Transactions without gas?

Can someone explain to me how these transactions do not paying for gas? (0 gwei)

https://etherscan.io/tx/0xea7c2955c2f4757fcb8f82f0f4118059d5c37c1a22d48fb93d8e492160023d8e

https://etherscan.io/tx/0x8100381c8b1914694b4e8be29bf7a20cc65f1647d48200459bb97d85c35902cd

In fact, every transaction from this address:

https://etherscan.io/address/0x66f1c77db874d72e6645f1dced8eea05819b4388

has paid 0 in gas but collected $140k in GasTokens …

I would appreciate to find out how this works!

They pay the miner directly off-chain (or on-chain in another token than ETH) and the miner includes the transaction at a 0 gwei price. See MEV and Me | Paradigm Research or GitHub - flashbots/pm: Everything there is to know about Flashbots.

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Thanks Tim!

(Btw, this makes no sense for the miner, as the user prints ~1 Eth worth of GasToken each time, and the miner loses ~2-4 Eth in fees)

The miner doesn’t lose 2-4 ETH in fees: those fees are for the entire block, which contains 100-200 txns. Also, those transactions do get paid for, but just not via the transaction fee. It could be done off-chain, via a one-time payment to the miner on chain, etc.

I haven’t looked into it too deeply, though, so may be missing some details.

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I’ve also seen many 0 gas transactions exploiting the swapping on Uniswap (frontrunning, arbitraging, see Exploiting miners or security concern? 0-Fee Frontrunners).

Seems the miners are cashing in by including 0-gas tx and manipulating transaction-ordering.