Lightning Web SDK

An npm package that provides useful and common tools and helpers to build lightning web applications.

Before you start coding, look at example scenarios in our Developer Sandbox

🤖 🚀 ⚡ For Developers using Agents / LLMs / Vibe Coding

Skip the rest of this README and use the Alby Bitcoin Builder Skill to build a bitcoin app or the Alby Bitcoin Payment Skill to give your agent payment capabilities. It will handle the rest!

Manual Installation

npm install @getalby/lightning-tools

or

yarn add @getalby/lightning-tools

or for use without any build tools:

<script type="module">
  import { LightningAddress } from "https://esm.sh/@getalby/lightning-tools@7"; // jsdelivr.net, skypack.dev also work

  // use LightningAddress normally...
  (async () => {
    const ln = new LightningAddress("hello@getalby.com");
    // fetch the LNURL data
    await ln.fetch();
    // get the LNURL-pay data:
    console.log(ln.lnurlpData);
  })();
</script>

This library relies on a global fetch() function which will work in browsers and node v18 or newer. (In older versions you have to use a polyfill.)

🤙 Usage

Lightning Address

The LightningAddress class provides helpers to work with lightning addresses

import { LightningAddress } from "@getalby/lightning-tools/lnurl";

const ln = new LightningAddress("hello@getalby.com");

// fetch the LNURL data
await ln.fetch();

// get the LNURL-pay data:
console.log(ln.lnurlpData); // returns a [LNURLPayResponse](https://github.com/getAlby/js-lightning-tools/blob/master/src/types.ts#L1-L15)
// get the keysend data:
console.log(ln.keysendData);

Get an invoice:

import { LightningAddress } from "@getalby/lightning-tools/lnurl";

const ln = new LightningAddress("hello@getalby.com");

await ln.fetch();
// request an invoice for 1000 satoshis
// this returns a new `Invoice` class that can also be used to validate the payment
const invoice = await ln.requestInvoice({ satoshi: 1000 });

console.log(invoice.paymentRequest); // print the payment request
console.log(invoice.paymentHash); // print the payment hash

Verify a payment

import { LightningAddress } from "@getalby/lightning-tools/lnurl";
const ln = new LightningAddress("hello@getalby.com");
await ln.fetch();

const invoice = await ln.requestInvoice({ satoshi: 1000 });

// if the LNURL providers supports LNURL-verify:
const paid = await invoice.verifyPayment(); // returns true of false
if (paid) {
  console.log(invoice.preimage);
}

// if you have the preimage for example in a WebLN context
await window.webln.enable();
const response = await window.webln.sendPayment(invoice.paymentRequest);
const paid = invoice.validatePreimage(response.preimage); // returns true or false
if (paid) {
  console.log("paid");
}

// or use the convenient method:
await invoice.isPaid();

It is also possible to manually initialize the Invoice

import { Invoice } from "@getalby/lightning-tools/bolt11";

const invoice = new Invoice({ pr: pr, preimage: preimage });
await invoice.isPaid();

Boost a LN address:

You can also attach additional metadata information like app name, version, name of the podcast which is boosted etc. to the keysend payment.

import { LightningAddress } from "@getalby/lightning-tools/lnurl";
const ln = new LightningAddress("hello@getalby.com");
await ln.fetch();

const boost = {
  action: "boost",
  value_msat: 21000,
  value_msat_total: 21000,
  app_name: "Podcastr",
  app_version: "v2.1",
  feedId: "21",
  podcast: "random podcast",
  episode: "1",
  ts: 2121,
  name: "Satoshi",
  sender_name: "Alby",
};
await ln.boost(boost);

Zapping a LN address on Nostr:

Nostr is a simple, open protocol that enables truly censorship-resistant and global value-for-value publishing on the web. Nostr integrates deeply with Lightning. more info

This librarys provides helpers to create zaps.

import { LightningAddress } from "@getalby/lightning-tools/lnurl";
const ln = new LightningAddress("hello@getalby.com");
await ln.fetch();

const response = await ln.zap({
  satoshi: 1000,
  comment: "Awesome post",
  relays: ["wss://relay.damus.io"],
  e: "44e1827635450ebb3c5a7d12c1f8e7b2b514439ac10a67eef3d9fd9c5c68e245",
});
console.log(response.preimage); // print the preimage

For a full example see examples/zaps

Zapping a LN address on Nostr using Nostr Wallet Connect:

Native zaps without a browser extension are possible by using a Nostr Wallet Connect WebLN provider.

