diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index 74ed4eb..ae389f3 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -7,6 +7,7 @@ import Login from './pages/Login'
 import Register from './pages/Register'
 import Dashboard from './pages/Dashboard'
 import OpenApiDocs from './pages/OpenApiDocs'
+import ApiDebugger from './pages/ApiDebugger'
 import MerchantCenter from './pages/MerchantCenter'
 import PlatformMerchants from './pages/PlatformMerchants'
 import type { ReactNode } from 'react'
@@ -53,6 +54,14 @@ function AppRoutes() {
             </AdminRoute>
           }
         />
+        <Route
+          path="api-debug"
+          element={
+            <AdminRoute>
+              <ApiDebugger />
+            </AdminRoute>
+          }
+        />
       </Route>
       <Route path="*" element={<Navigate to="/" replace />} />
     </Routes>
diff --git a/frontend/src/layouts/MainLayout.tsx b/frontend/src/layouts/MainLayout.tsx
index 478ca15..6ffe89d 100644
--- a/frontend/src/layouts/MainLayout.tsx
+++ b/frontend/src/layouts/MainLayout.tsx
@@ -17,6 +17,7 @@ import {
   MenuUnfoldOutlined,
   ApiOutlined,
   ShopOutlined,
+  BugOutlined,
 } from '@ant-design/icons'
 import { useAuth } from '../store/auth'
 import type { MenuProps } from 'antd'
@@ -42,6 +43,11 @@ export default function MainLayout() {
         { key: '/platform-merchants', icon: <ShopOutlined />, label: '商户管理' },
         { key: '/open-api', icon: <ApiOutlined />, label: '开放接口' },
       )
+      if (import.meta.env.DEV) {
+        items.push(
+          { key: '/api-debug', icon: <BugOutlined />, label: 'API 调试' },
+        )
+      }
     }
     return items
   }, [isAdmin])
diff --git a/frontend/src/pages/ApiDebugger.tsx b/frontend/src/pages/ApiDebugger.tsx
new file mode 100644
index 0000000..4479475
--- /dev/null
+++ b/frontend/src/pages/ApiDebugger.tsx
@@ -0,0 +1,470 @@
+import { useCallback, useEffect, useMemo, useState } from 'react'
+import {
+  Alert,
+  Button,
+  Card,
+  Descriptions,
+  Form,
+  Input,
+  message,
+  Radio,
+  Space,
+  Spin,
+  Tag,
+  Typography,
+} from 'antd'
+import { ClearOutlined, SendOutlined } from '@ant-design/icons'
+import { endpoints } from '../openapi/endpoints'
+
+const STORAGE_KEY_APP = 'api_debug_app_key'
+const STORAGE_KEY_SECRET = 'api_debug_secret'
+
+const { Title, Text, Paragraph } = Typography
+const { TextArea } = Input
+
+const methodColor: Record<string, string> = {
+  GET: 'blue',
+  POST: 'green',
+  PUT: 'orange',
+  PATCH: 'gold',
+  DELETE: 'red',
+}
+
+async function hmacSha256Hex(secret: string, data: string): Promise<string> {
+  const enc = new TextEncoder()
+  const key = await crypto.subtle.importKey(
+    'raw',
+    enc.encode(secret),
+    { name: 'HMAC', hash: 'SHA-256' },
+    false,
+    ['sign'],
+  )
+  const sig = await crypto.subtle.sign('HMAC', key, enc.encode(data))
+  return Array.from(new Uint8Array(sig))
+    .map((b) => b.toString(16).padStart(2, '0'))
+    .join('')
+}
+
+async function sha256Hex(data: Uint8Array): Promise<string> {
+  const hash = await crypto.subtle.digest('SHA-256', data as BufferSource)
+  return Array.from(new Uint8Array(hash))
+    .map((b) => b.toString(16).padStart(2, '0'))
+    .join('')
+}
+
+function buildSignString(
+  appKey: string,
+  bodyHash: string,
+  method: string,
+  nonce: string,
+  path: string,
+  timestamp: string,
+) {
+  return [
+    `app_key=${appKey}`,
+    `body_sha256=${bodyHash}`,
+    `method=${method.toUpperCase()}`,
+    `nonce=${nonce}`,
+    `path=${path}`,
+    `timestamp=${timestamp}`,
+  ].join('&')
+}
+
+export default function ApiDebugger() {
+  const [appKey, setAppKey] = useState(() => localStorage.getItem(STORAGE_KEY_APP) ?? '')
+  const [secret, setSecret] = useState(() => localStorage.getItem(STORAGE_KEY_SECRET) ?? '')
