KaleidoPay
Pay with what you have. Receive what you want.
One reusable BOLT12 QR says which layers the receiver accepts, in order: Bark, Arkade, Lightning, on-chain. The payer's wallet reads it and quotes every route it can pay, directly or through a swap provider found on Nostr. Any other BOLT12 wallet still sees a normal offer.
Built at bitcoin++ Berlin, 1–3 October 2026, by Walter and Mo.
Site, videos and slides: https://kaleidoswap.github.io/kaleido-pay/
How it works
- Receiver: in Rate, connect your LDK node over Nostr Wallet Connect, pick and order the layers you accept, and your node issues one reusable BOLT12 offer carrying that order in an
ssps_rails record (SSPS §5.3, type 1000000385). Bark and Arkade entries carry your address; an on-chain address travels next to the offer in a BIP321 link.
- Payer: scan. KaleidoPay shows the receiver's order and quotes every route, fees included: Bark to their Bark address, the offer over Lightning, Bark's on-chain send, or an Electrum swap provider found on Nostr. You pick; nothing moves until you confirm.
Details: docs/ARCHITECTURE.md and docs/bolt12.md.
Beyond Bark: Nostr Lightning Swap Providers
The payer's wallet only needs to read the rails and pay Lightning; Bark is the first wallet wired in. A Nostr Lightning Swap Provider announces on Nostr which rails it delivers to, quotes a swap from Lightning, and locks the receiver's asset on the receiver's rail for the same payment hash, so both sides settle or neither does.
- Live today: Electrum's swap providers (Lightning → on-chain bitcoin), quoted on mainnet in Rate.
- Next: a receiver lists
liquid:mainnet/<USDt asset id>, the payer pays sats over Lightning, a provider (for example a KaleidoSwap maker) locks USDt on Liquid, and the claim pays the receiver. The same pattern covers L-BTC, Arkade and RGB assets on Lightning, with Arkade, Spark or any Lightning node as the payer.
This repository
| Folder | What |
|---|
packages/universal-code | The rails record codec, BIP321 + offer, network detection, route planner |
packages/swap-market | Client for Electrum's swap providers over Nostr: discover, quote, reverse swap, claim, recovery |
signet/ | Our offer nodes (LDK fork) and Electrum swap providers on signet and Mutinynet |
demo/ | Command-line demos, the offer inspector, and the demo videos |
site/ | The GitHub Pages site and slides |
The app lives in kaleidoswap/Rate (branch hack/universal-bolt12), which imports the packages from here. The LDK changes are on branch feat/offer-ssps-rails of our forks of rust-lightning, ldk-node and ldk-server. The spec is kaleidoswap/ssps.
Quick start
npm install
npm test # offline checks
npm run offers -w @universal-bolt12/swap-market mainnet # live swap providers on Nostr
npm run offer -- --decode lno1... # read an offer's rails
Status
Proven:
- Scan → receiver's order → live quotes for every route, on mainnet in Rate (quotes only).
- The LDK fork issues offers with the receiver's rails over encrypted NWC (regtest, and signet with a real node); a wallet that doesn't know the record still pays the offer.
- Electrum swaps over Nostr fully paid and claimed on Mutinynet (24 s and 19 s) with our own provider.
- Bark pays Lightning and Arkade receives Lightning on mainnet (small amounts).
Not yet:
- A complete payment from Bark through an enriched QR end to end.
- Arkade paying an Arkade address directly (needs a fee estimate from the wallet library).
- A per-payment lock (
ssps_lock) from the receiver instead of a static address.
Built at the hackathon
Everything in this repository was written during the event, as were the LDK fork branches, Bark support in wallet-engine and Rate, and KaleidoPay in Rate. Rate, wallet-engine and the SSPS drafts existed before.
License
MIT
