Thread by @mcutler

1/14 A new mental model to help wrap your mind around #ERC4337: 4337 adds a new “user intent layer” upstream/on top of the existing transaction flow.

The big unlock (for me at least): working backwards from the current Ethereum EOA model. 🧵

2/14 Let’s start with the current EOA tx flow. A user accesses their EOA via a non-custodial wallet – such as Metamask or Ledger – to compose, sign, and submit a TX to the public mempool. The ‘sign & submit’ step is critical because 4337 does not require a hard fork. How?

3/14 Under ERC-4337, users access their on-chain Smart Contract Wallet via a 4337-compliant wallet. But in order to make changes to their Smart Contract Wallet, users still need to compose/sign/submit a valid transaction to the network… which still requires an EOA of course.

4/14 Enter the Bundler! A critical actor in the 4337 transaction flow, Bundlers act as a ‘proxy EOA’ on behalf of end-users and their 4337 wallets. Bundlers compose/sign/submit ‘bundled’ transactions that specify Smart Contract Wallet actions via the EntryPoint Contract.

5/14 Bundlers receive candidate instructions via the ‘Alt-Mempool’ – a new, programmable transaction layer that operates independently of the current Public Mempool. Alt-Mempools introduce all sorts of interesting new possibilities (and complexity) to the network.

6/14 Finally, via their 4337-wallet, users specify their TX intent via pseudo-transaction objects known as userOps. For example, a TX intent userOp might specify “transfer this NFT from my Smart Contract Wallet to Cold Storage” and be transmitted to an Alt-Mempool.

7/14 To summarize: ERC-4337 introduces a new User Intent Layer upstream of the existing EOA transaction flow. Users of 4337-wallets will transmit their Intents via Alt-Mempools. Bundlers then transform those Intents into signed transactions that the network can act on.

8/14 ERC-4337 changes everything & nothing. Everything: 4337 redefines what Ethereum TX can be – making them more programmable & expressive. Nothing: from the POV of the chain, we had signed EOA TX before 4337 & now we have signed EOA TX after 4337.

9/14 Thank you to @ChrisMeisl @drakefjustin @thegostep @yuan_han_li @bertcmiller @_danielmarzec @MuratLite @blairlmarshall @ThisIsJoules @zachkrasner and many others for their feedback here. Are you 4337-curious? Our team @blocknative gotchu:

10/14 On Thursday, March 23, we’ll be hosting 4337-focused Community Call via Twitter Spaces to dive deeper into all things Account Abstraction – with special guest @johnrising_ from @stackup_fi. Join us!

https://twitter.com/blocknative/status/1638233037006856193

11/14 ERC-4337 has implications for the MEV supply chain. Researcher @_danielmarzec on our team recently published his perspectives – very much worth a read.
hackmd.io/@dmarz/4337-me…

12/x Take a spin through our new 4337 UserOps Explorer. 4337.blocknative.com

13/14 Use our Mempool Explorer to monitor pending 4337 EntryPoint Contract transactions: tinyurl.com/2f5ej8kh. Open this link in a new browser tab and let it sit for a while… it will pick up 4337-relevant transactions like this one.

14/14 Review the @blocknative end-to-end overview of ERC-43376 (authored by @ThisIsJoules), which goes deeper into many of the topics covered in this thread, including:
✅UserOperations
✅alt-mempools
✅Bundlers
✅EntryPoint contract
✅Much more

blocknative.com/blog/account-a…