# Base Transaction Lookup by Hash

> Base Transaction Lookup by Hash is a paid API for AI agents from 402.com.tr, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-14).

Fetches detailed on-chain data for a Base network transaction by its hash, including value, gas, fees, method selector, and explicit flags for contract creation and pending status.

## Facts

- Endpoint: GET https://402.com.tr/api/x402/base-tx
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/base-transaction-lookup-by-hash-cdb284ac
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Jpf850dI8W91mrPDnsjIx

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 base-transaction-lookup-by-hash-cdb284ac
```

Example prompt: Can you pull up the details for this Base transaction — 0x4a3b...f2e1 — and tell me the sender, receiver, ETH value, what method was called, and whether it's still pending?

## When to prefer this

Use this endpoint when you need structured, machine-readable Base transaction data including explicit semantic flags (contract creation, pending status) rather than inferring them from null fields yourself. Prefer this over generic blockchain explorers when you need a clean JSON response with both wei and ETH values, the 4-byte selector, and calldata size in a single pay-per-call call. Especially useful for agents that need to route logic based on whether a tx is a deployment, a call, or a plain transfer, without parsing raw RPC responses.

## Known failure modes

- Unknown or invalid transaction hash returns {found: false} rather than an error — agent must check this flag
- Missing hash query parameter causes a validation error
- Transactions on networks other than Base are not found
- Very recent transactions may show as pending (null block) before confirmation
- Malformed hash strings may return found: false or a 400-level error

## How this service works

🆕 A Base transaction by hash, unedited: from, to, value in wei and ETH, nonce, gas, fee caps, type, and the 4-byte method selector with the calldata size. Flags a contract creation (null to) and a still-pending transaction (null block) rather than leaving you to infer either. Unknown hashes answer found:false, not an error.

## Output

Returns a JSON object containing: found (boolean), and if found: from, to (null for contract creation), value in wei and ETH, nonce, gas limit, maxFeePerGas, maxPriorityFeePerGas, transaction type, 4-byte method selector, calldata size in bytes, a contractCreation boolean flag, and a pending boolean flag (true if block is null). Unknown hashes return {found: false} rather than an error.

## 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"
    },
    "pathParams": {
     "type": "object"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "hash"
     ],
     "properties": {
      "hash": {
       "type": "string",
       "description": "Transaction hash"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/base-transaction-lookup-by-hash-cdb284ac/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from 402.com.tr](https://www.zero.xyz/host/402.com.tr/llms.txt)