Sats for BotsLearn
What is L402?
L402 revives HTTP status 402 "Payment Required". A server answers a request with a 402, a Lightning invoice and a macaroon (a scoped token). The agent pays the invoice, then retries with the macaroon plus the payment preimage as proof. No accounts or API keys. Spec: lightninglabs/L402.
What is Nostr Wallet Connect?
NWC lets an app or agent control a remote Lightning wallet over Nostr relays, with permissions and budgets the owner sets. It is a common way to give an agent a spending wallet. See nwc.dev.
What is Cashu?
Cashu is a Chaumian ecash protocol backed by Bitcoin via Lightning mints. Tokens are bearer and private, which suits tiny per-request payments. See cashu.space.
L402 vs x402 vs MPP
| L402 | x402 | MPP | |
|---|---|---|---|
| Rail | Bitcoin Lightning | Mainly stablecoins on EVM chains (e.g. Base, Polygon) and Solana; designed to extend to cards | Stripe / Tempo |
| Proof of payment | Macaroon + Lightning preimage | Signed payment payload in a PAYMENT-SIGNATURE header | Stripe-managed |
| Settlement | Lightning invoice paid between channels | Onchain transaction, usually submitted by a "facilitator" | Stripe/Tempo |
What is x402?
x402 is an open standard for payments over HTTP. Like L402 it uses the 402 "Payment Required" status: the server answers with payment requirements, the client pays and retries. Its home page calls it "a neutral standard, not tied to any specific network", with stablecoins as the primary use case (x402.org).
Who backs it: x402 was started at Coinbase, which contributed the protocol to the Linux Foundation. The x402 Foundation launched operationally on July 14, 2026, with 40 member organizations, including Coinbase, Cloudflare, Google, Stripe, Visa, Mastercard and Circle (announcement).
How it differs from L402:
- Rails: L402 is Lightning-only and priced in sats. x402 is chain-agnostic and mostly settles in stablecoins.
- Settlement: x402 payments land onchain. A facilitator service verifies the client's signed payload and submits the transaction, or the server does it itself (x402 docs). L402 payments clear as a Lightning invoice, and the preimage is the receipt (L402 spec).
- Custody: neither protocol needs a custodian. x402's docs say the facilitator "does not hold funds". With L402, the payer uses its own Lightning wallet or node, and Lightning Agent Tools keeps keys on a remote signer.
- Privacy: x402 settlements are ordinary transactions on public blockchains. Lightning payments happen off the base chain inside payment channels, so individual payments aren't each recorded onchain.
Why Sats for Bots lists only Lightning: we focus on one open, Bitcoin-native rail so every listing works with sats and the same agent wallet. We cover x402 and MPP here as context.
A directory of endpoints across all three: 402 Index.