Contract Event Monitor

Watch for specific smart contract events in real-time. Filter by event signature, parameters, and transaction details. Perfect for NFT mints, token transfers, and protocol events.

What is a Contract Event Monitor?

A Contract Event Monitor listens for events emitted by smart contracts. When a matching event is detected, you receive an alert with full event details.

Use Cases

NFT Minting: Alert when new tokens are minted
Large Transfers: Detect token transfers above threshold
Governance: Track proposal creation and voting
Protocol Upgrades: Monitor upgrade events
DeFi Activity: Watch swap, borrow, liquidation events

Configuration

Field	Description	Example
Contract Address	Smart contract to monitor	0x1234...5678
Chain	Blockchain	Ethereum, Polygon, etc.
Event Signature	Event to watch	Transfer(address,address,uint256)
ABI	Contract ABI (optional)	JSON ABI
Filters	Event parameter filters	amount > 1000000
Interval	Check frequency	1m, 5m

Configuration Examples

NFT Mint Detection

{
  "type": "contract_event",
  "name": "NFT Mint Monitor",
  "chain": "ethereum",
  "contractAddress": "0xBC4CA0EdA7647A8aB7C2061c2E118A18a936f13D",
  "eventSignature": "Transfer(address,address,uint256)",
  "filters": {
    "from": "0x0000000000000000000000000000000000000000"
  },
  "interval": 60000
}

Large Token Transfer

{
  "type": "contract_event",
  "name": "USDC Large Transfer",
  "chain": "ethereum",
  "contractAddress": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
  "eventSignature": "Transfer(address,address,uint256)",
  "filters": {
    "value": { "gte": "1000000000000" }
  },
  "interval": 60000
}

Governance Proposal

{
  "type": "contract_event",
  "name": "New Proposal Created",
  "chain": "ethereum",
  "contractAddress": "0x...",
  "eventSignature": "ProposalCreated(uint256,address,string)",
  "interval": 300000
}

Event Filters

Filter by Indexed Parameters

// Transfer event: Transfer(address indexed from, address indexed to, uint256 value)

// Filter: Only transfers FROM specific address
"filters": {
  "from": "0x1234...5678"
}

// Filter: Only transfers TO specific address
"filters": {
  "to": "0xabcd...ef01"
}

// Filter: Transfers between two addresses
"filters": {
  "from": "0x1234...5678",
  "to": "0xabcd...ef01"
}

Filter by Value

// Greater than
"filters": {
  "value": { "gte": "1000000000000" }
}

// Less than
"filters": {
  "value": { "lte": "100000000" }
}

// Range
"filters": {
  "value": { 
    "gte": "1000000",
    "lte": "10000000"
  }
}

Alert Example

🔔 Contract Event Detected

Contract: BAYC NFT (0xBC4C...f13D)
Event: Transfer
Chain: Ethereum

Details:
- From: 0x0000...0000 (Mint)
- To: 0x1234...5678
- Token ID: #9547
- Transaction: 0xabcd...ef01
- Block: 18,234,567

[View on Etherscan]

Common Event Signatures

ERC-20 Token Events

Transfer(address indexed from, address indexed to, uint256 value)
Approval(address indexed owner, address indexed spender, uint256 value)

ERC-721 NFT Events

Transfer(address indexed from, address indexed to, uint256 indexed tokenId)
Approval(address indexed owner, address indexed approved, uint256 indexed tokenId)
ApprovalForAll(address indexed owner, address indexed operator, bool approved)

Uniswap V2 Events

Swap(address indexed sender, uint amount0In, uint amount1In, uint amount0Out, uint amount1Out, address indexed to)
Mint(address indexed sender, uint amount0, uint amount1)
Burn(address indexed sender, uint amount0, uint amount1, address indexed to)

Best Practices

1. Use Specific Filters

Avoid monitoring ALL Transfer events. Filter by address or value:

✅ Good: Transfer events where value > 1M USDC
❌ Bad: All Transfer events (too noisy)

2. Set Appropriate Check Intervals

High-frequency events: 1-2 minutes
Low-frequency events: 5-15 minutes
Governance events: 15-30 minutes

3. Include Contract ABI

Providing the ABI enables automatic event parsing:

Human-readable event names
Decoded parameter values
Type-safe filtering

4. Monitor Multiple Contracts

For protocols with multiple contracts:

Create separate monitor for each contract
Tag monitors for organization
Use same alert channels

Troubleshooting

No Events Detected

Possible Causes:

Event signature incorrect
Contract address wrong
Filters too restrictive
Event not emitted yet

Solution:

Verify event signature matches contract ABI
Test with broader filters first
Check contract on block explorer

Too Many Alerts