Partner hubs and in-flight FX

In the bank network, the Lightning layer is run by the institutions themselves. Partner hubs hold multi-asset channels, and AMM contracts convert currency inside a payment, so a cross-currency transfer settles atomically or not at all.

Updated 08 Nov 20261 min read

#Partner hubs

Partner banks and curated fintechs run hub nodes: well-capitalised, always-online Lightning nodes holding channels with their own clients, with other hubs, and with the network's AMM operators.

#Multi-asset channels

A single channel's allocation records balances in several SQRL instruments at once, for example a bank-issued local-currency stablecoin alongside a USD stablecoin. Each balance is tracked and co-signed under the same sequence-numbered allocation.

#In-flight FX

An AMM is an SCL contract holding two-sided inventory in a currency pair, operated by an admitted market maker and quoting a deterministic curve. When a payment crosses a currency boundary, the route passes through a hub hosting the relevant AMM:

  1. The inbound HTLC delivers the source-currency asset.
  2. The AMM contract prices the conversion.
  3. The outbound HTLC carries the destination-currency asset.

All three are keyed to the same payment hash, so the conversion settles atomically with the payment or not at all. The sender knows the delivered amount before committing, and there is no settlement-risk window between legs.

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Example

A client of Bank A holds NGNx in a channel with Hub A and pays a client of Bank B. The payment routes through the hub hosting the NGNx/USDx AMM, converts at the contract's quote, and arrives as USDx in the recipient's channel with Hub B, under one payment hash end to end. Bitcoin is touched only at channel opens, closes and batch settlement.

#Corridors

A corridor is assembled from parts the network already defines: an issuer on each side, a hub on each side, an AMM on the pair, and ordinary Lightning routing between them. Adding a corridor is a liquidity and licensing exercise, not an engineering one. SQRL Markets is the desk banks run corridors from.

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