crypto.tx

Live EVM transaction status and receipt lookup. Give a transaction hash + chain and get back whether it mined successfully, reverted, or is still pending in the mempool, plus block number, confirmations, timestamp, sender and recipient, value transferred (native unit), gas used, effective gas price, total fee paid, any contract created, and event-log count. Chains: base, ethereum, polygon, arbitrum, optimism. Real-time post-training chain state — use it to confirm a payment settled, detect a reverted transaction, or wait for confirmations before acting. Unknown hash returns 404. Sibling of /api/crypto/gas-oracle (fees) and /api/crypto/address-validate (format).

price
$0.0010 USDC per call
method
GET/api/crypto/tx
payment
x402 v2 · USDC on Base (EIP-3009) or Solana (SPL transfer)
auth
None. Sign the payment, retry with PAYMENT-SIGNATURE.

Overview

The tx API is a pay-per-call crypto endpoint built for AI agents and autonomous software. Live EVM transaction status and receipt lookup.

There is no signup and no API key. An agent (or any HTTP client) hits the endpoint, receives an x402 "402 Payment Required" challenge, signs a sub-cent USDC payment on Base or Solana, and retries — the data comes back on the paid request. That makes it a drop-in tx data source for an agent tool-use loop, an MCP host, or a backend that needs crypto data on demand without onboarding to yet another vendor portal.

Use cases

Parameters

NameTypeDescription
chainrequiredstringEVM chain to query: base | ethereum | polygon | arbitrum | optimism.
one of: base | ethereum | polygon | arbitrum | optimism
hashrequiredstringTransaction hash: 0x followed by 64 hex characters.
match ^0x[0-9a-fA-F]{64}$

Code samples

cURLbash
# 1. Probe with no auth → 402 envelope with PaymentRequirements
curl -sS 'https://2s.io/api/crypto/tx?chain=base&hash=example'

# 2. Sign + retry with PAYMENT-SIGNATURE:
curl -sS 'https://2s.io/api/crypto/tx?chain=base&hash=example' \
  -H 'PAYMENT-SIGNATURE: <base64-json-payload>'

# Or use the canonical runner (handles probe → sign → retry):
#   EVM_PRIVATE_KEY=0x... node --env-file=.env.local \
#     --experimental-strip-types scripts/x402-pay.ts \
#     'https://2s.io/api/crypto/tx?chain=base&hash=example'
TypeScript / Node — @2sio/sdktypescript
import { TwoS } from '@2sio/sdk'

const client = new TwoS({
  privateKey: process.env.EVM_PRIVATE_KEY as `0x${string}`,
})

const result = await client.crypto.tx({
  "chain": "base",
  "hash": "example"
})

console.log('endpoint:', result.endpoint)
console.log('cost:', result.costUsd, 'USDC')
console.log('tx:', result.settlement?.txHash)
console.log('data:', result.data)
Python — 2siopython
import os
from twosio import TwoS

client = TwoS(private_key=os.environ["EVM_PRIVATE_KEY"])

result = client.crypto.tx(chain="base", hash="example")

print("endpoint:", result.endpoint)
print("cost:", result.cost_usd, "USDC")
print("tx:", (result.settlement or {}).get("tx_hash"))
print("data:", result.data)
MCP — Claude Desktop / AgentKit / any MCP hostjson
// 1. Add @2sio/mcp to your MCP host config (Claude Desktop example below).
//    EVM_PRIVATE_KEY funds x402 payments per call.

// claude_desktop_config.json
{
  "mcpServers": {
    "2sio": {
      "command": "npx",
      "args": ["-y", "@2sio/mcp"],
      "env": { "EVM_PRIVATE_KEY": "0x..." }
    }
  }
}

// 2. Once the server is running, agents call this tool via standard MCP:

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "crypto.tx",
    "arguments": {
      "chain": "base",
      "hash": "example"
    }
  }
}

Response

FieldTypeDescription
okboolean
one of: true
itemsarray
totalintegerTotal matching rows upstream; null when unknown.
sourceobject
Example response datajson
{
  "ok": true,
  "items": [
    {}
  ],
  "total": 1,
  "source": {
    "provider": "example",
    "url": "example",
    "license": "example"
  }
}

FAQ

Do I need an API key to use the tx API?
No. crypto.tx is x402-native — there is no signup and no API key. Your client makes the call, receives a 402 with payment requirements, signs a USDC payment, and retries. Funds come from a wallet you control.
How much does the tx API cost?
$0.0010 USDC per call, charged per request. There are no monthly fees, seats, or minimums — you pay only for the calls you make.
Can I try the tx API for free first?
Yes. Add ?trial=1 (or the header X-2s-Trial: 1) to get a free real call per endpoint per hour, so you can verify the response shape before wiring payment.
Which networks and tokens are supported?
USDC on Base (via EIP-3009 transferWithAuthorization) or Solana (SPL transfer), using the open x402 payment protocol.
How do I call crypto.tx from an AI agent or MCP host?
Use @2sio/sdk (TypeScript), 2sio (Python), or the @2sio/mcp server for any MCP host — each handles the probe → sign → retry loop for you. See the code samples on this page.

Discovery

Related: tx api · crypto tx api · tx api for ai agents · x402 crypto api · tx api no api key · pay per call tx api · crypto api