AI agents pay for any API with Bitcoin Lightning — no keys, no accounts, no monthly bills.
AI agents are the fastest-growing class of internet users — but they can't pay for anything. No bank account, no credit card, no KYC. Every API requires a human to sign up, generate a key, and manage billing.
Daemon implements the L402 protocol to turn HTTP 402 Payment Required into a real payment flow. An agent sends satoshis over Lightning, and gets data back. Zero config.
Agent Request ──→ HTTP 402 + Invoice ──→ Lightning Payment ──→ HTTP 200 OK
"Pay 1 sat" ~50ms settlement "Here's your data"
# Clone and run the interactive demo
git clone https://github.com/anthropics/daemon && cd daemon
cd gateway && npm install && npm run dev
# In another terminal — watch the full L402 handshake
.\scripts\demo-l402.ps1 # WindowsThe demo shows the complete flow: Request → 402 → Pay → 200 in under 3 seconds.
For API providers: Daemon's L402 Proxy wraps any existing HTTP API with pay-per-call micropayments — no code changes required.
# Turn any API into a paid API
UPSTREAM_URL=https://your-api.com npx @daemon/l402-proxy
# That's it. Agents now pay 1 sat per call to access your API.
# curl http://localhost:8402/your-endpoint → 402 Payment RequiredNo Stripe. No billing dashboard. No user accounts to manage. Just point the proxy at your API and start earning sats.
| You are... | How you use Daemon |
|---|---|
| API provider | Deploy L402 Proxy in front of your API → earn sats per call |
| Agent developer | Use Python/TS SDK → your agent auto-pays on 402 |
| Framework author | Integrate Eliza Plugin or MCP SDK → L402 built into your stack |
| Daemon (L402 + Lightning) | x402 (Coinbase) | Traditional API Keys | |
|---|---|---|---|
| Identity required | None | Coinbase account | Email + KYC |
| Settlement | ~50ms (Lightning) | Minutes (on-chain) | 30-day invoice |
| Minimum payment | 1 satoshi (~$0.001) | Gas fees apply | Monthly minimum |
| Machine-native | Yes — no human in the loop | Custodial wallet | Human signs up |
| Censorship risk | Permissionless | Coinbase can freeze | Provider can revoke |
L402 is the HTTP-native payment protocol. It uses the 402 Payment Required status code that HTTP reserved since 1997 — finally giving it a real implementation with Bitcoin Lightning.
┌──────────┐ ┌───────────────┐ ┌──────────┐
│ AI Agent │ ──(1)──→│ L402 Gateway │──(2)───→│ Service │
│ │ │ │ │ │
│ │←─(3)────│ 402 + Invoice │ │ │
│ │ │ + Macaroon │ │ │
│ │ └───────────────┘ │ │
│ │ │ │
│ │──(4)──→ Lightning Network ─────→ │ │
│ │←─(5)── Preimage (proof) │ │
│ │ │ │
│ │──(6)──→ L402 Token ──────────────→│ │
│ │←─(7)────────────── 200 OK ────────│ │
└──────────┘ └──────────┘
- Agent requests a protected endpoint
- Gateway returns
402with a Lightning invoice and a Macaroon - Agent pays the invoice (~1 sat, ~50ms)
- Agent gets a preimage (cryptographic proof of payment)
- Agent constructs an L402 token (Macaroon + Preimage)
- Gateway verifies the token and serves the response
Daemon is designed for human-supervised autonomy — agents act freely within guardrails set by operators.
| Control | Description |
|---|---|
| Budget Rails | Hard spending caps per agent. Agents cannot exceed the budget. |
| Allowlist | Whitelist of permitted services. Unknown endpoints are blocked. |
| Circuit Breakers | Auto-halt on anomalies (consecutive failures, unusual patterns). |
| Replay Protection | Each payment proof is single-use. Replay attacks are rejected. |
| Rate Limiting | Per-client sliding window with Redis-backed distributed state. |
| Root Key Rotation | Macaroon signing keys rotate automatically; old tokens honored during grace period. |
daemon/
├─ gateway/ # L402 Payment Gateway (Express + TypeScript)
│ ├─ middlewares/ # L402, Circuit Breaker, Replay, Rate Limit, Allowlist
│ ├─ controllers/ # LND invoice generation
│ └─ utils/ # Macaroon service, Root Key rotation, Redis
├─ agent/ # AI Agent client (Python)
│ ├─ client/ # L402 HTTP client (auto-pay on 402)
│ └─ wallet/ # LND wallet wrapper + rate limiter + alerts
├─ sdk/
│ ├─ python/ # Python SDK — pip install daemon-l402
│ ├─ ts/ # TypeScript SDK — npm install @daemon/sdk
│ └─ mcp/ # Model Context Protocol SDK
├─ plugins/
│ └─ eliza/ # ElizaOS plugin for agent frameworks
├─ proxy/ # Drop-in HTTP proxy (zero-code L402)
├─ dashboard/ # Fleet Observer (Next.js real-time UI)
└─ docker-compose.yml # Full stack: LND + Bitcoin + Gateway + Agent + DB
| Layer | Technology | Role |
|---|---|---|
| Settlement | Bitcoin (Regtest / Signet / Mainnet) | Base layer |
| Payment | LND (Lightning Network Daemon) | Instant micropayments |
| Protocol | L402 (Macaroon + Lightning) | Auth-payment fusion |
| Gateway | Express + TypeScript | API gateway with L402 middleware |
| Agent | Python + httpx | Auto-paying HTTP client |
| Dashboard | Next.js + React | Real-time fleet monitoring |
| Infra | Docker Compose, PostgreSQL, Redis | Production-ready stack |
Python
from daemon_l402 import L402Client
async with L402Client(lnd_client) as client:
response = await client.get("https://api.example.com/data") # auto-pays on 402TypeScript
import { L402Client } from '@daemon/sdk';
const client = new L402Client({ lndConnect: process.env.LND_CONNECT });
const res = await client.fetch('https://api.example.com/data'); // auto-pays on 402- L402 Protocol Spec — Lightning Labs
- LND — Lightning Network Daemon
- HTTP 402 — The status code reserved for digital payments since 1997
MIT
Daemon — The Payment Rail for the Machine Economy
Built on Bitcoin for Build on Bitcoin Hackathon (Yale Blockchain Club)
