lisk-dex

Decentralized exchange module for the Lisk network. Note that lisk-dex is a community project and is not affiliated with Lightcurve or Lisk Foundation.

DEX protocol

Actions

To send an order to the DEX, a user needs to send a regular transfer transaction to the DEX's multisignature wallet address with one of the following commands in the transaction's data field.

• Limit order: ${targetChain},limit,${bidOrAskPrice},${targetWalletAddress}
• Market order: ${targetChain},market,${targetWalletAddress}
• Close order: ${targetChain},close,${orderId}
• Credit: credit

Parameters

• targetChain is the name of trading pair for a given market (e.g. LSH)
• bidOrAskPrice is a limit order price.
• targetWalletAddress is the wallet address on the opposite blockchain where tokens should be sent to.
• orderId is the order ID (which matches the blockchain transaction ID).

When making a limit or a market order, the DEX will use the amount of the underlying transaction to calculate the quantity of counterparty tokens to acquire. When performing a close order, the amount is not relevant; in this case, any amount can be specified as part of the close transaction (less is better); in any case, whatever amount is specified (minus blockchain transaction fees) will be refunded to the user's wallet via an r3 refund transaction. The credit action allows users to send tokens to the DEX wallet without triggering any operation.

Responses

These status codes and messages appear in transactions created by the DEX (as part of the transaction data field):

Refunds

• r1,${orderId}: Invalid order
• r2,${orderId}: Expired order
• r3,${orderId},${closeOrderId}: Closed order
• r4,${orderId}: Unmatched market order part
• r5,${orderId},${newWalletAddress}: DEX has moved
• r6,${orderId}: DEX has been disabled

Trades

• t1,${takerChain},${takerOrderId},${makerOrderCount}: Orders taken

• t2,${makerChain},${makerOrderId},${takerOrderId}: Order made

• Taker is the account/wallet which takes the trade from someone else (from the maker).

• Maker provides tokens for someone else to take (to the taker).

• All market orders are takers.

• Pending limit orders in the order book will be makers.

• Limit orders can be makers or takers or both.

  1. If a limit order is filled immediately as soon as placed, it is a taker.
  2. If a limit order goes into pending state after placed, it will be a maker.
  3. If a limit order is partially filled after it is placed, it is a taker; then the unfilled portion will be added to the order book and will be a maker.

• Takers are always matched against pending limit orders in the order book.

• t1 transaction represents money going into taker's wallet.

• t2 transaction represents money going into maker's wallet.

• t1 has makerOrderCount denoting number of makers it matched against from a single taker order.

• t2 is an individual maker transaction matched against a single taker order takerOrderId.

• For both market and limit orders there is always 1 t1 and 1-N t2 transactions.

Dividends

• d1,${fromHeight},${toHeight}: Member dividend

Behaviors

• If the DEX does not recognize a command/order from a user (or it is invalid for whatever reason), it will send an r1 refund transaction back to the user's wallet address which will return the full amount of the original transaction minus any blockchain transaction fees incurred by the DEX.
• A DEX adheres to a fixed order expiry. If an order expires before being filled or closed, the DEX will send an r2 refund transaction back to the user's wallet address which will return the unfilled portion of the original transaction minus any blockchain transaction fees incurred by the DEX.
• If a pending limit order is closed by a user using a close action, the unfilled portion of the original order transaction amount (minus blockchain transaction fees) will be refunded back to the user's wallet address using an r3 refund transaction. A user may only close their own orders.
• If a market order is made which cannot be completely filled by counterparty limit orders, then any unmatched part of the market order (minus blockchain transaction fees) will be refunded back to the user's wallet address as an r4 refund transaction.
• If the majority of DEX operators have agreed to move the DEX to a new multisig wallet address, the DEX will issue a full refund (minus blockchain transaction fees) for every pending order and also every new order which is sent to the DEX wallet address thereafter via r5 transactions. The DEX should keep refunding all transactions that are sent to the old address for at least 6 months in order to give clients enough time to update their caches to point to the new address.
• If the majority of DEX operators have agreed to shut down the DEX, the DEX will issue a full refund (minus blockchain transaction fees) for every pending order and also every new order which is sent to the DEX wallet address thereafter via r6 transactions. The DEX should keep refunding transactions sent to the last active address for at least 6 months to give clients enough time to update their caches to point to a different DEX. In practice, a DEX should not shut down because it does not align with financial incentives and it requires a high degree of coordination between members but this refund type exists anyway to account for unusual scenarios and use cases.
• In addition to basic blockchain fees, a DEX can charge an exchange fee as a percentage of the order value. All DEX members/nodes need to agree on the same percentage fee.

Short protocol

• For trades and refunds, only the first part of message is mandatory, the part which begins with the column character is optional depending on the market implementation.
• If one of the blockchains involved in a market does not provide sufficient space in a transaction to store a full protocol message, order IDs and wallet addresses may be trimmed down to fit within the available space.

Sponsors

Special thanks to carolina delegate for being an early sponsor of this project.