Cafe-Chi is a fully operational arbitrage bot for the CHI-ETH pair on Uniswap. Most arbitrage relies on complex routing algorithms to find the most profitable path through a series of exchanges. In contrast, Cafe-Chi takes advantage of the fact that ETH can be used to mint CHI -- the two assets are uniquely coupled.
The price of CHI on Uniswap can be used to compute a sort of market-rate gas price
for transactions. Cafe-Chi sends transactions with gas prices slightly lower than
that market rate. If they get confirmed, CHI can be minted for less ETH than it
would take to buy it. The difference is taken as profit. Since profits are always
in ETH and always get send back to tx.origin, Cafe-Chi is self-sustaining.
All Solidity code is under the contracts directory. In theory one could mint CHI,
then trade it on Uniswap, but here we use a flash swap for fun. Before going through
with the mint, the code checks that the transaction will be profitable according
to tx.gasprice (technically some gas is spent before this check, but it's
negligble compared to what would get spent during minting). If you're confused
about the math here, check out the excellent graphic at the top of this page.
Solidity code has already been deployed. Addresses can be found in the corresponding Javascript wrapper. I haven't verified the code on Etherscan, but feel free to check it yourself or deploy your own contracts.
Javascript source code and tests are located in the src and tests directories
respectively.
Install dependencies:
yarn install
After installation, you'll probably want to run some tests just to make sure your
environment is set up correctly. Make sure your .env contains a PROVIDER_INFURA_ID
and a PROVIDER_ALCHEMY_KEY. If you'd rather use your local node via IPC or some other
combination of providers, just multiple the array that's used to instantiate
MultiSendProvider in tests/setup.js. Then run:
yarn test
To actually run Cafe-Chi, you'll want to customize config.json. Each
entry in the txManagers object should have its own envKeyAddress and envKeySecret.
These should reference the name of the .env variable that contains your address and
secret. For example, if your address is stored in the MY_ADDRESS variable, you should
set envKeyAddress: "MY_ADDRESS". Note that the "secret" is your private key without
the '0x' at the beginning, while your address should include the '0x'.
Other parameters:
interval: How often (in seconds) to check market conditions and send new transactionsnumPending: How many transactions to keep pending at any given time. Don't set this too high, as you will eventually exhaust the arbitrage opportunity and all remaining transactions will fail.ratio: The percent of market-rate gas price that your transactions will be sent at. For example, if the CHI-ETH pair thinks its CHI was minted at 30 gwei, and you set this to .99, your transactions will be sent at 29.7 gwei. Higher ratios are more likely to get confirmed, but lower ones result in more profit.providers: Specifies what services will be used to send transactions. Infura will work just fine. See tests/setup.js for how to specify an Infura or Alchemy provider.
Also note that each txManager will run in its own Node.js process.
Finally, it can be useful to get notifications when transactions are sent. If you want Slack messages, add a SLACK_WEBHOOK environment variable. Otherwise you can remove Slack from the winston transports array in src/setup.js.
Ready to start? Run:
yarn cafe-chi
I recommend running this inside of a tmux session (tmux new -s cafechi) so that it
will run even if your SSH connection / terminal window gets closed.
Experiment with the various parameters to see how consistently you can get transactions to go through, or modify the Solidity code to mint different amounts of CHI at once (I have one that mints 140 and another that mints only 10). As long as your account starts out with ~0.2 ETH, you should be able to sit back and watch your balance grow (albeit rather slowly). Good luck!
P.S. If you're a developer, feel free to write some tests for CafeChi.sol and/or submit a PR to use truffle rather than OpenZeppelin CLI.
USE THIS CODE AT YOUR OWN RISK! There's no warranty of any kind, and I can't promise that you'll make money. Do your own research.