# EVM Event Logs by Contract, Topic, and Block Range

> EVM Event Logs by Contract, Topic, and Block Range is a paid API for AI agents from twin.unykorn.org, paid per call via x402, $0.006/call, status unknown (last checked 2026-10-01).

Retrieves on-chain event logs filtered by smart contract address, topic hash, and block range across 10 EVM-compatible chains.

## Facts

- Endpoint: POST https://twin.unykorn.org/evm-logs?utm_source=zero.xyz
- Price: $0.006/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/evm-event-logs-by-contract-topic-and-block-range-d483d21c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_9HEUlS1njZomy-6JQ6WE_

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability evm-event-logs-by-contract-topic-and-block-range-d483d21c -d '<json body>'
```

Example prompt: Pull all Transfer event logs (topic0 0xddf252ad1be2c89b69c2b068fc378daa952ba7f204e10000000000000000003e) for the USDC contract at 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 on Ethereum from block 19000000 to 19001000.

## When to prefer this

Choose this endpoint when you need on-chain EVM event logs filtered precisely by contract address, topic hash, and block range across any of 10 supported chains without running your own node. It is ideal for agents doing DeFi analytics, token transfer audits, DAO governance monitoring, or any task requiring historical smart contract events. Prefer it over general-purpose RPC providers when you want a pay-per-call model without API key management.

## Known failure modes

- Invalid contract address format (must be 0x + 40 hex chars) returns validation error
- Invalid topic0 hash format (must be 0x + 64 hex chars) returns validation error
- Unsupported chain name returns enum validation error
- Block range too large may time out or return partial results
- No matching logs in the specified range returns empty log array
- Payment failure (insufficient USDC balance) blocks request execution

## How this service works

Event logs filtered by contract, topic and block range — Genesis402 / UnyKorn Operator Network

## Output

Returns a JSON object with ok status, event log data for the matched logs, a payment receipt containing transaction hash, USD amount charged, and a receipt ID, plus a generated_at ISO8601 timestamp.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "params": {
   "type": "object",
   "properties": {
    "chain": {
     "enum": [
      "ethereum",
      "base",
      "polygon",
      "arbitrum",
      "optimism",
      "bsc",
      "avalanche",
      "gnosis",
      "linea",
      "scroll"
     ],
     "type": "string"
    },
    "topic0": {
     "type": "string",
     "pattern": "^0x[0-9a-fA-F]{64}$"
    },
    "address": {
     "type": "string",
     "pattern": "^0x[0-9a-fA-F]{40}$"
    },
    "toBlock": {
     "type": "string"
    },
    "fromBlock": {
     "type": "string"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "type": "evm-logs",
  "receipt": {
   "tx_hash": "0x<64hex>",
   "amount_usd": 0.25,
   "receipt_id": "g402-<16hex>"
  },
  "generated_at": "<iso8601>"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/evm-event-logs-by-contract-topic-and-block-range-d483d21c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from twin.unykorn.org](https://www.zero.xyz/host/twin.unykorn.org/llms.txt)