ... "pending" → "clientfunded" → "serverfunded"
}
// #endregion poll-status

if (swap.status === "expired") {
throw new Error("Swap expired - deposit was not completed in time.");
}

// #region verify-complete
const finalSwap = await client.getSwap(response.id);
console.log("Final status:", finalSwap.status);
// ... "clientredeemed"
console.log("Source:", finalSwap.source_amount, "USDT");
console.log("Target:", finalSwap.target_amount, "sats");
// ... "Target: 100000 sats"
// #endregion verify-complete

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Swap USDT to Lightning

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​Swap USDT to Lightning

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Swap USDT to Lightning

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