Server and webhooks

@chinafast/server-wechat-pay creates App, H5, JSAPI, and Native QR orders; queries and closes orders; submits refunds; and verifies API v3 webhooks.

Live configuration

import { createWeChatPayServer } from "@chinafast/server-wechat-pay";

const wechatPay = createWeChatPayServer({
  mode: "live",
  credentials: {
    appId: process.env.WECHAT_APP_ID!,
    merchantId: process.env.WECHAT_MERCHANT_ID!,
    apiV3Key: process.env.WECHAT_API_V3_KEY!,
    privateKey: process.env.WECHAT_PRIVATE_KEY!.replace(/\\n/g, "\n"),
    certificateSerialNo: process.env.WECHAT_CERTIFICATE_SERIAL_NO!,
    platformCertificates: {
      [process.env.WECHAT_PLATFORM_SERIAL!]:
        process.env.WECHAT_PLATFORM_CERTIFICATE!.replace(/\\n/g, "\n"),
    },
    notifyUrl: "https://api.example.com/wechat-pay/webhook",
  },
});

Webhook handling

Pass the exact raw HTTP request body and WeChat signature headers to verifyWebhook. Parsing JSON and serializing it again changes the signed bytes and invalidates verification.

Only fulfil after all of these checks succeed:

• The webhook signature matches a trusted, current WeChat platform certificate.
• The encrypted resource decrypts and parses successfully.
• The merchant ID and app ID match the expected account.
• The order ID exists and its amount and currency match your server-side record.
• The same event or order has not already been fulfilled.

Use an idempotent database transaction to record payment and grant the purchased product together. Webhooks can be retried, duplicated, delayed, or arrive out of order.

Client status is not payment proof

Native callbacks, browser redirects, and JSAPI results are useful for interface state only. Your server should use a verified webhook or an authenticated order query as the source of truth.