See examples/zaps-nwc

All examples in the examples/ directory are runnable. See examples/README.md for setup instructions.

HTTP 402 - requesting HTTP resources that require a payment

L402, X402, MPP are protocol standards based on the HTTP 402 Payment Required code for machine-to-machine payments. It is used to charge for HTTP API requests, tool calls, or agentic payments.

This library includes functions to consome those resources.

fetch402(url: string, fetchArgs, options)

fetch402 is a single function that transparently handles L402 and X402 and MPP protected resources. Use it when you don't know or don't care which protocol the server uses — it will detect the protocol from the response headers and pay accordingly.

url: the protected URL
fetchArgs: arguments are passed to the underlying fetch() function used to do the HTTP request
options:
- wallet: any object that implements payInvoice({ invoice }) and returns { preimage, fees_paid? }. Used to pay L402, X402 and MPP invoices.
- credentials (optional): a credential from a previous paid request (response.payment.credentials). When provided it is applied to the request before it is sent so the server can authorize it without a new payment — see Payment info & polling.

Examples

import { fetch402 } from "@getalby/lightning-tools/402";
import { NWCClient } from "@getalby/sdk";

const nwc = new NWCClient({
  nostrWalletConnectUrl: "nostr+walletconnect://...",
});

await fetch402("https://example.com/protected-resource", {}, { wallet: nwc })
  .then((res) => res.json())
  .then(console.log)
  .finally(() => nwc.close());

Payment info & polling

All of the 402 fetch helpers (fetch402, fetchWithL402, fetchWithX402, fetchWithMpp) return a standard fetch Response. When a payment was made (or a supplied credential was reused) the response also carries a payment property:

interface PaymentInfo {
  paid: boolean; // whether a lightning payment was made for this request
  amount: number; // amount of the paid invoice, in satoshis (0 when paid is false)
  feesPaid?: number; // routing fees in millisatoshis, when reported by the wallet
  preimage?: string; // payment preimage, when a payment was made
  credentials: {
    // reusable credential — pass back via options.credentials
    header: string; // e.g. "Authorization" (L402/MPP) or "payment-signature" (x402)
    value: string;
  };
}

This lets you inspect what a request cost, and — by passing credentials back on a follow-up request — authorize subsequent calls without paying again (e.g. polling a long-running video/song generation job).

Important: when you pass credentials, the helper reuses them and never pays a second time. If the server still responds with a 402 (e.g. the credential expired or the balance is depleted), that 402 response is returned to you as-is — the library will not silently pay another invoice. You decide what to do next: retry the same credential, or make a fresh unauthenticated request to pay again.

// First request (no credentials): pays once and returns the content plus a reusable credential
const res = await fetch402(url, { method: "POST", body }, { wallet: nwc });
const job = await res.json();
console.info(`Paid ${res.payment.amount} sats`);

// Follow-up requests reuse the credential — these NEVER pay again
const pollRes = await fetch402(
  `${url}/status/${job.id}`,
  {},
  { wallet: nwc, credentials: res.payment.credentials },
);
if (pollRes.status === 402) {
  // credential not (yet) accepted — retry the same credential later, do not re-pay
} else {
  console.info(await pollRes.json());
}

L402

L402 is a protocol standard based on the HTTP 402 Payment Required error code designed to support the use case of charging for services and authenticating users in distributed networks.

This library includes a fetchWithL402 function to consume L402 protected resources.

fetchWithL402(url: string, fetchArgs, options)

url: the L402 protected URL
fetchArgs: arguments are passed to the underlying fetch() function used to do the HTTP request
options:
- wallet: any object (e.g. a NWC client) that implements payInvoice({ invoice }) and returns { preimage, fees_paid? }. Used to pay the L402 invoice.
- credentials (optional): a credential from a previous paid request — see Payment info & polling.

