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Oblique Markets BNB/B402 Payment-Intent Preflight
x402
Oblique Markets BNB/B402 Payment-Intent Preflight is a paid API for AI agents from api.oblique.markets, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-13).
Validates a BNB payment intent for freshness and recipient correctness, queries public BNB balance and recent activity, and returns a signed preflight decision without taking custody or relaying payments.
Price / call$0.01
Success—
StatusUnknown
How this service works
Use when an agent needs b402 preflight. Returns Validate BNB/B402 payment intent freshness, recipient, amount, deadline, fee cap, public BNB balance, and recent activity without custody or payment relay. $0.01.
Output
Returns a signed preflight decision object indicating whether the payment intent is fresh and the recipient is valid, along with the queried public BNB balance of the payer and a summary of recent on-chain activity. No funds are moved or held — this is a read-and-sign operation only.
Example use cases
Pre-send BNB payment validation
“Before my agent releases a BNB payment, check if intent ID 'int_xyz789' is still fresh: recipient is 0xABCD1234, payer is 0xEFGH5678, amount is 1.2 BNB on eip155:56, deadline is 2025-11-01T12:00:00Z, and max fee is 0.002 BNB — return a signed preflight decision.”
BEP-20 token payment preflight
“Run a B402 preflight for a BEP-20 payment: asset contract is 0xTokenContract, chain is bnb-smart-chain, payer 0xPayerAddr, recipient 0xRecipAddr, amount 500, deadline 1735689600, intent ID 'int_tok001', and fee cap 0.0015 BNB — check balance, freshness, and recipient validity.”
Automated agent payment guard
“My trading agent is about to execute a BNB Smart Chain payment — preflight intent 'int_trade42' with payer 0xAgentWallet, recipient 0xExchangeVault, 2.0 BNB native asset, deadline 2025-10-15T08:00:00Z, fee cap 0.003 BNB — make sure the intent is valid and give me a signed go/no-go.”
Technical details
Endpoint
POSThttps://api.oblique.markets/api/v1/paid/b402-preflightWhen to prefer
Use this endpoint when your agent needs a custody-free, signed validation of a BNB or BEP-20 payment intent before committing to an on-chain transaction on BNB Smart Chain. It is the right choice when you need to confirm intent freshness, recipient correctness, and payer balance in a single signed response without triggering any payment relay. Prefer this over generic blockchain RPC calls when you need a structured, decision-ready output compatible with the x402/B402 protocol flow.
Side effects
- Intent expired: deadline has passed, decision returns stale/invalid status
- Invalid recipient address: address fails checksum or format validation
- Chain not supported: unrecognized chain identifier returns 400 error
- Insufficient balance: payer BNB balance below specified amount (flagged in decision, not blocking)
- Malformed asset: unrecognized asset string or invalid BEP-20 contract address
- RPC/node unreachable: BNB chain query times out, returns 503 or error response
- Missing required fields: intent_id, recipient, or payer absent returns 422 validation error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| asset | string | native/BNB or a BEP-20 contract address |
| chain | string | |
| payer | string | |
| amount | string | |
| fee_cap | string | Maximum network fee in BNB |
| deadline | — | ISO-8601 timestamp or Unix seconds |
| intent_id | string | |
| recipient | string |
Output
Schema · Response
{
"type": "json",
"example": {
"asset": "BNB",
"chain": "eip155:56",
"payer": "0x1111111111111111111111111111111111111111",
"amount": "0.01",
"decision": "ready",
"intent_id": "invoice-2026-08-21-001",
"recipient": "0x2222222222222222222222222222222222222222",
"signature": "hmac-sha256:7a4e1c9b3d5f7a9c1e3b5d7f9a1c3e5b7d9f1a3c5e7b9d1f3a5c7e9b1d3f5a7",
"timestamp": "2026-08-21T20:00:00.000Z",
"fee_cap_bnb": "0.0005",
"intent_hash": "sha256:9c2d7b3f6e1a4c8b0d2e5f7a9b1c3d5e7f9a1b3c5d7e9f1a3b5c7d9e1f3a5b7c9",
"amount_units": "10000000000000000",
"asset_balance": "0.125",
"evidence_hash": "sha256:4e8f1a2c6d8b0f2e4a6c8e0f2a4c6e8f0a2c4e6f8a0b2c4d6e8f0a2c4e6f8a0b2",
"signing_key_id": "b402-preflight-v1",
"evidence_source": "public_bsc_rpc",
"recent_activity": {
"nonce": 42,
"latest_block": 61500000,
"lookback_blocks": 2000,
"incoming_transfer_count": 5,
"outgoing_transfer_count": 3
},
"recipient_valid": true,
"fee_headroom_bnb": "0.1245",
"fee_cap_sufficient": true
}
}Tags
x402
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