⇆ rails · any asset, any rail_◻×
Settlement surface

Any asset.
Any border.

The settlement engine is asset-agnostic: every rail below plugs into the same HTLC atomic-swap path. The table tracks which rails the runtime knows about today, and exactly what needs to happen for each to start moving real value.

Live on mainnet
Scaffolded — activation requires community infra
Future — needs runtime upgrade
◉ crypto rails_◻×
T

Twill Native · TWL

rail: TwillInternal · domain: Crypto
Direct on-chain transfer. 0.10% fee of debit volume (fee-free during the first 10M mined). Atomic. Final. Every cross-asset swap routes through TWL as the common ledger.
● Live
B

Bitcoin · BTC

rail: Bitcoin · domain: Crypto
HTLC address derived from the settlement hashlock on the Bitcoin side. Runtime type defined. Activation requires a confirmation oracle set and a custody arrangement (qualified custodian or FROST/MPC threshold bridge) — both decisions are governance proposals.
Scaffolded
Ξ

Ethereum · ETH

rail: Ethereum · domain: Crypto
HTLC contract pattern. Runtime type defined. Activation requires a deployed ERC-20 HTLC contract and oracles confirming finality at a configurable block-confirmation depth.
Scaffolded
◎

Solana · SOL

rail: Solana · domain: Crypto
Program-derived HTLC escrow for SPL-token settlement. Runtime type defined. Activation requires the on-Solana program deployment and oracle set.
Scaffolded
$

USD Coin · USDC

rail: Usdc · domain: Crypto
Stablecoin rail riding the same ETH HTLC infrastructure. Runtime type defined. Activates once the ETH rail is live.
Scaffolded
…

Other crypto assets

rail: Other · domain: Crypto
Catch-all bucket for assets wrapped through the Assets pallet without a dedicated rail. Promoting one to first-class is a runtime upgrade — governance proposal only.
Future
✦ carbon rails_◻×
✦

Verra VCU · tCO₂e

rail: Verra · domain: Carbon
The carbon pallet already enforces a 100 TWL issuance bond and a 7-day public dispute window. Minting a Verra credit on-chain requires a registry-confirmation oracle — activation depends on Verra API access.
Scaffolded
✧

Gold Standard · tCO₂e

rail: GoldStandard · domain: Carbon
Same pallet-carbon machinery as Verra, different registry. Runtime type defined. Activation depends on the registry API + an oracle-confirmed retirement loop.
Scaffolded
💱 fiat rails · community completion_◻×

Fiat rails exist in the runtime as explicit scaffolding. They activate only when community organisations or payment partners step up to run off-chain confirmation oracles. No timeline is promised. These are explicitly future — community completion.

€ SEPA
EUR

SEPA confirmation oracles required. Runtime upgrade + vote.

Future
$ ACH
USD

ACH confirmation oracles required. Runtime upgrade + vote.

Future
W SWIFT
WIRE

International correspondent-banking confirmation relayed on-chain.

Future
₹ UPI
INR

UPI confirmation relayed by community operators.

Future
◐ how activations happen_◻×
Path from scaffolded to live

Oracle set · deployment · vote

  1. An oracle operator set stakes TWL and starts posting signed price and/or confirmation feeds for the rail in question.
  2. Bridge or registry contracts are deployed on the counterparty chain or coordinated with the registry API.
  3. A community proposal registers the activated rail: oracle set, staleness bounds, fee-share parameters.
  4. If the proposal passes, the rail starts routing settlements in the next block.
# Every rail plugs into the same primitive.
settlement.create({
  leg_a: { asset: TWL,  amount, from },
  leg_b: { asset: BTC,  amount, to   },
  hashlock,
  timelock,
})

# Atomic: both legs clear, or neither does.