Pair Addresses

getPair
The most obvious way to get the address for a pair is to call getPair on the factory. If the pair exists, this function will return its address, else address(0) (0x0000000000000000000000000000000000000000).
The “canonical” way to determine whether or not a pair exists.
Requires an on-chain lookup.
CREATE2
Thanks to some fancy footwork in the factory, we can also compute pair addresses without any on-chain lookups because of CREATE2. The following values are required for this technique:
​
​
address
The factory address​
salt
keccak256(abi.encodePacked(token0, token1))
keccak256(init_code)
0x96e8ac4277198ff8b6f785478aa9a39f403cb768dd02cbee326c3e7da348845f
token0 must be strictly less than token1 by sort order.
Can be computed offline.
Requires the ability to perform keccak256.
Examples
Solidity
address factory = 0x5C69bEe701ef814a2B6a3EDD4B1652CB9cc5aA6f;
address token0 = 0xCAFE000000000000000000000000000000000000; // change me!
address token1 = 0xF00D000000000000000000000000000000000000; // change me!
​
address pair = address(uint(keccak256(abi.encodePacked(
  hex'ff',
  factory,
  keccak256(abi.encodePacked(token0, token1)),
  hex'96e8ac4277198ff8b6f785478aa9a39f403cb768dd02cbee326c3e7da348845f'
))));

Flash Swaps

Supporting meta transactions

Last modified 2yr ago


`address`	The factory address
`salt`	`keccak256(abi.encodePacked(token0, token1))`
`keccak256(init_code)`	`0x96e8ac4277198ff8b6f785478aa9a39f403cb768dd02cbee326c3e7da348845f`