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EVM Event Log Decoder
x402
EVM Event Log Decoder is a paid API for AI agents from defi-shield-hazel.vercel.app, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-15).
Decodes raw EVM event log data (topics and data fields) into human-readable event names and typed parameters
Price / call$0.1
Success—
StatusUnknown
How this service works
Decodes on-chain event data into structured fields. Submit raw event logs to receive human-readable decoded output.
Output
Returns the event name (e.g. 'Transfer'), the full event signature (e.g. 'Transfer(address,address,uint256)'), the event signature hash, decoded argument key-value pairs (e.g. from/to/value), raw topics, topic count, match source (e.g. 'known_events'), raw data, and response time in milliseconds.
Example use cases
Monitor DeFi token transfers in real-time
“I'm watching a blockchain for token movements. I just got a raw event log with data 0x0000000000000000000000000000000000000000000000000000000000000064 and topics [0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef, 0x000000000000000000000000aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa, 0x000000000000000000000000bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb]. Can you decode this and tell me what event it is, who sent tokens to whom, and how many?”
Analyze Uniswap swap events from transaction logs
“I'm tracking Uniswap trades on Base chain. I have a raw log from a swap transaction with data 0x00000000000000000000000000000000000000000000000000000000000003e8 and topics [0xc42079f94a6350d7e6235f29174924f928cc2ac818eb64fed8004e115fbcca67, 0x0000000000000000000000003333333333333333333333333333333333333333, 0x0000000000000000000000004444444444444444444444444444444444444444]. Decode this for me so I can understand which tokens were swapped and the amounts involved.”
Parse unknown smart contract event emissions
“I just intercepted a transaction log from a smart contract I'm not familiar with. The raw data is 0x0000000000000000000000000000000000000000000000008ac7230489e80000 and the topics are [0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925, 0x0000000000000000000000005555555555555555555555555555555555555555, 0x0000000000000000000000006666666666666666666666666666666666666666]. What event was emitted here and what are the parameter values?”
Technical details
Endpoint
POSThttps://defi-shield-hazel.vercel.app/api/data/event-decodeWhen to prefer
Use this endpoint when you have raw EVM transaction receipt log data (hex-encoded data and topics arrays) and need to convert them into human-readable event names and typed parameter values. Ideal for DeFi analytics pipelines, transaction monitoring agents, or any workflow that processes on-chain events from Ethereum, Base, or other EVM-compatible chains and needs structured, interpretable output without running a full node or maintaining a local ABI registry.
Side effects
- Unknown event signature hash — returns no match if the topic0 hash is not in the known events registry
- Malformed hex data — invalid or truncated log_data or log_topics cause parsing errors
- Missing required fields — omitting log_topics or log_data results in a 400-style error
- Ambiguous ABI — logs from unverified contracts with non-standard events may not decode correctly
- Payment failure — x402 payment of 0.1 USDC not provided or rejected
Input
{
"log_data": "0x0000000000000000000000000000000000000000000000000000000000001000",
"log_topics": [
"0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef",
"0x0000000000000000000000001111111111111111111111111111111111111111",
"0x0000000000000000000000002222222222222222222222222222222222222222"
]
}Output
{
"success": true,
"raw_data": "0x0000000000000000000000000000000000000000000000000000000000001000",
"event_name": "Transfer",
"raw_topics": [
"0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef",
"0x0000000000000000000000001111111111111111111111111111111111111111",
"0x0000000000000000000000002222222222222222222222222222222222222222"
],
"topic_count": 3,
"decoded_args": {
"to": "0x2222222222222222222222222222222222222222",
"from": "0x1111111111111111111111111111111111111111",
"value": "4096"
},
"match_source": "known_events",
"event_signature": "Transfer(address,address,uint256)",
"response_time_ms": 1,
"event_signature_hash": "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"
}Tags
x402
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