Ethereum Validator Performance Dashboard

A full-stack dashboard for monitoring Ethereum validator attestation performance, computing missed rewards using the Altair consensus specification, and reconciling results against beaconcha.in.

Quick Start

Prerequisites

• Node.js 18+
• An Ethereum Beacon Chain RPC endpoint (e.g., Alchemy, Infura, or Quicknode)

Setup

# Clone and install backend
cd backend
npm install

# Configure .env (BEACON_RPC is required)
# Example: BEACON_RPC=https://eth-mainnetbeacon.g.alchemy.com/v2/YOUR_KEY
cp .env.example .env  # Edit with your API key

# Start backend (port 3000)
npm run dev

# In a separate terminal, start frontend (port 8000)
cd frontend
npx http-server . -p 8000 --cors -c-1

Open http://localhost:8000 in your browser.

---

Architecture

├── backend/                  # Express.js REST API
│   ├── src/
│   │   ├── api/              # Route definitions
│   │   ├── controllers/      # Request handling
│   │   ├── services/         # Core business logic
│   │   │   ├── beaconService.js        # Beacon chain RPC client
│   │   │   ├── attestationService.js   # Attestation analysis via beaconcha.in
│   │   │   ├── rewardEngine.js         # Altair reward formula (BigInt)
│   │   │   ├── validatorService.js     # Main orchestrator
│   │   │   ├── reconciliationService.js # Cross-check with beaconcha.in
│   │   │   └── validatorLookupService.js # Pubkey → index resolution
│   │   ├── cache/            # File-based epoch caching
│   │   ├── config/           # Constants (Altair spec values)
│   │   └── utils/            # Logger, retry, epoch math
│   └── package.json
│
└── frontend/                 # Static HTML/CSS/JS dashboard
    ├── index.html
    ├── css/styles.css
    └── js/
        ├── config.js         # Validator pubkeys & app settings
        ├── api.js            # Backend API client with chunking
        ├── app.js            # Main application logic
        ├── renderer.js       # DOM rendering
        ├── chart.js          # Chart.js trend visualization
        └── utils.js          # Formatting, validation, helpers

---

API Contract

GET /api/validators/performance

Query Parameters:

Parameter	Type	Description
validators	string	Comma-separated validator public keys
startEpoch	number	Start epoch (inclusive)
endEpoch	number	End epoch (inclusive), max range: 3000

Response:

{
  "validators": [
    {
      "index": 123456,
      "effectiveness": 99.5,
      "totalMissedEth": 0.000012,
      "missedSource": 0.000003,
      "missedTarget": 0.000006,
      "missedHead": 0.000003,
      "missedAttestations": 1,
      "totalAttestations": 225,
      "wrongSourceCount": 0,
      "wrongTargetCount": 0,
      "wrongHeadCount": 1,
      "correctCount": 224
    }
  ],
  "epochs": [...],
  "reconciliation": [...],
  "missingEpochs": [],
  "pubkeyMap": { "123456": "0x89ca..." },
  "meta": { "startEpoch": 100, "endEpoch": 200, "computeTimeSeconds": 12.5 }
}

---

Altair Reward Formula

Implemented directly from the Altair consensus specification:

base_reward = effective_balance × BASE_REWARD_FACTOR / isqrt(total_active_balance)
missed_reward = base_reward × flag_weight / WEIGHT_DENOMINATOR

Flag	Weight	Timeliness Requirement
TIMELY_SOURCE	14	Included within 5 slots
TIMELY_TARGET	26	Included within 32 slots
TIMELY_HEAD	14	Included in the next slot

Constants: BASE_REWARD_FACTOR = 64, WEIGHT_DENOMINATOR = 64

The implementation uses BigInt for integer square root (isqrt) to match the spec's integer arithmetic.

---

Participation Flag Strategy

The full beacon state (~hundreds of MB) is impractical to fetch per epoch. Instead, we use beaconcha.in's attestation API as a proxy:

• Fetch attestation records per validator from GET /api/v1/validator/{index}/attestations
• Derive flags from inclusionslot - attesterslot (inclusion delay):
  • Source: delay ≤ 5 slots
  • Target: delay ≤ 32 slots
  • Head: delay = 1 slot
  • Missed: no attestation record or status = 0

Accuracy trade-off: This approach accurately captures missed attestations and late inclusions. However, it cannot detect incorrect source/target/head votes — only late or missing ones. In practice, incorrect votes are rare for well-configured validators, so the impact is minimal.

If beaconcha.in goes down: The dashboard will show zero attestation data (not cached data). The total active balance is cached for 1 hour from the beacon RPC. A future improvement would cache attestation data locally.

---

Caching Strategy

• Total active balance: In-memory cache, 1-hour TTL. Fetched from beacon RPC GET /eth/v1/beacon/states/head/validators?status=active_ongoing.
• Epoch data: File-based cache in backend/cache/. Each epoch stored as epoch_{N}.json. Recent epochs (<1 hour old) are not served from cache to allow finalization.
• Validator effective balances: Fetched live per request (small/fast call).
• Beaconcha.in requests: Rate-limited to ~10 req/min (free tier).

---

Tracked Validators

#	Public Key (truncated)
1	0x89ca02...a580fa
2	0xaf6609...d7bfdb
3	0x8d357d...2aee76
4	0xb936fc...d41891
5	0xa72e6d...ce74db

---

Development

# Backend with auto-reload
cd backend && npm run dev

# Frontend with live server
cd frontend && npx http-server . -p 8000 --cors -c-1

Backend runs on port 3000, frontend on port 8000.