Entropy L402 API

Cryptographic random bytes from hardware RNG.

5-10 sats per call, paid over the Lightning Network. No API key and no signup: the request returns 402 Payment Required, the caller pays the invoice, and retries with the proof of payment.

l402_entropy 5-10 sats

Parameters

bytes 32-256 format hex/base64

Call it with curl

The first call answers 402 with a Lightning invoice in the WWW-Authenticate header. Pay it from any Lightning wallet, then repeat the call with the L402 token and preimage.

curl -X POST https://lightningfaucet.com/api/ \
  -H "Content-Type: application/json" \
  -H "Authorization: L402 $MACAROON:$PREIMAGE" \
  -d '{"action":"l402_entropy","bytes":32,"format":"hex"}'

Call it from an AI agent

With lightning-wallet-mcp the payment is handled for you. From the CLI:

lw pay-api "https://lightningfaucet.com/api/l402/entropy?bytes=32&format=hex"

In Claude Code, Cursor or any MCP host, ask the agent to call pay_l402_api with that URL. The fee is 1% of the price, rounded down, so calls under 100 sats carry no platform fee.

All Utility APIs endpoints · How L402 authentication works · List your own API on the gateway