Monitor USDC Transfer events on Ethereum mainnet to build a token tracker or analyze transfer patterns.
Use Case
Event logs are emitted by smart contracts when specific actions occur. This example tracks all USDC Transfer events, which you can use to:
- Build token transfer trackers
- Analyze trading patterns
- Monitor wallet activity
- Track liquidity flows
Code Example
curl --compressed -X POST 'https://portal.sqd.dev/datasets/ethereum-mainnet/stream' \
-H 'Content-Type: application/json' \
-d '{
"type": "evm",
"fromBlock": 18000000,
"toBlock": 18100000,
"fields": {
"block": {
"number": true,
"timestamp": true
},
"log": {
"address": true,
"topics": true,
"data": true,
"transactionHash": true,
"logIndex": true
}
},
"logs": [{
"address": ["0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48"],
"topic0": ["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"]
}]
}'
Try it yourself with the interactive query interface below:
Key Parameters
| Parameter | Description |
|---|
address | Contract address to filter logs. Array supports multiple addresses (OR logic) |
topic0 | Event signature (keccak256 hash of event definition). For Transfer: Transfer(address,address,uint256) |
topic1 | First indexed parameter (from address in Transfer events) |
topic2 | Second indexed parameter (to address in Transfer events) |
topics | Array containing all event topics. topic[0] is signature, topic[1-3] are indexed params |
data | Non-indexed event parameters (amount in Transfer events) |
To get the event signature, compute
keccak256("Transfer(address,address,uint256)"). The result is
0xddf252ad....
Expected Output
Each line in the response represents one block containing matching logs:
{
"header": {
"number": 18000123,
"timestamp": 1697544779
},
"logs": [
{
"address": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
"topics": [
"0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef",
"0x000000000000000000000000a9d1e08c7793af67e9d92fe308d5697fb81d3e43",
"0x00000000000000000000000028c6c06298d514db089934071355e5743bf21d60"
],
"data": "0x0000000000000000000000000000000000000000000000000000000002faf080",
"transactionHash": "0x123...",
"logIndex": 45
}
]
}
Filtering Multiple Contracts
Query logs from multiple ERC-20 tokens:
curl --compressed -X POST 'https://portal.sqd.dev/datasets/ethereum-mainnet/stream' \
-H 'Content-Type: application/json' \
-d '{
"type": "evm",
"fromBlock": 18000000,
"toBlock": 18010000,
"fields": {
"log": {
"address": true,
"topics": true,
"data": true
}
},
"logs": [{
"address": [
"0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
"0xdAC17F958D2ee523a2206206994597C13D831ec7",
"0x6B175474E89094C44Da98b954EedeAC495271d0F"
],
"topic0": ["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"]
}]
}'
- Request only needed fields: Don’t request
data if you only need addresses
- Use specific filters: Filter by contract address and event signature
- Batch appropriately: Query 10k-50k blocks at a time for best performance
- Filter by indexed parameters: Use topic1, topic2, topic3 to narrow results
