MessageVault

Overview

MessageVault is an ERC-4337 smart account deployed on Sepolia that lets users send messages to a wallet. Instead of storing message content on-chain, the contract emits events (MessageStored) and increments an internal counter, while the frontend reads messages via The Graph Subgraph for pagination and ordering.

What it demonstrates

• Account Abstraction with EntryPoint v0.7 (ERC-4337) on Sepolia
• Dual interaction model:
  • Owner (EOA) direct calls
  • AA flow via UserOperation (bundler + optional paymaster)
• Event-driven design: no message storage, just indexed events
• Subgraph “Studio-first” operations: deploy and manage in The Graph Studio
• Practical production patterns: validation surface control, deposit checks, and clear env-driven config

Key features

• sendMessageToWallet(string content) emits MessageStored(...) and advances nextMessageId
• Owner-only wiring: setEntryPoint(address) to the canonical EntryPoint
• Deposit management: addDeposit() / withdrawDepositTo(...) for AA prefund when needed
• The Graph indexing for:
  • pagination (limit, pageToken)
  • ordering by id / block metadata
• Frontend polling strategy with backoff + jitter for resilient reads

Live demo

• Open MessageVault

Screenshot

Architecture notes

• Contract

  • Smart account implements ERC-4337 validation (validateUserOp) for AA execution paths.
  • Messages are events, not storage, to keep gas low and index-friendly.

• Indexing

  • MessageStored, OwnerChanged, and EntryPointSet are indexed.
  • Subgraph is created and deployed in The Graph Studio (no local subgraph folder in repo).

• Frontend

  • Vite/React UI with WalletConnect/RainbowKit.
  • Reads events from VITE_SUBGRAPH_URL (with polling + backoff).
  • AA transactions can be sponsored (paymaster) or funded via EntryPoint deposit.

Quickstart

git clone https://github.com/casaisdev/MessageVault.git

See the repository docs:

• Backend deploy + verification + deposit checks:
  • https://github.com/casaisdev/MessageVault/blob/main/backend/README.md
• Frontend env vars + AA configuration + Subgraph polling:
  • https://github.com/casaisdev/MessageVault/blob/main/frontend/README.md

Notes

• Events over storage: message content is not persisted on-chain; the app relies on MessageStored events and Subgraph indexing for pagination and ordering.
• AA deposit vs ETH balance: Etherscan may show 0 ETH even when the wallet is “funded” for AA, prefund lives as an EntryPoint deposit, not as native balance.
• Studio-first subgraph: configure the frontend with VITE_SUBGRAPH_URL and keep endpoints out of source control.

Next steps

If I were to evolve MessageVault further:

• Add selector-level capability policies (session-style permissions with bounded actions)
• Add richer indexing at the Subgraph layer (threads, per-sender feeds, tags)
• Add a fallback read path (RPC logs) when the Subgraph is unavailable
• Add optional “reactions” or metadata events (still event-only, indexable)