Granola is a Cashu-based exchange concept built for SatsHack by Vinteum in October 2024, with the final pitch presented at Satsconf 2024.

The public SatsHack submission lists Breno Brito and Luis Schwab as the team behind the project, and states that the entire project was built during the hacking period.

SatsHack pitch

SatsHack / Satsconf 2024

Granola was part of the second SatsHack by Vinteum, a hackathon tied to Satsconf 2024. The public event timeline scheduled the final pitches for November 8, 2024 at Satsconf, with winners announced on November 9, 2024.

Public coverage after the event recorded Granola as one of the highlighted winners:

• No Bullshit Bitcoin listed Granola as 3rd place overall and Best Nostr.
• Livecoins also highlighted Granola among the winning Satsconf / SatsHack projects.
• Portal do Bitcoin had covered the hackathon beforehand, noting that SatsHack would culminate with finalists pitching at Satsconf.

What the project proposed

The original SatsHack submission framed the main problem as privacy on Bitcoin on- and off-ramps. The proposed solution was to combine Cashu with Nostr so peers could publish and coordinate atomic, cross-mint ecash swaps without relying on a centralized exchange.

In practice, the idea was to treat different Cashu mints as currency-specific issuers and use the same hash/preimage across both sides of the trade. That turns the exchange into a peer-to-peer, privacy-first settlement flow rather than a custodial venue.

Protocol diagram

sequenceDiagram

actor Alice
participant Nostr
actor Carol
participant Mint

Alice-->>Nostr: Generate new \n ephemeral PubKey
Alice->>Nostr: Publish Order

Nostr->>Carol: Fetches 8338 events \n Sees order
Carol-->>Nostr: Generate new \n ephemeral PubKey
Carol->>Alice: Sends DM \n with pay request \n via Nostr

Alice->>Carol: Generates H\n sends HTLC_c to PubKey
Carol-->>Mint: Verify HTLC_c
Carol->>Alice: Sends HTLC_a with the same H
Carol-->>Mint: Subscribe \n to HTLC_a
Alice->>Mint: Swaps HTLC_a token revealing preimage
Mint-->>Carol: State change with preimage
Carol->>Mint: Swaps HTLC_c token

Proposed flow

1. Alice generates a fresh ephemeral pubkey and publishes an order on Nostr.
2. Carol sees the order, creates her own ephemeral pubkey, and sends a DM with a pay request.
3. Alice generates a secret and sends HTLC_c, locked to the corresponding hash.
4. Carol verifies HTLC_c, creates HTLC_a with the same hash, and subscribes to its state change.
5. Alice swaps HTLC_a, revealing the preimage in the process.
6. Carol learns the preimage from that state transition and uses it to swap HTLC_c.

Why it is interesting

• Nostr can work as a lightweight order-discovery and messaging layer.
• The exchange flow is peer-to-peer rather than custodial.
• The original hackathon framing pushed the idea beyond BTC-only settlement and toward cross-mint, multi-currency ecash swaps.
• The same direction can evolve into broader work on atomic swaps between Cashu mints.
• Granola starts as a protocol sketch first, not as a polished product.

Status

Granola is currently an early design note rather than a production system. The interesting part is the mechanism: combining Nostr coordination with hash-locked exchange flows for Cashu-style e-cash.

Links

Official SatsHack Submission GitHub Repo Pitch Video No Bullshit Bitcoin Coverage Livecoins Coverage Portal do Bitcoin on SatsHack