A decentralized order book called Granola just got its first public demo, and it’s doing something genuinely novel: enabling atomic swaps between different types of ecash tokens, all without a central server, custodian, or intermediary touching the funds.
The project, built on top of the Cashu ecash protocol and coordinated through Nostr, was showcased by Cashu contributor callebtc. In its current form, Granola lets users trade between BTC-backed and USD-backed ecash in a testnet environment, with the entire system designed so that clients never relinquish custody of their tokens.
How Granola actually works
At its core, Granola is a trading layer that uses two existing Bitcoin-adjacent protocols as building blocks. Cashu provides the ecash tokens themselves, which are privacy-preserving digital bearer instruments based on Chaumian blind signatures. Nostr, the decentralized social protocol, handles both the public broadcasting of orders and private coordination between trading parties.
The settlement process follows a structured three-message protocol. A trader proposes a reserve, the counterparty accepts it, and then a quote gets locked in. The technical terms for these steps are reserve_propose, reserve_accept, and quote_lock. Each trading session generates ephemeral Nostr public keys, meaning that individual trades aren’t easily linkable to a user’s persistent identity.
