开发者文档

使用 Kem Business API 收取 USDT 付款所需的一切：身份认证、支付端点，以及驱动订单状态的签名 Webhooks。

身份认证

在仪表盘的「API 密钥」中创建密钥，并在每个请求中以 Bearer token 发送。测试密钥（sk_test_…）创建测试付款；正式密钥（sk_live_…）会转移真实资金。

Authorization: Bearer sk_live_...   # or sk_test_...
Base URL: https://api-business.kemapp.io

付款

创建付款并将客户引导至托管的 checkout_url——钱包、网络与确认全部由 Kem 处理。可通过查询付款跟踪状态，更推荐使用 Webhooks。

POST/v1/payments

curl -X POST https://api-business.kemapp.io/v1/payments \
  -H "Authorization: Bearer sk_test_..." \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: order-1042" \
  -d '{
    "amount": "25.000000",
    "currency": "USDT",
    "merchant_reference": "order-1042",
    "customer_email": "[email protected]",
    "description": "Pro plan",
    "return_url": "https://yourshop.example/thanks",
    "metadata": {"order_id": "1042"}
  }'

{
  "id": "pay_01J...",
  "status": "pending",
  "mode": "test",
  "amount": "25.000000",
  "amount_minor": 25000000,
  "amount_refunded_minor": 0,
  "fee_bps": null,
  "fee_minor": null,
  "net_minor": null,
  "currency": "USDT",
  "network": null,
  "merchant_reference": "order-1042",
  "checkout_url": "https://pay.kemapp.io/pay_01J...",
  "checkout_expires_at": "2026-07-13T13:30:00+00:00",
  "transaction_id": null,
  "detected_at": null,
  "confirmation_pending": false,
  "created_at": "2026-07-13T13:00:00+00:00",
  "updated_at": "2026-07-13T13:00:00+00:00"
}

Idempotency-Key — 可选但推荐——使用相同 key 重试会返回原付款，而不是创建重复项。

GET/v1/payments— query: status, limit (1–100, default 20), cursor · returns has_more, next_cursor

GET/v1/payments/{id}

amount — decimal string with 6 places ("25.000000"); amount_minor — the same value as an integer in micro-USDT.

fee_minor and net_minor are null while a payment is in flight and are frozen when it succeeds. Reconcile your payout against net_minor, not amount_minor — the difference is our fee (fee_bps).

付款生命周期

pending → detected → succeeded · failed · expired

pending——等待转账 · detected——链上已发现，确认中 · succeeded——资金已确认入账（在此事件发货）· failed / expired——终态。退款变更以 Webhook 事件送达。

checkout window: 30 minutes, then → expired

错误与限制

所有错误使用同一信封。code 是稳定的——请依据 error.code 分支，而不是文案。

HTTP 4xx/5xx
{
  "error": {
    "code": "idempotency_conflict",
    "message": "Idempotency-Key reused with a different request"
  }
}

401 unauthorized	missing or invalid API key
404 payment_not_found	unknown payment id (or a live id with a test key)
409 idempotency_conflict	Idempotency-Key reused with a different body — identical retries replay the original response
422 validation_error	malformed body — bad amount, unsupported currency. message reads “{field}: {reason}”
429 rate_limited	over the per-key budget: 100 writes/min, 1000 reads/min

产品、支付链接、Webhook 端点与退款均在仪表盘中管理——暂无公开 REST 端点。

Webhooks

在仪表盘「Webhooks」中添加端点并选择关注的事件。每个端点都有自己的 whsec_… 签名密钥，仅在创建时显示一次。

payment.created	A payment intent was created (API or checkout link).
payment.detected	The transfer was seen on-chain / in the KEM ledger; confirming.
payment.succeeded	Funds are confirmed in your business wallet. Fulfill on this event.
payment.failed	The payment failed.
payment.expired	The checkout window closed without payment.
payment.confirmation_delayed	The customer paid, but it couldn't be confirmed inside the checkout window. Don't treat this as expired — hold the order.
payment.refund.created	A refund was initiated from the dashboard.
payment.refund.succeeded	The refund settled back to the customer.

事件负载

{
  "id": "payment_event_01J...",
  "type": "payment.succeeded",
  "created": "2026-07-13T13:04:12+00:00",
  "data": {
    "payment": {
      "id": "pay_01J...",
      "status": "succeeded",
      "amount_minor": 25000000,
      "currency": "USDT",
      "merchant_reference": "order-1042",
      "network": "TRON",
      "product_id": null,
      "payment_link_id": null
    }
  }
}

验证签名

每次推送都带有 Kem-Signature 请求头。用端点密钥对「<t>.」加原始请求体重新计算 HMAC，并做恒定时间比较。不匹配的一律拒绝。

Kem-Signature: t=<unix_timestamp>,v1=<hmac_sha256_hex>

signed_input = "<t>." + raw_request_body
v1 = HMAC_SHA256(endpoint_secret, signed_input)   # secret: whsec_...

# reject replays: drop the delivery when |now - t| > 300s

import crypto from "node:crypto";

export function verifyKemSignature(rawBody, header, secret) {
  // header: "t=1720000000,v1=hex"
  const parts = Object.fromEntries(header.split(",").map((p) => p.split("=")));
  const expected = crypto
    .createHmac("sha256", secret)               // secret: whsec_...
    .update(`${parts.t}.`)
    .update(rawBody)                            // the RAW request bytes
    .digest("hex");
  return crypto.timingSafeEqual(Buffer.from(expected), Buffer.from(parts.v1));
}

import hashlib, hmac

def verify_kem_signature(raw_body: bytes, header: str, secret: str) -> bool:
    parts = dict(p.split("=") for p in header.split(","))
    expected = hmac.new(
        secret.encode(), f"{parts['t']}.".encode() + raw_body, hashlib.sha256
    ).hexdigest()
    return hmac.compare_digest(expected, parts["v1"])

投递与重试

请尽快返回 2xx。失败的投递会按退避策略重试，最终进入死信：

1m · 5m · 30m · 2h · 12h · 24h

测试

使用测试密钥可以在不转移资金的情况下走完付款全流程——模拟状态变更并观察你的 Webhooks 触发：

curl -X POST https://api-business.kemapp.io/v1/payments/{id}/_simulate/succeeded \
  -H "Authorization: Bearer sk_test_..."