lnget is Lightning Labs' official CLI for L402 APIs — handles request, payment, and authentication in a single command. Install: go install github.com/lightninglabs/lnget/cmd/lnget@latest

Copy and paste any of these examples:

lnget -X POST https://sats4ai.com/api/l402/generate-image \
  -d '{"prompt":"A cat on the moon"}'

lnget -X POST https://sats4ai.com/api/l402/generate-text \
  -d '{"input":[{"role":"user","content":"Explain Bitcoin"}]}'

lnget -X POST https://sats4ai.com/api/l402/transcribe-audio \
  -d '{"file":"<base64-audio>","type":"transcription"}'

lnget auto-pays the Lightning invoice, caches the token, and returns the result. Our tokens are bound to one service and one quantity and expire in 10 minutes; when a cached token is rejected, lnget pays the fresh invoice on its own — one extra round-trip, never a failure.

Spend cap. lnget refuses any invoice above 1,000 sats by default (exactly 1,000 passes) and any routing fee above 10 sats. The refusal happens on your side after the 402, so we never see it. For a dearer service pass --max-cost <sats> (or lnget config set l402.max_cost_sats <sats>). Above the default today: clone-voice (7,500 sats), generate-3d-model (1,600 sats); and every metered service — audiobook, video, TTS, calls, fax — can exceed it depending on the input, so quote first with /api/estimate-cost and set the cap from the quote.

L402 tokens expire after 10 minutes — pay the invoice and submit your request within that window. Media URLs (images, video, audio) expire after 2 hours. Download or display them promptly.

Building autonomous agents? CLW is a Bitcoin wallet built for AI agents — lets them receive, hold, and spend sats programmatically.

These open-source libraries handle L402 payment automatically — your code makes a normal HTTP request, the library detects the 402 challenge, pays the invoice, and retries with proof. No payment logic needed.

import { get } from 'l402-requests';

// That's it. The library pays the Lightning invoice automatically.
const response = await get("https://sats4ai.com/api/l402/generate-text", {
  method: "POST",
  body: JSON.stringify({ input: [{ role: "user", content: "Explain Bitcoin" }] })
});