Glossary

Hedera and project terms used across this template.

HederaCopy Anchor Link

• HTS — Hedera Token Service. Hedera's native token service, reachable from Solidity at the system contract 0x167. Here it mints the order NFTs, moves USDC/DAI/WHBAR, and wipes an NFT at settlement. HTS tokens are also exposed as ERC-20/ERC-721, so ordinary transfer/approve/ownerOf work.
• HSS — Hedera Schedule Service. The scheduling service, at system contract 0x16b (HIP-1215). A contract calls scheduleCall to have the network run a future call, and hasScheduleCapacity to check a second has room. This template uses it to run each market's sweeps with no bot.
• HCS — Hedera Consensus Service. Hedera's ordered-message log. Not used by this template — there is no messaging or audit-log need here; the on-chain events plus the mirror node cover the order trail.
• Exchange-rate system contract (0x168). Converts a USD-cent amount to tinybar at the live HBAR rate, so the vault can price gas budgets in cents and charge them in HBAR.
• Mirror node. Hedera's read API for history and state (transactions, logs, token balances, associations). The frontend reads order history and the trail from it; there is no indexer to run.
• tinybar / weibar. HBAR has 8 decimals on Hedera (a tinybar is 1e-8 HBAR). The EVM expresses value with 18 decimals (a weibar), so 1 HBAR = 1e8 tinybar = 1e18 weibar and 1 tinybar = 1e10 weibar. Contracts see msg.value in tinybar; wallets and the JSON-RPC relay use weibar. utils/orders/units.ts is the only place amounts cross that boundary.
• Association. On Hedera an account must be associated with a token before it can hold it. The UI associates the order NFT collection and the output token for you (HIP-719 associate()), or the account needs free auto-association slots.
• ECDSA vs ED25519 keys. Hedera accounts can use either; the EVM tooling here (relay, wallet, deploy) needs an ECDSA (secp256k1) key, which has a matching 0x EVM address.
• Account id vs EVM address. The same account has a Hedera id (0.0.x) and a 20-byte EVM address (0x…); the mirror node maps between them.
• HashScan. Hedera's block explorer. Every proof link in the README opens there.

SaucerSwap and oraclesCopy Anchor Link

• SaucerSwap V2. The Uniswap-V3-style concentrated-liquidity DEX on Hedera. Fills route through its exactInputSingle, and the guard reads a pool's own TWAP via observe.
• TWAP — time-weighted average price. The pool's average price over a window (twapWindow), harder to manipulate than the spot price. The guard compares it to Chainlink.
• Chainlink feed. A price oracle (e.g. HBAR/USD, USDC/USD). The order's trigger and the swap's minimum-out are priced from Chainlink; the guard blocks a fill unless the pool TWAP is within maxDeviationBps of it.

This templateCopy Anchor Link

• OrderVault. The contract that escrows orders, mints the NFTs, schedules the sweeps, and fills.
• Order NFT. Each order is an HTS NFT whose serial number is the order id. Whoever holds it can cancel it and receives the fill; transferring the NFT transfers the order.
• The guard. The check before every fill: fresh Chainlink feeds and a pool TWAP within a bounded deviation. It can be Open, or closed for OracleStale, DeviationTooHigh, etc.
• Sweep. One scheduled pass over a market's open orders: it fills the ones whose trigger is met and the guard allows, charges each checked order, and schedules the next sweep.
• Budget. The HBAR a maker prepays with an order to cover its scheduled checks. When it runs out the order is parked until topped up.
• Distance-aware scheduling. The next sweep waits roughly as long as the price would need to move to reach the nearest trigger (wait = distanceBps × 3600 / maxMoveBpsPerHour, clamped), so far-off orders are checked rarely and near ones often.
• Escrow. The input token the vault holds for an open order; refunded on cancel, swapped on fill.
• Slippage. The most the swap may give up versus the Chainlink price (slippageBps); the minimum-out is Chainlink's price less this.
• restartSweep. A permissionless call that reschedules a market whose sweep stopped (see the residual-stall note in the architecture doc).