# EVM Transaction Explainer

> EVM Transaction Explainer is a paid API for AI agents from x402.ottoai.services, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-11).

Decodes any EVM blockchain transaction hash into a human-readable summary across 11 supported chains

## Facts

- Endpoint: GET https://x402.ottoai.services/tx-explainer?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-ottoai-services-8b5c1e0e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_wG45zNhlQQjVJ-3WMTxFh

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 x402-ottoai-services-8b5c1e0e
```

Example prompt: Can you explain what happened in this Ethereum transaction — 0x4a3b2c1d9e8f7a6b5c4d3e2f1a0b9c8d7e6f5a4b3c2d1e0f9a8b7c6d5e4f3a2b — give me a detailed breakdown?

## When to prefer this

Use this endpoint when you need to decode an opaque EVM transaction hash into human-readable information — especially for DeFi interactions like swaps, liquidity additions, approvals, and token transfers. Supports 11 chains including Base, Ethereum, Arbitrum, Optimism, Avalanche, Polygon, Mantle, Monad, Plasma, BSC, and Hyperliquid. Ideal for wallets, portfolio tools, or any agent that needs to explain blockchain activity to a non-technical user.

## Known failure modes

- Invalid or malformed transaction hash returns an error field in the response
- Transaction hash not found on the specified chain returns a failed status
- Unsupported chain name returns a validation error
- Network timeouts when fetching on-chain data
- Transaction pending or very recent may not yet be indexed

## How this service works

Decode and explain any EVM blockchain transaction across 11 chains (Base, Ethereum, Arbitrum, Optimism, Avalanche, Polygon, Mantle, Monad, Plasma, BSC, Hyperliquid). Get a human-readable summary of swaps, transfers, approvals, DeFi interactions, and more.

## Output

Returns a human-readable summary of the transaction (e.g. 'User swapped 1 ETH for 3,200 USDC on Uniswap'), the chain name, a link to the block explorer, transaction status (success/failed), and optionally a detailed breakdown of all events, token flows, and contract interactions involved.

## Example request

```json
{
 "input": {
  "type": "http",
  "method": "GET",
  "queryParams": {
   "chain": "ethereum",
   "txHash": "0x5c504ed432cb51138bcf09aa5e8a410dd4a1e204ef84bfed1be16dfba1b22060",
   "outputLevel": "summary"
  }
 }
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "txHash"
     ],
     "properties": {
      "chain": {
       "enum": [
        "base",
        "ethereum",
        "arbitrum",
        "optimism",
        "avalanche",
        "polygon",
        "mantle",
        "monad",
        "plasma",
        "bsc",
        "hyperliquid"
       ],
       "type": "string",
       "description": "Blockchain network (default: base). 11 EVM chains supported."
      },
      "txHash": {
       "type": "string",
       "pattern": "^0x[a-fA-F0-9]{64}$",
       "description": "Transaction hash (0x-prefixed, 64 hex characters)"
      },
      "outputLevel": {
       "enum": [
        "summary",
        "detailed"
       ],
       "type": "string",
       "description": "'summary' = one-liner, 'detailed' = full breakdown"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "status"
     ],
     "properties": {
      "chain": {
       "type": "string",
       "description": "Blockchain name"
      },
      "error": {
       "type": "string",
       "description": "Error message if failed"
      },
      "status": {
       "enum": [
        "success",
        "failed"
       ],
       "type": "string"
      },
      "txHash": {
       "type": "string",
       "description": "Transaction hash"
      },
      "details": {
       "type": "object",
       "description": "Structured decode — from, to, value (in the chain's gas token: ETH, AVAX, BNB, POL…), gasUsed, gasCostNative (execution gas paid, in the chain's gas token; excludes a separate L1 data fee), gasCostUsd (always null: no live gas-token price), method, selector, signature, pattern, events (always included; interpretation prose only when outputLevel=detailed)"
      },
      "summary": {
       "type": "string",
       "description": "Human-readable transaction summary"
      },
      "explorerUrl": {
       "type": "string",
      
… (truncated)
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "chain": "Base",
  "status": "success",
  "txHash": "0x...",
  "summary": "Swapped 0.5 ETH for 1,247.83 USDC via Uniswap V3",
  "explorerUrl": "https://basescan.org/tx/0x..."
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-ottoai-services-8b5c1e0e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.ottoai.services](https://www.zero.xyz/host/x402.ottoai.services/llms.txt)