Examples

import { fetchWithL402 } from "@getalby/lightning-tools/402/l402";
import { NWCClient } from "@getalby/sdk";

const nwc = new NWCClient({
  nostrWalletConnectUrl: "nostr+walletconnect://...",
});

await fetchWithL402(
  "https://l402.example.com/protected-resource",
  {},
  { wallet: nwc },
)
  .then((res) => res.json())
  .then(console.log)
  .finally(() => nwc.close());

X402

Similar to L402 X402 is an open protocol for machine-to-machine payments built on the HTTP 402 Payment Required status code. It enables APIs and resources to request payments inline, without prior registration or authentication.

This library includes a fetchWithX402 function to consume X402-protected resources that support the lightning network. (Note: X402 works also with other coins and network. This library supports X402 resources that accept Bitcoin on the lightning network)

fetchWithX402(url: string, fetchArgs, options)

url: the X402 protected URL
fetchArgs: arguments are passed to the underlying fetch() function used to do the HTTP request
options:
- wallet: any object (e.g. a NWC client) that implements payInvoice({ invoice }) and returns { preimage, fees_paid? }. Used to pay the X402 invoice.
- credentials (optional): a credential from a previous paid request — see Payment info & polling.

Examples

import { fetchWithX402 } from "@getalby/lightning-tools/402/x402";
import { NWCClient } from "@getalby/sdk";

const nwc = new NWCClient({
  nostrWalletConnectUrl: "nostr+walletconnect://...",
});

await fetchWithX402(
  "https://x402.example.com/protected-resource",
  {},
  { wallet: nwc },
)
  .then((res) => res.json())
  .then(console.log)
  .finally(() => nwc.close());

MPP

MPP is an open protocol for machine-to-machine payments built on the HTTP 402 Payment Required status code. Charge for API requests, tool calls, or content—agents and apps pay per request in the same HTTP call.

This library includes a fetchWithMpp function to consume MPP-protected resources that support the lightning network. (Note: MPP works also with other payment methods. This library supports resources that accept Bitcoin on the lightning network)

fetchWithMpp(url: string, fetchArgs, options)

url: the MPP protected URL
fetchArgs: arguments are passed to the underlying fetch() function used to do the HTTP request
options:
- wallet: any object (e.g. a NWC client) that implements payInvoice({ invoice }) and returns { preimage, fees_paid? }. Used to pay the MPP invoice.
- credentials (optional): a credential from a previous paid request — see Payment info & polling.

Examples

import { fetchWithMpp } from "@getalby/lightning-tools/402/mpp";
import { NWCClient } from "@getalby/sdk";

const nwc = new NWCClient({
  nostrWalletConnectUrl: "nostr+walletconnect://...",
});

await fetchWithMpp(
  "https://mpp.example.com/protected-resource",
  {},
  { wallet: nwc },
)
  .then((res) => res.json())
  .then(console.log)
  .finally(() => nwc.close());

Basic invoice decoding

You can initialize an Invoice to decode a payment request.

import { Invoice } from "@getalby/lightning-tools/bolt11";

const invoice = new Invoice({ pr });
const { paymentHash, satoshi, description, createdDate, expiryDate } = invoice;

If you need more details about the invoice, use a dedicated BOLT11 decoding library.

💵 Fiat conversions

Helpers to convert sats values to fiat and fiat values to sats.

getFiatCurrencies(): Promise<FiatCurrency[]>

Returns the list of available fiat currencies sorted by priority

getFiatValue(satoshi: number, currency: string): number

Returns the fiat value for a specified currency of a satoshi amount

getSatoshiValue(amount: number, currency: string): number

Returns the satoshi value for a specified amount (in the smallest denomination) and currency

getFormattedFiatValue(satoshi: number, currency: string, locale: string): string

Like getFiatValue but returns a formatted string for a given locale using JavaScript's toLocaleString

Examples

await fiat.getFiatCurrencies();
await fiat.getFiatValue({ satoshi: 2100, currency: "eur" });
await fiat.getSatoshiValue({ amount: 100, currency: "eur" }); // for 1 EUR
await fiat.getFormattedFiatValue({
  satoshi: 2100,
  currency: "usd",
  locale: "en",
});

BIP21 (`bitcoin:` URIs)

Parse BIP21 payment URIs, including the unified-QR lightning= fallback parameter.

