I’ve been working on uniswap front runners for around 4 months. And I’d love to share some interesting points here. First of all, shout out to Yannick(twitter:@YannickCrypto). He has been helping me with my fr and we have found some really cool stuff together.
Front runner works like this. When a uniswap swap (swap eth -> token A, the gas fee is 50 gwei) appears on network, you catch it and decode the parameters. The swap will increase the price of token A. So you buy the token A with gas fee 50 + 1/10^9 gwei and sell it with 50 - 1/10^9 gwei. You will probably earn some money here because these 3 txs show in the blk with the order : your buy tx, target tx, your sell tx. I will mention some cases that will let you lose money.
Arbs just find the possible arb paths that will make them money. For instance, when a uniswap tx appears (swap eth -> token A, the gas fee is 50 gwei), the arb bot may find a path like eth -> B -> A -> eth, and the output eth is more than input. So he will send out a tx with gas price as 50 gwei to make the money.
These are the basic ideas. So front runners have to be the first one that buy target token A. Otherwise, they can’t get the token A with the cheapest price. Meanwhile, if other frs buy then they also buy the token, the target uniswap token will fail with insufficient output error. In this case, all frs will lose money here. So you can see all those frs bidding up the gas price to be the first one that buys token A.
So I’d love to share some key notes here.
You have to find some way to save gas. Sometimes, the profit is big for one tx, those frs will bid up the gas price to like 10k. And you will find some bots only pay like 60k gas for the first buy tx while those small bots pay like 120k gas. This is why those big frs earn more money.
When you do the first buy tx and later, the target tx (eth -> A) appears, this may create possible profitable arb paths. Like eth -> B -> A -> eth we mentioned before. This will let you lose money. Because the arb actually sells the A in eth-A pool. This decrease the price of A.
There are some evil frs that buy token A secretly. And they trigger your fr bot to buy that token. Then sell the token after your buy tx. In this case, you will lose a lot money. This fucking bot here caused me lose some money as I remember.
0xCBAeD798a675Fc24077424BbD184A8c1EaA61939
I will share some fr and arb addresses here for you. So you can study from them.
front runners
0x0000000071e801062eb0544403f66176bba42dc0
0x00000000002bde777710C370E08Fc83D61b2B8E1
0x000000000000084e91743124a982076c59f10084
0x8be4db5926232bc5b02b841dbede8161924495c4
0x42d0ba0223700dea8bca7983cc4bf0e000dee772
0x5f3e759d09e1059e4c46d6984f07cbb36a73bdf1
0xafe0e7de1ff45bc31618b39dfe42dd9439eebb32
0x7e3b29AFCAFf75fa1DBe16cF5C4C1086FE57F4e9
0xe39adcd1ce4c4370e65f8e82fe651d4091259620
arbs
0xc117CeFc617295579FfF745b59c0fE89698B0f59
0x7ee8ab2a8d890c000acc87bf6e22e2ad383e23ce
0x78a55b9b3bbeffb36a43d9905f654d2769dc55e8
0x860bd2dba9cd475a61e6d1b45e16c365f6d78f66
0x68A3f74c58FcCE5dAB312B2dfCCeafFcCA953057
0xCA004470CC29574390217Cc9dfd37919b4DC4681
0x7c651d7084b4ba899391d2d4d5d3d47fff823351
0xb8db34f834e9df42f2002ceb7b829dad89d08e14
0x860bd2dba9Cd475A61E6d1b45e16c365F6D78F66
0xFA2ea19De0c5eD9D3E1e05325A9983F8ef570459Good luck bro. These days too many bots out there and the gas fee is crazy high. So my bot won’t make money anymore. I give it up now. Maybe you can have luck. Who knows.