+  const [selectedKey, setSelectedKey] = useState<string>(endpoints[0]?.key ?? '')
+  const [pathValues, setPathValues] = useState<Record<string, string>>({})
+  const [queryValues, setQueryValues] = useState<Record<string, string>>({})
+  const [bodyText, setBodyText] = useState('')
+  const [idempotencyKey, setIdempotencyKey] = useState('')
+  const [loading, setLoading] = useState(false)
+
+  const handleAppKeyChange = (val: string) => {
+    setAppKey(val)
+    localStorage.setItem(STORAGE_KEY_APP, val)
+  }
+
+  const handleSecretChange = (val: string) => {
+    setSecret(val)
+    localStorage.setItem(STORAGE_KEY_SECRET, val)
+  }
+
+  const handleForget = () => {
+    localStorage.removeItem(STORAGE_KEY_APP)
+    localStorage.removeItem(STORAGE_KEY_SECRET)
+    setAppKey('')
+    setSecret('')
+  }
+
+  const [response, setResponse] = useState<{
+    status: number
+    headers: Record<string, string>
+    body: string
+    elapsed: number
+  } | null>(null)
+
+  const [signInfo, setSignInfo] = useState<{
+    timestamp: string
+    nonce: string
+    signString: string
+    signature: string
+    path: string
+    query: string
+  } | null>(null)
+
+  const endpoint = endpoints.find((e) => e.key === selectedKey)
+  const isCreateOrder = selectedKey === 'create-order'
+
+  useEffect(() => {
+    if (endpoint?.requestExample) {
+      try {
+        JSON.parse(endpoint.requestExample)
+        setBodyText(endpoint.requestExample)
+      } catch {
+        setBodyText('')
+      }
+    } else {
+      setBodyText('')
+    }
+    setPathValues({})
+    setQueryValues({})
+    setIdempotencyKey('')
+    setResponse(null)
+    setSignInfo(null)
+  }, [selectedKey, endpoint])
+
+  const buildPath = useCallback(() => {
+    if (!endpoint) return ''
+    let p = endpoint.path
+    for (const key of Object.keys(pathValues)) {
+      if (pathValues[key]) {
+        p = p.replace(`{${key}}`, pathValues[key])
+      }
+    }
+    return p
+  }, [endpoint, pathValues])
+
+  const buildQuery = useCallback(() => {
+    const p = new URLSearchParams()
+    for (const key of Object.keys(queryValues)) {
+      if (queryValues[key]) p.append(key, queryValues[key])
+    }
+    const qs = p.toString()
+    return qs ? `?${qs}` : ''
+  }, [queryValues])
+
+  const readyPath = useMemo(() => buildPath(), [buildPath])
+  const readyQuery = useMemo(() => buildQuery(), [buildQuery])
+
+  const handleSend = async () => {
+    if (!appKey.trim() || !secret.trim()) {
+      message.error('请先填写 AppKey 和 Secret')
+      return
+    }
+    if (!endpoint) return
+
+    const enc = new TextEncoder()
+    const bodyBytes = enc.encode(bodyText)
+    const timestamp = String(Math.floor(Date.now() / 1000))
+    const nonce = crypto.randomUUID().replace(/-/g, '').substring(0, 16)
+    const bodyHash = await sha256Hex(bodyBytes)
+    const method = endpoint.method
+    const plainPath = readyPath
+    const signString = buildSignString(appKey.trim(), bodyHash, method, nonce, plainPath, timestamp)
+    const signature = await hmacSha256Hex(secret.trim(), signString)
+
+    setSignInfo({
+      timestamp,
+      nonce,
+      signString,
+      signature,
+      path: plainPath,
+      query: readyQuery,
+    })
+
+    const fetchHeaders: Record<string, string> = {
+      'X-App-Key': appKey.trim(),
+      'X-Timestamp': timestamp,
+      'X-Nonce': nonce,
+      'X-Sign': signature,
+    }
+    if (method !== 'GET' && bodyText) {
+      fetchHeaders['Content-Type'] = 'application/json'
+    }
+    if (isCreateOrder && idempotencyKey.trim()) {
+      fetchHeaders['Idempotency-Key'] = idempotencyKey.trim()
+    }
+
+    setLoading(true)
+    const start = performance.now()
+    try {
+      const res = await fetch(plainPath + readyQuery, {
+        method,
+        headers: fetchHeaders,