import { parseBip21 } from "@getalby/lightning-tools";

const result = parseBip21(
  "bitcoin:bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4?amount=0.001&label=Donation&lightning=lnbc...",
);

if (result) {
  result.address; // "bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4"
  result.amount; // 0.001 (BTC)
  result.amountSats; // 100000
  result.label; // "Donation"
  result.lightning; // BOLT11 fallback, if present
  result.lno; // BOLT12 offer, if present
  result.unknownRequiredParams; // reject the URI if non-empty (BIP21 `req-*` rule)
}

parseBip21 returns null for inputs that don't start with the bitcoin: scheme. Address validation is intentionally out of scope — validate the returned address with your own check if needed.

🤖 Lightning Address Proxy

This library uses a proxy to simplify requests to lightning providers.

Many ln addresses don't support CORS, which means fetching the data directly in a browser environment will not always work.
Two requests are required to retrieve lnurlp and keysend data for a lightning address. The proxy will do these for you with a single request.

You can disable the proxy by explicitly setting the proxy to false when initializing a lightning address:

const lightningAddress = new LightningAddress("hello@getalby.com", {
  proxy: false,
});

crypto dependency

If you get an crypto is not defined in NodeJS error you have to import it first:

import * as crypto from 'crypto'; // or 'node:crypto'
globalThis.crypto = crypto as any;
//or: global.crypto = require('crypto');

fetch() dependency

This library relies on a global fetch object which will work in browsers and node v18.x or newer. In old version you can manually install a global fetch option or polyfill if needed.

For example:

import fetch from "cross-fetch"; // or "@inrupt/universal-fetch"
globalThis.fetch = fetch;

// or as a polyfill:
import "cross-fetch/polyfill";

🛠 Development

yarn install
yarn run build

Need help?

We are happy to help, please contact us or create an issue.

Twitter: @getAlby
Telegram group
support at getalby.com
bitcoin.design Discord community (find us on the #alby channel)
Read the Alby developer guide to better understand how Alby packages and APIs can be used to power your app.

License

MIT

Name		Name	Last commit message	Last commit date
Latest commit History 402 Commits
.github		.github
.husky		.husky
.vscode		.vscode
docs		docs
examples		examples
src		src
.eslintignore		.eslintignore
.eslintrc.json		.eslintrc.json
.gitignore		.gitignore
.prettierignore		.prettierignore
LICENSE		LICENSE
README.md		README.md
commitlint.config.js		commitlint.config.js
jest.config.ts		jest.config.ts
lint-staged.config.js		lint-staged.config.js
package.json		package.json
prettierrc.json		prettierrc.json
repl.js		repl.js
rollup.config.js		rollup.config.js
setupJest.ts		setupJest.ts
tsconfig.json		tsconfig.json
yarn.lock		yarn.lock

Uh oh!

Folders and files

Latest commit

History

Repository files navigation

Lightning Web SDK

🤖 🚀 ⚡ For Developers using Agents / LLMs / Vibe Coding

Manual Installation

🤙 Usage

Lightning Address

Get an invoice:

Verify a payment

Boost a LN address:

Zapping a LN address on Nostr:

Zapping a LN address on Nostr using Nostr Wallet Connect:

HTTP 402 - requesting HTTP resources that require a payment

fetch402(url: string, fetchArgs, options)

Examples

Payment info & polling

L402

fetchWithL402(url: string, fetchArgs, options)

Examples

X402

fetchWithX402(url: string, fetchArgs, options)

Examples

MPP

fetchWithMpp(url: string, fetchArgs, options)

Examples

Basic invoice decoding

💵 Fiat conversions

getFiatCurrencies(): Promise<FiatCurrency[]>

getFiatValue(satoshi: number, currency: string): number

getSatoshiValue(amount: number, currency: string): number

getFormattedFiatValue(satoshi: number, currency: string, locale: string): string

Examples

BIP21 (bitcoin: URIs)

🤖 Lightning Address Proxy

crypto dependency

fetch() dependency

🛠 Development

Need help?

License

About

Topics

Resources

License

Uh oh!

Stars

Watchers

Forks

Releases 25

Packages 0

Uh oh!

Uh oh!

Contributors

Uh oh!

Languages

BIP21 (`bitcoin:` URIs)

Packages