SaucerSwap V3

SaucerSwap V3 is a central limit order book (CLOB) for spot trading on Hedera. You buy or sell tokens against orders at specific prices, instead of depositing liquidity into an automated market maker (AMM) pool. Tokens remain in your wallet until a trade settles on-chain.

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How an order book works

A market pairs a base token with a quote token. In SAUCE/USDC, for example, you buy or sell SAUCE at a price expressed in USDC per SAUCE. A buy order spends the quote token to receive the base token; a sell order does the reverse. A large trade may fill against several orders at different prices. A displayed price does not mean your entire trade can execute at that price; available depth and your order’s price limits determine what can fill. See Slippage for the difference between a quote and the execution you accept.

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Makers and takers

A maker adds an order that can be filled by another trader. A taker removes available liquidity by trading against it. The distinction depends on how an order fills, not simply whether you selected a limit or market order. A limit order priced to cross the opposite side of the book can take liquidity immediately. Its unfilled remainder may rest on the book, where later fills act as maker fills. Maker rebates, where configured, are funded by taker fees rather than SAUCE emissions; see Fees and rebates.

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Order types

The trading tutorial covers the web app. Maker-only and OCO parameters are documented in the Orderbook API; do not assume every API option is exposed in the interface. OCO links are managed off-chain, so they do not provide an atomic on-chain guarantee that only one order can fill.

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Off-chain matching, on-chain settlement

V3 separates order entry from settlement:

1. You approve the required token allowance and sign an order message containing its trade parameters.
2. The off-chain matching engine maintains the book and finds fills.
3. The settlement contract, called the reactor, verifies signatures and executes the matched trades atomically on Hedera.

Signing an order does not deposit tokens into the book. Your wallet must retain the required balance and allowance for settlement; spending those tokens elsewhere can prevent an open order from filling. Token approvals are separate standing permissions, potentially for a maximum amount until revoked, rather than a limit that applies only to your next signed order. Submitting orders and requesting cancellation through the off-chain service do not require a network transaction for each request. The protocol pays the network settlement fee on V3 fills, while traders pay their applicable trading fee. Wallet setup transactions and direct on-chain cancellation can still incur network fees.

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Order book and AMM liquidity

V3 operates alongside V1 and V2. Where enabled, an order can opt into AMM-backed settlement within its signed parameters. This backstop lets V3 orders use pool liquidity without turning the order book into an AMM pool. The swap page compares an eligible V3 quote with the best V1/V2 AMM quote and selects one venue for the trade. This quote comparison is separate from AMM-backed settlement within V3. See Swap routing for the selection rules.

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Cancellation and settlement risks

An order can be partially filled before you cancel it; cancellation affects only what remains unfilled. An accepted cancellation request is not confirmation that matching or settlement has stopped. Check the final order and fill status before placing a replacement that could duplicate your trade. SaucerSwap Labs operates the off-chain order entry, matching, and market-data services. Availability depends on that infrastructure even though your tokens remain in your wallet until settlement. Audit coverage is specific to the reviewed contracts and versions; see Audits.

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Next steps