--- title: "Wavelength: instant, high-volume, low-fee payments for apps and AI agents" description: "Embed a self-custodial Bitcoin, Lightning, and Ark wallet in any web or mobile app. No node to run. First payment in minutes. By Lightning Labs." docs: https://wavelength.lightning.engineering/ llms: https://wavelength.lightning.engineering/llms.txt --- # Wavelength > Status: Alpha. Open to everyone on Bitcoin test networks today; mainnet access by invite (https://forms.gle/81qmjdNVJLzh2tBi9). Announcement: https://lightning.engineering/posts/2026-07-21-wavelength-launch/_ **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: https://wavelength.lightning.engineering/demo/ - Read the docs: https://wavelength.lightning.engineering/ - GitHub: https://github.com/lightninglabs/wavelength ## The story: the whole story, in five dates The internet moves information in milliseconds. Money still takes days. Cross-border payments hop through intermediary banks, settle only during banking hours, and lose a cut at every stop. 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. - **2009 · Bitcoin. The settlement layer.** Neutral, global, final, owned by no one. The most solid infrastructure that exists for moving value. - **2018 · Lightning. The speed layer.** Payments on top of Bitcoin in under a second, for fractions of a cent, at any scale. The catch: running it self-custodially meant running nodes, channels, and liquidity. - **2020 · L402. The payment language of the web.** It turns HTTP 402 Payment Required into working payments: any API can charge per request over Lightning, and any machine can pay it. https://l402.tech/ - **2023 · Taproot Assets. Stablecoins on the same rails.** Dollars moving over the same Lightning rails, with Bitcoin as the backbone. - **2026 · 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. An API, a CLI, and an MCP server let AI agents hold and use a wallet of their own (https://wavelength.lightning.engineering/agents/#add-the-wavelength-sdk-to-your-agentsmd). First payment in minutes. **Minutes** to your first payment · **0** nodes to run · **Seconds** for money to arrive · **100%** held by your users ## Try it live The actual Wavelength wallet booting in your browser as WebAssembly, on Bitcoin's signet test network: https://wavelength.lightning.engineering/demo/ ## Who needs this - **Wallets & fintech.** Your users are asking for Bitcoin payments that arrive in seconds, and you don't want to become their bank to deliver it. Drop Wavelength in without new infrastructure or custody risk. - **Apps & platforms.** Games that pay winners, marketplaces that settle globally, tips that reach the creator, remittances that cost cents. Money as one more feature instead of a second company. - **AI builders.** Agents get a wallet of their own: money they can hold, spend, and earn. Guide: https://wavelength.lightning.engineering/agents/#add-the-wavelength-sdk-to-your-agentsmd ## Why it matters - **It's truly theirs.** Like cash in their own pocket, not an IOU. No one can freeze it, lose it, or lend it out. - **It's instant.** Seconds to arrive, cents to move, any hour, any continent. - **It works everywhere.** A phone in Bogota, a laptop in Lagos, a browser tab in Berlin. No bank account required. - **There's always a way out.** The unilateral exit guarantee, below. ## "Unilateral exit," in plain words Users can always leave with their money, on their own. 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, and taking money out is usually just a regular payment to any Bitcoin address. If Wavelength's servers ever stopped answering, users could still leave without them: slower and more expensive, so it's kept for emergencies. That's the unilateral exit: one side is enough. - No permission needed: not the operator, not Lightning Labs. - Works even without us: no servers or help required. - Enforced by Bitcoin: the rules live in Bitcoin itself. Details: https://wavelength.lightning.engineering/concepts/leaving-ark/ and https://wavelength.lightning.engineering/guides/unilateral-exit/ ## Wallets for machines Fund an agent once and it pays for APIs, data, and compute over Lightning, programmatically, with no accounts and no human in the loop. It can charge for its own services and hold what it earns. Wavelength speaks L402, the open protocol for pay-per-request payments over Lightning: https://l402.tech/ Agents guide: https://wavelength.lightning.engineering/agents/#add-the-wavelength-sdk-to-your-agentsmd ## 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. More: https://wavelength.lightning.engineering/introduction/the-wavelength-system/ - **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. More: https://wavelength.lightning.engineering/concepts/leaving-ark/ - **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. More: https://wavelength.lightning.engineering/web/get-started/requirements/ - **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. More: https://wavelength.lightning.engineering/introduction/what-is-wavelength-sdk/ - **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. More: https://wavelength.lightning.engineering/web/get-started/quickstart/ Agent security: wallet creation and unlock never travel over the agent channel, so seeds are never exposed to the model. Install agent skills with one command: `npx skills add lightninglabs/wavelength-sdk` ## For engineers: the full surface - SDK overview: https://wavelength.lightning.engineering/ - Wallet API (gRPC & REST to the waved daemon): https://wavelength.lightning.engineering/api/ and https://wavelength.lightning.engineering/api/get-started/ - CLI (wavecli, structured JSON for humans and agents): https://wavelength.lightning.engineering/cli/ - Daemon status: https://wavelength.lightning.engineering/cli/getinfo/ · Machine-readable schemas: https://wavelength.lightning.engineering/cli/schema/ - MCP server (each daemon RPC as a typed tool call): https://wavelength.lightning.engineering/cli/mcp/ - Advanced: Ark protocol commands https://wavelength.lightning.engineering/cli/ark/ · vHTLC recovery https://wavelength.lightning.engineering/cli/recovery/ · raw daemon access https://wavelength.lightning.engineering/cli/dev/ ## Documentation - Overview: https://wavelength.lightning.engineering/ - System architecture: https://wavelength.lightning.engineering/introduction/system-architecture/ - Balances & VTXOs: https://wavelength.lightning.engineering/concepts/balances-and-vtxos/ - Lightning payments = swaps: https://wavelength.lightning.engineering/concepts/lightning-payments-are-swaps/ - Leaving Ark: https://wavelength.lightning.engineering/concepts/leaving-ark/ - Unilateral exit: https://wavelength.lightning.engineering/guides/unilateral-exit/ - llms.txt: https://wavelength.lightning.engineering/llms.txt Built by Lightning Labs, creators of lnd. Open source (MIT): https://github.com/lightninglabs/wavelength - Launch announcement: https://lightning.engineering/posts/2026-07-21-wavelength-launch/ - X: https://x.com/lightning — Contact: hello@lightning.engineering. Your users should never need anyone's permission to get their money back.