Instant, high-volume, low-fee payments for your app, your users, and your agents.

Adding payments to an app used to mean building infrastructure. Now it takes an API call, for people and machines alike. AI agents can even hold and spend from wallets of their own. No node to run. No custodian. Your first payment in minutes.

Try it live Read the quickstart
Don't take our word for it. Ask your AI about Wavelength.
Claude ChatGPT Perplexity Grok Gemini
See the prompt your AI will get

I'm building a product and want to evaluate Wavelength (https://wavelength.lightning.engineering/). Wavelength is a self-custodial Bitcoin wallet SDK by Lightning Labs: it embeds a full wallet inside any app (in the browser via WebAssembly, on mobile via React Native), unifies on-chain Bitcoin, Lightning, and Ark behind one balance, and needs no Lightning node, channels, or liquidity management. It sits on the Lightning Labs stack alongside L402 pay-per-request payments and Taproot Assets stablecoin rails, and it's built for the agentic economy, where AI agents hold, spend, and earn money of their own. Read the documentation at that URL, point me to the live demo at https://wavelength.lightning.engineering/demo/, and explain what Wavelength could do for my product, with concrete examples of what I could build with it.

The story

The internet moves information in milliseconds. Money still takes days.

A payment that crosses a border still hops through intermediary banks, settles only during banking hours, and loses a cut at every stop. And in most apps that handle money, a company holds the funds. The user holds a promise. The technology already existed. What was missing was putting it together. Here's how the pieces arrived.

Bitcoin

The settlement layer

Neutral, global, final, owned by no one. The most solid infrastructure that exists for moving value: no bank required, no country left out, and no one who can rewrite the rules.

Lightning

The speed layer

Payments on top of Bitcoin that arrive in under a second and cost fractions of a cent, at any scale. The catch: running it self-custodially meant running nodes, channels, and liquidity. Serious infrastructure work.

L402

The payment language of the web

It turns HTTP's dormant 402 Payment Required status code into working payments: any API can charge per request over Lightning, and any machine can pay it. l402.tech

Taproot Assets

Stablecoins on the same rails

Dollars moving over the same Lightning rails, with Bitcoin as the backbone. One set of rails, every kind of money.

Wavelength_

One SDK, for apps and agents

A self-custodial Bitcoin, Lightning, and Ark wallet that embeds in your web or mobile app. Users hold their own keys on their own devices. No node to run, no channels to manage, no liquidity to source. And it speaks to machines too: an API, a CLI, and an MCP server let AI agents hold and use a wallet of their own. First payment in minutes.

~5 min
To your first payment
0
Nodes to run
Seconds
For money to arrive
100%
Held by your users
Try it live

Don't imagine it. Open it.

The demo is the real Wavelength wallet, running in your browser as WebAssembly. Nothing to install, no account needed. It runs on Bitcoin's signet test network, so the coins are for testing, but the wallet is real. Create a wallet, grab an address, receive test sats, send a payment.

●wavelength.lightning.engineering/demo
Launch the live demo →

Signet test network. No real money involved.

Built by Lightning Labs, the creators of lnd, which has powered instant Bitcoin payments since 2018. Open source on GitHub under the MIT license.

Who needs this

Three kinds of builders. One missing piece.

Wavelength was built for the people who kept hitting the same wall from different directions.

Wallets & fintech

You have the users. They want instant Bitcoin.

Your users already trust your app. They're asking for Bitcoin payments that arrive in seconds, and you don't want to become their bank to deliver them. Add Wavelength, and your existing wallet can send and receive instant Bitcoin payments without new infrastructure or custody risk.

Apps & platforms

You have a product. Money should be a feature.

A game that pays winners. A marketplace that settles globally. A creator platform where tips actually reach the creator. Remittances that cost cents. If your product touches money across borders, Wavelength makes it one more feature instead of a second company.

AI builders

You have agents. They need money of their own.

Your agents can already think and act. But every time they need to pay for something, a human has to step in with a credit card. Wavelength gives each agent its own wallet: money it can hold, spend, and earn on its own. Add the SDK to your agents

Why it matters

What your users will actually feel.

Nobody downloads an app for its architecture. They stay because of how it treats them, and how it treats their money.

