Architecture

Pairband splits the lifecycle of every token into three on-chain venues: curve, AMM, and book.

create()  →  PairbandToken (minter = launchpad)
buy/sell  →  bonding curve (1.0% protocol + 0.5% creator, USDC)
             └─ at $80 real USDC → PairbandAmmFactory.createPair (LP → 0xdead)
                                   PairbandBook (on-chain CLOB)
buy/sell  →  book match, then PairbandPair.getAmountOut (0.30%)
limit     →  rest on PairbandBook; cancel returns escrow

Core contracts

Contract	Role
PairbandLaunchpad	create(), curve buy/sell, graduation trigger
PairbandToken	ERC-20; minter restricted to launchpad until graduation rules apply
PairbandAmmFactory	Deploys PairbandPair at graduation
PairbandPair	Constant-product AMM (Uniswap v2-style getAmountOut, 0.30% fee)
PairbandBook	On-chain CLOB — escrowed bids/asks, price-time linked list
PairbandSettler	CCTP inbox — receives minted Arc USDC and routes to launchpad/book

Arc Testnet (5042002) and Arc Mainnet (5042) share identical bytecode. Quote and gas are USDC.

Phase 1 — Bonding curve

While status == curve:

• Virtual reserves: 80 USDC × 1,000,000,000 tokens (x·y=k)
• Buys increase USDC reserve and decrease token reserve; sells do the reverse
• Fees skimmed in USDC: 1.0% protocol, 0.5% creator
• Graduation threshold: $80 USDC (80000000 with 6 decimals) raised on the curve

The curve is the only venue until graduation. Slippage follows the bonding curve math, not the AMM.

Phase 2 — Graduation

When cumulative USDC raised reaches the threshold, the graduating buy:

1. Moves remaining token inventory + USDC into a new pair
2. Calls PairbandAmmFactory.createPair
3. Mints LP tokens and transfers them to 0x000000000000000000000000000000000000dEaD
4. Initializes PairbandBook for that market

There is no removeLiquidity path for burned LP. Liquidity is permanently locked.

Phase 3 — Book + AMM

After graduation, one ticket handles routing:

Market orders

1. Walk PairbandBook at price-time priority (linked-list order book)
2. Any unfilled size hits PairbandPair via getAmountOut at 0.30% swap fee
3. k is conserved after the fee; no fee on failed swaps (cap 2.00% in code)

Limit orders

• Rest on-chain with escrowed USDC (bids) or tokens (asks)
• Cancel returns the remainder to the maker
• No off-chain matcher — Arc's ~0.5s finality and USDC gas make resting orders practical

Cross-chain settlement

Deposits from other chains never wrap tokens onto Arc. CCTP mints native Arc USDC into PairbandSettler, which forwards into the launchpad or book. Withdrawals burn Arc USDC and mint on the destination domain.

Details: CCTP.

Configuration source of truth

Per-chain addresses and RPC endpoints live in the monorepo at packages/config/deployments.json. The docs site references those values; when launchpad or ammFactory is null, on-chain mode is not yet wired for that chain.

See Contracts.