80trust / 100

Top Crypto

by SYNTHORA in Onchain & crypto

x402 APIPassing, checked 2 h ago

SYNTHORA top-crypto: Top N cryptocurrencies by market cap (default 10, max 50): rank, price, 24h change, volume and market cap in USD. Source: CoinGecko free API, keyless, timestamped.

POST
https://api.hergertsynthora.com/v1/top-crypto
Price
$0.01
per call in USDC
Uptime
100%
last 30 days
Response time
245 ms
340 ms slowest 5%
Last check
Passed
2 h ago, next any minute now

Run a free test callHow to call it

Reliability

All checks passedSome failedAll failedNot checked

Status and outage history · Atom feed

How to call it

POST https://api.hergertsynthora.com/v1/top-crypto

Each call costs $0.01 in USDC on Base, paid with the request over x402.

Run a free test callOne unpaid request, the way an agent sends it. You see the payment challenge it gets back. Nothing is charged.

Example request

From the listing.

POST https://api.hergertsynthora.com/v1/top-crypto
content-type: application/json

{
  "limit": 10
}

Parameters

ParameterTypeRequiredDescription
limitintegerNotop N, default 10, max 50

Example response

The provider's example. We can't check it without paying.

{
  "niche": "top_crypto",
  "ok": true,
  "receipt": {
    "alg": "ed25519"
  },
  "result": {}
}

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.01.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://api.hergertsynthora.com/v1/top-crypto' \
  -H 'content-type: application/json' \
  --data-raw '{"limit":10}'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - -X POST 'https://api.hergertsynthora.com/v1/top-crypto' \
  -H 'content-type: application/json' \
  --data-raw '{"limit":10}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode
JavaScript: pay and call
// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.01 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.01" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.01 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fapi.hergertsynthora.com%2Fv1%2Ftop-crypto&method=POST
const res = await pay("https://api.hergertsynthora.com/v1/top-crypto", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "limit": 10
  }),
});
console.log(res.status, await res.text());
Python: pay and call
# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.01 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.01"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://api.hergertsynthora.com/v1/top-crypto",
        json={
            "limit": 10,
        },
    )
    print(res.status_code, res.text)

Security scan

1 finding

  • Payment address changed recently in payment
    Payment address changed from 0xEf879BFD6C4AccB8F795136de90246e1EC245e06 to 0x6D9F318463168fF637b50E5b9a21392e97c7c167

Recent checks

WhenResultHTTPTimePrice
2 h agoPassed402340 ms$0.01
6 h agoPassed402246 ms$0.01
10 h agoPassed402773 ms$0.01
14 h agoPassed402245 ms$0.01
18 h agoPassed402275 ms$0.01
Show 10 older checks
22 h agoPassed402199 ms$0.01
26 h agoPassed40253 ms$0.01
30 h agoPassed402244 ms$0.01
34 h agoPassed402340 ms$0.01
38 h agoPassed402218 ms$0.01
42 h agoPassed402210 ms$0.01
45 h agoPassed402286 ms$0.01
2 days agoPassed402209 ms$0.01
2 days agoPassed402281 ms$0.01
2 days agoPassed402217 ms$0.01

History

12 Oct 2026Payment address changed from 0xEf879BFD6C4AccB8F795136de90246e1EC245e06 to 0x6D9F318463168fF637b50E5b9a21392e97c7c167