It's truly theirs.

Their money is like cash in their own pocket, not a number in a database, not an IOU from a company. No one can freeze it, lose it, or lend it out behind their back.

It's instant.

Payments arrive in seconds and cost cents, at 2 p.m. or 2 a.m., to the next room or another continent. Money finally moves at the speed of the internet.

It works everywhere.

The same wallet runs on a phone in Bogotá, a laptop in Lagos, a browser tab in Berlin. No bank account required, no country left out.

There's always a way out.

The guarantee that makes everything else honest: users can always pull their money back on their own, no matter what happens to any company involved. It has a name, the unilateral exit, and it deserves its own explanation. What that means, in plain words

The exit guarantee

“Unilateral exit,” in plain words.

Users can always leave with their money, on their own. Everything else rests on that promise.

Most money apps work like a coat check. You hand over your coat, get a ticket, and hope the counter is open when you come back.

Wavelength never takes the coat.

Users keep their own keys on their own devices. Taking money out is usually just a regular payment to any Bitcoin address.

And if Wavelength's servers ever stopped answering, users could still leave without them. It's slower and costs more, so it's kept for emergencies. That's the unilateral exit: one side is enough.

No permission needed

Nobody has to approve it: not the operator, not Lightning Labs.

Works even without us

It doesn't need our servers to be up, or our help.

Enforced by Bitcoin

The rules live in Bitcoin itself, not in a terms-of-service page.

How leaving works, in detail
The agentic economy

Meet an agent with its own money.

AI agents can already research, write, negotiate, and build. The one thing they couldn't do was pay their own way. Here's what changes when they can. The agents guide

You fund it once. Ten dollars in Bitcoin, sent to the agent's own wallet. That balance is the agent's, not an entry in anyone's database.

It pays as it works. A fraction of a cent for a weather feed. A few cents for premium data. No credit card, no signup form, no human clicking “approve” at 3 a.m.

It earns on its own. The agent sells what it makes (reports, forecasts, translations), and other agents and people pay it the same way: machine to machine, second by second.

At the end of the month, it's in the black. It earned more than it spent, holds a real balance, and never once needed a bank, an account, or a person in the loop.

Software that pays for what it uses and charges for what it makes. That's the economy Wavelength was built for.

And the keys stay out of reach: wallet creation and unlock never travel over the agent channel, so seeds are never exposed to the model. The agent can spend from its wallet. It can never take the keys.

npx skills add lightninglabs/wavelength-sdk One command wires Wavelength skills into Claude Code, Cursor, Codex, and more.

Wavelength speaks L402, the open protocol that lets any API charge per request over Lightning, and lets any agent pay it automatically. An agent with a Wavelength wallet can hit an L402-gated service, settle the invoice in seconds, and get to work. The payment language of the machine web, built by the same team. Explore the L402 protocol

Give your agent a wallet
FAQ

Common questions.

What makes Wavelength self-custodial?

The keys to the money are created on the user's own device and never leave it. No company account holds the funds, so no one can freeze, lose, or lend them out.

How Wavelength works

How do users take their money with them?

Just like any other payment: they send it to any Bitcoin address, whenever they want. And if Wavelength's servers ever stopped answering, users could still leave on their own through the unilateral exit.

Ways to leave, explained

Do I need to run any infrastructure?

No. There's no node to run, no channels to open, and no liquidity to manage. You add the SDK to your app, and Wavelength takes care of the rest.

What your app needs

Which platforms does Wavelength support?

Web browsers, iOS, and Android, through React Native or native mobile SDKs. For servers and AI agents, there's also an API, a command-line tool, and an MCP server.

Platforms and packages

How quickly can I try it?

Right now. The live demo runs in your browser with nothing to install. Developers can reach a first payment in about five minutes with the quickstart. Mainnet access is by invite.

Open the quickstart

Ready when you are.

Whether you ship apps, run a wallet, or build agents, the missing piece is now a feature you can add this week.

Start building Request mainnet access View on GitHub

Engineer on the team? The technical docs cover the architecture end to end.

SDK API wavecli waved daemon getinfo schema MCP server ark · advanced recovery dev