B402 Preflight

Last 30 days

Uptime

100%

Response time

39 ms typical, 39 ms slowest 5%

Last check

5 h ago

Next check

any minute now

How to call it

# See the payment challenge (nothing is charged)
curl -i -X POST "https://api.oblique.markets/api/v1/paid/b402-preflight" \
  -H "content-type: application/json" \
  -d '{"amount":"example","asset":"native/BNB or a BEP-20 contract address","chain":"bnb","deadline":"example","fee_cap":"Maximum network fee in BNB","intent_id":"example","payer":"example","recipient":"example"}'

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { ExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client().register(
  "eip155:8453",
  new ExactEvmScheme(privateKeyToAccount(process.env.AGENT_KEY)),
);
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? Preflight it first for $0.005:
// GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fapi.oblique.markets%2Fapi%2Fv1%2Fpaid%2Fb402-preflight
const res = await pay("https://api.oblique.markets/api/v1/paid/b402-preflight", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({"amount":"example","asset":"native/BNB or a BEP-20 contract address","chain":"bnb","deadline":"example","fee_cap":"Maximum network fee in BNB","intent_id":"example","payer":"example","recipient":"example"}),
});
console.log(await res.json());

Example input

{
  "amount": "example",
  "asset": "native/BNB or a BEP-20 contract address",
  "chain": "bnb",
  "deadline": "example",
  "fee_cap": "Maximum network fee in BNB",
  "intent_id": "example",
  "payer": "example",
  "recipient": "example"
}

Example output

{
  "amount": "0.01",
  "amount_units": "10000000000000000",
  "asset": "BNB",
  "asset_balance": "0.125",
  "chain": "eip155:56",
  "decision": "ready",
  "evidence_hash": "sha256:4e8f1a2c6d8b0f2e4a6c8e0f2a4c6e8f0a2c4e6f8a0b2c4d6e8f0a2c4e6f8a0b2",
  "evidence_source": "public_bsc_rpc",
  "fee_cap_bnb": "0.0005",
  "fee_cap_sufficient": true,
  "fee_headroom_bnb": "0.1245",
  "intent_hash": "sha256:9c2d7b3f6e1a4c8b0d2e5f7a9b1c3d5e7f9a1b3c5d7e9f1a3b5c7d9e1f3a5b7c9",
  "intent_id": "invoice-2026-08-21-001",
  "payer": "0x1111111111111111111111111111111111111111",
  "recent_activity": {
    "incoming_transfer_count": 5,
    "latest_block": 61500000,
    "lookback_blocks": 2000,
    "nonce": 42,
    "outgoing_transfer_count": 3
  },
  "recipient": "0x2222222222222222222222222222222222222222",
  "recipient_valid": true,
  "signature": "hmac-sha256:7a4e1c9b3d5f7a9c1e3b5d7f9a1c3e5b7d9f1a3c5e7b9d1f3a5c7e9b1d3f5a7",
  "signing_key_id": "b402-preflight-v1",
  "timestamp": "2026-08-21T20:00:00.000Z"
}

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