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WalletX

WalletX

A full-stack ERC-4337 Account Abstraction smart wallet with gasless transactions, session keys, and real-time transaction lifecycle visualization.

Source Code
github.com/niladri-gudu/walletx

Overview

WalletX is a production-grade ERC-4337 smart wallet implementation that demonstrates the full Account Abstraction stack — from UserOperation construction to on-chain execution. Instead of regular Ethereum transactions, users sign UserOperations that flow through a bundler, get validated by a custom VerifyingPaymaster, and execute via a programmable smart wallet contract. The project showcases gasless UX, delegated session key access, and a real-time transaction lifecycle visualizer.

What Users Can Do

  • Connect their EOA wallet via RainbowKit and interact with a deployed smart wallet.
  • Send gasless transactions where the VerifyingPaymaster covers all gas fees.
  • Create session keys with fine-grained permissions — restricted target address, ETH cap, and expiry time.
  • Execute transactions using session keys without owner signature involvement.
  • Track the full UserOperation lifecycle in real-time — from signing to bundler submission to on-chain confirmation.
  • Revoke session keys instantly to remove delegated access.
  • View confirmed transactions with direct Etherscan links.

Why I built this

  • To deeply understand ERC-4337 Account Abstraction — the most important UX primitive in Web3.
  • To implement a custom VerifyingPaymaster from scratch and understand the signature verification flow.
  • To master the UserOperation lifecycle — how bundlers, EntryPoints, and smart wallets interact.
  • To build session keys as a senior-level feature that demonstrates programmable wallet logic.
  • To complete Phase 6 of the '6 Projects in 60 Days' challenge with the most infrastructure-heavy project yet.

Tech Stack

Solidity
Next.js
Nest.js
TypeScript
Viem
Wagmi
Turborepo

After launch & Impact

  • Successfully implemented a custom VerifyingPaymaster that reconstructs userOpHash internally to match EntryPoint's computation — solving a non-trivial signature verification challenge.
  • Built a complete two-hash signing flow where the paymaster signs with empty paymasterData and the wallet signs after paymasterData is finalized.
  • Implemented session key enforcement at the contract level using assembly-based calldata decoding to validate target address and ETH amount per transaction.
  • Integrated Pimlico bundler with sponsorship policy management to ensure the custom paymaster is respected.
  • Delivered a real-time transaction lifecycle UI that animates through each stage of the UserOperation flow.

Future Plans

  • Add multi-owner support and on-chain multisig validation.
  • Implement ERC-20 token gas payments via a token paymaster.
  • Add social recovery — allow trusted guardians to restore wallet access.
  • Build a session key marketplace where dApps can request scoped access from users.
  • Integrate The Graph to index UserOperation history for a full transaction dashboard.