Stablecoinswap API

Contract is written in Vyper (0.1.0b9)

addLiquidity

Adding liquidity is free. However, removing liquidity bears the same fee as the swap operation. This is to prevent users from bypassing the trading fee by depositing liquidity in one token and instantly withdrawing it in another token.

Smart Contract

def addLiquidity(
    token_address: address, 
    erc20_token_amount: uint256, 
    deadline: timestamp
) -> bool

Web3

contract.methods.addLiquidity(token_address, amount, deadline).send({ from: user_address }, callback)

Parameter	Type	Description
token_address	address	Address of ERC20 token to add
erc20_token_amount	uint256	How many ERC20 tokens to add
deadline	uint256	Transaction deadline

Returns
uint256	The amount of STL tokens received by the sender.

removeLiquidity

Smart Contract

def removeLiquidity(
    token_address: address, 
    stableswap_token_amount: uint256, 
    erc20_min_output_amount: uint256, 
    deadline: timestamp
) -> bool

Web3

 contract.methods.removeLiquidity(token_address, amount, min_output_amount, deadline).send({ from: user_address }, callback)

Parameter	Type	Description
token_address	address	Address of ERC20 token to remove
stableswap_token_amount	uint256	Amount of STL tokens to redeem
erc20_min_output_amount	uint256	Minimum ERC20 tokens output amount
deadline	uint256	Transaction deadline

Returns
uint256	The amount of erc20 tokens received by the sender.

swapTokens

Smart Contract

def swapTokens(
    input_token: address,
    output_token: address, 
    erc20_input_amount: uint256, 
    erc20_min_output_amount: uint256, 
    deadline: timestamp
) -> bool

Web3

contract.methods.swapTokens(input_token_address, output_token_address, input_amount, min_output_amount, deadline).send({ from: this.currentAddress() }, callback)

Parameter	Type	Description
input_token	address	Address of input ERC20 token
output_token	address	Address of output ERC20 token
erc20_input_amount	uint256	Amount of ERC20 input tokens sold
erc20_min_output_amount	uint256	Minimum ERC20 output tokens to buy
deadline	uint256	Transaction deadline

Returns
uint256	The amount of erc20 tokens received by the sender.

tokenExchangeRateAfterFees

Smart Contract

@constant
def tokenExchangeRateAfterFees(
    input_token_address: address, 
    output_token_address: address
) -> uint256

Web3

contract.methods.tokenExchangeRateAfterFees(input_token_address, output_token_address).call()

Parameter	Type	Description
input_token_address	address	Address of ERC20 token to sell
output_token_address	address	Address of ERC20 token to buy

Returns
uint265	Exchange rate multiplied by 10^22. Note that due to rounding, the fees could be slightly higher for the tokens with smaller decimal precision and/or if the exchange amount is too low.

tokenOutputAmountAfterFees

Smart Contract

@constant
def tokenOutputAmountAfterFees(
    input_token_amount: uint256, 
    input_token_address: address, 
    output_token_address: address
) -> uint256

Web3

contract.methods.tokenOutputAmountAfterFees(amount, input_token_address, output_token_address).call()

Parameter	Type	Description
input_token_amount	uint256	Amount of ERC20 token to sell
input_token_address	address	Address of ERC20 token to sell
output_token_address	address	Address of ERC20 token to buy

Returns
uint256	How many tokens can be bought for a given amount of input tokens

poolOwnership

Smart Contract

@constant
def poolOwnership(user_address: address) -> decimal

Web3

contract.methods.poolOwnership(address).call()

Parameter	Type	Description
user_address	address	Address of a user

Returns
fixed168x10 (uint168)	Share of total liquidity belonging to the user

fees

Smart Contract

@constant
def fees(fee_name: string[32]) -> decimal

Web3

contract.methods.fees(fee_name).call()

Parameter	Type	Description
fee_name	string	'ownerFee' or 'tradeFee'

Returns
fixed168x10 (uint168)	Fee value (i.e. 0.001 means 0.1%)

inputTokens

Smart Contract

inputTokens: public(map(address, bool))

Web3

contract.methods.inputTokens(address).call()

Parameter	Type	Description
address	address	Address of ERC20 token

Returns
bool	True if an address is in the list of available input tokens

outputTokens

Smart Contract

outputTokens: public(map(address, bool))

Web3

contract.methods.outputTokens(address).call()

Parameter	Type	Description
address	address	Address of ERC20 token

Returns
bool	True if an address is in the list of available output tokens

priceOracleAddress

Smart Contract

priceOracleAddress: public(address)

Web3

contract.methods.priceOracleAddress().call()

Returns
address	Address of a priceoracle contract