+        body: method === 'GET' ? undefined : bodyText,
+      })
+      const elapsed = Math.round(performance.now() - start)
+      const resBody = await res.text()
+      const resHeaders: Record<string, string> = {}
+      res.headers.forEach((v, k) => {
+        resHeaders[k] = v
+      })
+      setResponse({ status: res.status, headers: resHeaders, body: resBody, elapsed })
+    } catch (err: unknown) {
+      const msg = err instanceof Error ? err.message : String(err)
+      setResponse({
+        status: 0,
+        headers: {},
+        body: `请求失败: ${msg}`,
+        elapsed: Math.round(performance.now() - start),
+      })
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  const formatJSON = (raw: string) => {
+    try {
+      return JSON.stringify(JSON.parse(raw), null, 2)
+    } catch {
+      return raw
+    }
+  }
+
+  return (
+    <div>
+      <Title level={4} style={{ marginTop: 0 }}>
+        API 调试工具
+      </Title>
+      <Paragraph type="secondary">
+        填写商户 API 客户端的 AppKey 与 Secret，选择接口并发送请求。签名在浏览器端使用 Web Crypto API 计算。
+      </Paragraph>
+
+      {!import.meta.env.DEV && (
+        <Alert
+          type="warning"
+          showIcon
+          message="当前为生产构建，调试工具仅开发模式可用。"
+          style={{ marginBottom: 16 }}
+        />
+      )}
+
+      <Card
+        title="凭证"
+        style={{ marginBottom: 20 }}
+        extra={
+          <Button danger onClick={handleForget} disabled={!appKey && !secret}>
+            忘记凭证
+          </Button>
+        }
+      >
+        <Space wrap size="middle">
+          <Input
+            placeholder="AppKey"
+            value={appKey}
+            onChange={(e) => handleAppKeyChange(e.target.value)}
+            style={{ width: 320 }}
+            allowClear
+            size="middle"
+          />
+          <Input.Password
+            placeholder="Secret"
+            value={secret}
+            onChange={(e) => handleSecretChange(e.target.value)}
+            style={{ width: 400 }}
+            allowClear
+            size="middle"
+          />
+        </Space>
+      </Card>
+
+      <Card
+        title="选择接口"
+        style={{ marginBottom: 20 }}
+        extra={
+          <Button
+            type="primary"
+            icon={<SendOutlined />}
+            loading={loading}
+            onClick={handleSend}
+            disabled={!appKey.trim() || !secret.trim()}
+            size="middle"
+          >
+            发送请求
+          </Button>
+        }
+      >
+        <Radio.Group
+          value={selectedKey}
+          onChange={(e) => setSelectedKey(e.target.value)}
+          style={{ width: '100%', display: 'block' }}
+        >
+          {endpoints.map((ep) => (
+            <div
+              key={ep.key}
+              style={{
+                padding: '10px 14px',
+                marginBottom: 8,
+                border: selectedKey === ep.key ? '1px solid #1677ff' : '1px solid #f0f0f0',
+                borderRadius: 8,
+                background: selectedKey === ep.key ? '#f0f5ff' : '#fff',
+                cursor: 'pointer',
+                transition: 'all 0.2s',
+              }}
+              onClick={() => setSelectedKey(ep.key)}
+            >
+              <Radio value={ep.key} style={{ marginRight: 12 }} />
+              <Tag color={methodColor[ep.method]} style={{ fontWeight: 700, fontSize: 13 }}>
+                {ep.method}
+              </Tag>
+              <Text code style={{ fontSize: 14, marginRight: 12 }}>{ep.path}</Text>
+              <Text type="secondary" style={{ fontSize: 13 }}>{ep.summary}</Text>
+            </div>
+          ))}
+        </Radio.Group>
+      </Card>
+
+      {endpoint && (
+        <Card title="请求参数" style={{ marginBottom: 20 }}>
+          <Form layout="vertical">
+            {endpoint.pathParams?.map((p) => (
