feat: Leverage EIP-7917 Based Preconfirmations for Sub-Second Transaction UX

[hadv]

Summary

Leverage EIP-7917 (Deterministic Proposer Lookahead) and based preconfirmations to provide sub-second transaction confirmation feedback to EthAura users.

Status Update (Dec 5, 2025):

• ✅ Fusaka upgrade live on Ethereum mainnet (Dec 3, 2025)
• ✅ EIP-7917 active - proposer lookahead now available
• ✅ Research complete - mev-commit FAST RPC identified as recommended integration path

Current UX Pain Points

1. Gas estimation: 2-5 seconds
2. Bundler submission: Variable wait
3. Block inclusion: 12+ seconds (best case)
4. Finality: 12.8 minutes for full economic finality

Users see a spinning "Pending" state for 12+ seconds minimum.

Proposed Solution

With EIP-7917 + based preconfirmations:

1. Preconfirmation: 100-500ms (proposer commitment)
2. Block inclusion: 12 seconds (guaranteed by commitment)
3. Finality: 12.8 minutes (unchanged)

Key insight: Users get instant feedback that their transaction WILL be included, backed by economic guarantees (slashing via Symbiotic).

Preconf Ecosystem Status (Dec 2025)

Protocol	Status	Integration Path
mev-commit (Primev)	✅ Live on Mainnet	FAST RPC for wallets ⭐
Commit-Boost	✅ Production Ready	Validator sidecar
Bolt (Chainbound)	🔄 Development	Permissionless preconfs
Pimlico/Alchemy	❓ Unknown	No public preconf API

Recommended Path: Integrate with Primev FAST RPC - production-ready RPC endpoint designed for wallets/dApps.

Transaction Flow with Preconfirmations

sequenceDiagram
    participant User
    participant EthAura
    participant FAST_RPC as Primev FAST RPC
    participant Proposer
    participant Blockchain
    
    User->>EthAura: Submit Transaction
    EthAura->>FAST_RPC: Send UserOp
    FAST_RPC->>Proposer: Request Preconf
    Proposer-->>FAST_RPC: Signed Commitment
    FAST_RPC-->>EthAura: Preconf Receipt (100-500ms)
    EthAura-->>User: "Preconfirmed ✓"
    Note over User: Instant feedback!
    Proposer->>Blockchain: Include in Block
    Blockchain-->>EthAura: Block Confirmation
    EthAura-->>User: "Included ✓"

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Implementation Phases

Phase 1: UI Preparation ✅ Can Start Now

Issue: #165

• Build tiered confirmation state UI components
• Add preconfirmation status indicators
• Prepare toast notifications for each state

Phase 2: Bundler Abstraction ✅ Can Start Now

Issue: #166

• Abstract bundler client for preconf support
• Add preconf-aware method signatures
• Implement fallback to standard flow

Phase 3: Preconfirmation Protocol Integration ✅ Ready (Fusaka Live!)

Issue: #167 - Updated with research findings

• Integrate with Primev FAST RPC (recommended)
• Alternative: Direct mev-commit integration
• Beacon chain proposer lookahead queries
• Provider signature verification

Phase 4: Optimistic UI

Issue: #168

• Optimistic state updates on preconf receipt
• Rollback handling for broken preconfs (rare)
• Analytics and monitoring

Draft API Design

// Using Primev FAST RPC (simplest)
class PreconfBundlerClient extends BundlerClient {
  constructor(bundlerUrl, fastRpcUrl) {
    super(bundlerUrl)
    this.fastRpcUrl = fastRpcUrl
  }
  
  async sendUserOperationWithPreconf(userOp) {
    // Send via FAST RPC for automatic preconfirmation
    const result = await this.fastRpcProvider.sendUserOperation(userOp)
    
    return {
      preconfirmed: true,
      preconfHash: result.preconfHash,
      targetBlock: result.targetBlock,
      userOpHash: result.userOpHash
    }
  }
}

Dependencies & Timeline

Dependency	Status	Notes
EIP-7917	✅ Live on Mainnet	Fusaka deployed Dec 3, 2025
Preconf protocols	✅ Available	mev-commit FAST RPC ready
Bundler support	⏳ Via FAST RPC	Use Primev instead of waiting for Pimlico/Alchemy

Next Steps

1. ✅ Research complete (see feat: [Preconf Phase 3] Preconfirmation Protocol Integration (Post-Fusaka) #167 for details)
2. Contact Primev for FAST RPC access
3. Start Phase 1 - UI components can be built now
4. Test FAST RPC on testnet

Resources

• EIP-7917 Specification
• Primev mev-commit Docs
• Commit-Boost Docs
• Based Preconfirmations - Vitalik

Sub-Issues

• feat: [Preconf Phase 1] UI Preparation for Tiered Confirmation States #165 - Phase 1: UI Preparation
• feat: [Preconf Phase 2] Bundler Abstraction for Preconfirmation Support #166 - Phase 2: Bundler Abstraction
• feat: [Preconf Phase 3] Preconfirmation Protocol Integration (Post-Fusaka) #167 - Phase 3: Protocol Integration (includes ecosystem research)
• feat: [Preconf Phase 4] Optimistic UI with Preconfirmation Guarantees #168 - Phase 4: Optimistic UI

Labels

enhancement ux preconfirmations eip-7917