Escrowswap V1 ⬛️🐦

A secure escrow contract for an OTC trade desk.

OTC trade - OTC stands for "Over-the-Counter." In the context of financial markets, an OTC trade refers to a transaction that takes place directly between two parties without going through an exchange.

www.escrowswap.xyz - web3 platform, which allows users to create and adjust otc trades. All open trades are listed on the website for the users to navigate easily.

Why is escrowswap useful?

On-chain mechanism escrowswap offers secure experience by managing the transactions on-chain. Trust the code.
Zero slippage OTC deals are particularly useful for large volume transactions, as they provide higher liquidity. In decentralized exchanges, slippage (the price difference between the expected price and the executed price) may occur, especially for large orders or illiquid tokens.
Price stability Escrowswap offers fixed pricing for large orders, which helps maintain price stability during the transaction. On decentralized exchanges, placing a large order could result in significant price movement.
Wide Asset Selection Escrowswap allows creating trades for almost any pair of ERC20 tokens.
Privacy direct on-chain interaction with other users doesn't require verification.

FAQ

Super High-level architecture


   ,-.                                                          ,-. 
   `-'                                                          `-'
   /|\                                                          /|\
    |                                                            |
   / \                       +-------------+                    / \
  maker                      | escrowswap  |                   taker 
+-------+                    +-------------+                 +-------+
    |                               |                            |
    | createTradeOffer(id1)         |                            |
    |------------------------------>|                            |
    |                               |                            |
    | adjustTradeOffer(id1)         |                            |
    |------------------------------>|                            |
    |                               |                            |
    | cancelTradeOffer(id1)         |                            |
    |------------------------------>|                            |
    |                               |                            |
    | createTradeOffer(id20)        |                            |
    |------------------------------>|                            |
    |                               |                            |
    |                               |     acceptTradeOffer(id20) |
    |                               |<---------------------------|
    |                               |                            |

For everyone

if ETH transfer fails, we try wrapping it and sending as WETH.
if EMERGENCY WITHDRAWAL is active, only calls to cancelTradeOffer() are allowed.

For trade makers

send the whole offered amount to the contract's vault when creating a trade.
do not pay any fees
can adjust the trade
can cancel the trade and refund

For trade takers

accept the trade, receive the funds from the vault, send funds to the maker
pay the calculated fee

For the fee payment

default fee is initially set to 2% of the _tokenAmount in _tokenRequested
default fee can be adjusted to provide the best rates to stay competitive
default fee is expected to be always < 5% to avoid overflow error during execution.
unique _traidingPairFee can be set for a specific _tokenRequested -> _tokenOffered pair by escrowswap.
unique _traidingPairFee can be set to either > _baseFee or < _baseFee to provide unique rates for extreme high or low liquidity pairs.
if the _tokenRequested is low-decimal, escrowswap takes 1 unit of the mentioned token instead of the _baseFee.

Limitations

_requestedAmount is capped to TOKEN_AMOUNT_LIMIT = 23158*10^69; to avoid overflow when calculating fees.
Tokens with missing return statements are not supported.
Tokens that do not allow to send the full requested amount and require transfer fee are not supported.
Tokens that do not allow to send the amount > allowed amount mentioned in their contract might revert.

Maker (seller) functions

createTradeOffer
(_tokenOffered, _amountOffered, _tokenRequested, _amountRequested)

saves tradeOffer in the contract
creates an on-chain event
sends the full _amountOffered of _tokenOffered that user is willing to sell.

adjustTradeOffer
(_id, _tokenRequestedUpdated, _amountRequestedUpdated)

finds the trade by id and checks if the user is authorized to adjust the offer.
user is allowed to change the requested ERC20 token or/and the requested amount.

cancelTradeOffer
(_id)

finds the trade by id and checks if the user is authorized to cancel the offer.
cancels the offer, deletes it from the storage and refunds the tokens.

Taker (buyer) functions

acceptTradeOffer
(_id, _tokenRequested, _amountRequested)

checks if _tokenRequested and _amountRequested accepted by the taker actually align with the current state of the trade.
sends the _amountRequested of _tokenRequested from taker address to maker address.
sends calculated FEE in _tokenRequested to the escrowswap's payout address.
sends the trade's _amountOffered in _tokenOffered to the taker.
deletes the trade from the storage.

Escrowswap's owner functions

swithcEmergencyWithdrawal
(switch)

enables or disables the EMERGENCY WITHDRAWAL

setTraidingPairFee
(_traidingPairhash, _fee)

sets a unique fee rate for a certain _tokenRequested -> _tokenOffered pair.

deleteTraidingPairFee
(_traidingPairhash)

deletes a unique fee rate for a certain _tokenRequested -> _tokenOffered pair.

setBaseFee
(_fee)

sets a base fee rate for a all the token pairs which don't have unique fee rates.

setFeePayoutAddress
(_addr)

sets an _addr which will receive the fees on behalf of escrowswap

escrowswap / smartcontract.escrowswap