+              <Form.Item key={p.name} label={<Text code style={{ fontSize: 14 }}>{`{${p.name}}`}</Text>} help={p.desc}>
+                <Input
+                  placeholder={p.example ?? p.desc}
+                  value={pathValues[p.name] ?? ''}
+                  onChange={(e) => setPathValues((prev) => ({ ...prev, [p.name]: e.target.value }))}
+                  style={{ maxWidth: 480 }}
+                />
+              </Form.Item>
+            ))}
+
+            {endpoint.queryParams?.map((p) => (
+              <Form.Item key={p.name} label={<Text code style={{ fontSize: 14 }}>{p.name}</Text>} help={p.desc}>
+                <Input
+                  placeholder={p.example ?? p.desc}
+                  value={queryValues[p.name] ?? ''}
+                  onChange={(e) => setQueryValues((prev) => ({ ...prev, [p.name]: e.target.value }))}
+                  style={{ maxWidth: 240 }}
+                />
+              </Form.Item>
+            ))}
+
+            {endpoint.method !== 'GET' && (
+              <Form.Item
+                label={
+                  <Space>
+                    <Text strong style={{ fontSize: 14 }}>Request Body (JSON)</Text>
+                    <Button size="small" icon={<ClearOutlined />} onClick={() => setBodyText('')}>清空</Button>
+                    {endpoint.requestExample && (
+                      <Button size="small" onClick={() => setBodyText(endpoint.requestExample!)}>填入示例</Button>
+                    )}
+                  </Space>
+                }
+              >
+                <TextArea
+                  rows={10}
+                  value={bodyText}
+                  onChange={(e) => setBodyText(e.target.value)}
+                  style={{ fontFamily: 'monospace', fontSize: 13, lineHeight: 1.5 }}
+                  placeholder={endpoint.requestExample ?? '{}'}
+                />
+              </Form.Item>
+            )}
+
+            {isCreateOrder && (
+              <Form.Item label={<Text code style={{ fontSize: 14 }}>Idempotency-Key</Text>} help="须与 client_order_no 一致">
+                <Input
+                  value={idempotencyKey}
+                  onChange={(e) => setIdempotencyKey(e.target.value)}
+                  style={{ maxWidth: 480 }}
+                  placeholder="会从 Request Body 自动取 client_order_no"
+                />
+              </Form.Item>
+            )}
+          </Form>
+
+          <Alert
+            type="info"
+            message={
+              <span style={{ fontSize: 14 }}>
+                <Tag color={methodColor[endpoint.method]} style={{ fontWeight: 700 }}>{endpoint.method}</Tag>
+                <Text code style={{ fontSize: 13 }}>{readyPath + readyQuery}</Text>
+              </span>
+            }
+          />
+        </Card>
+      )}
+
+      {signInfo && (
+        <Card title="签名详情" style={{ marginBottom: 20 }}>
+          <Descriptions column={1} bordered>
+            <Descriptions.Item label="X-Timestamp">{signInfo.timestamp}</Descriptions.Item>
+            <Descriptions.Item label="X-Nonce">{signInfo.nonce}</Descriptions.Item>
+            <Descriptions.Item label="X-App-Key">{appKey.trim()}</Descriptions.Item>
+            <Descriptions.Item label="签名串">
+              <pre style={{ margin: 0, fontSize: 13, whiteSpace: 'pre-wrap', wordBreak: 'break-all' }}>
+                {signInfo.signString}
+              </pre>
+            </Descriptions.Item>
+            <Descriptions.Item label="X-Sign">
+              <Text code copyable style={{ fontSize: 13 }}>{signInfo.signature}</Text>
+            </Descriptions.Item>
+          </Descriptions>
+        </Card>
+      )}
+
+      {response && (
+        <Card
+          title="响应"
+          extra={
+            <Space size="middle">
+              <Tag color={response.status >= 200 && response.status < 300 ? 'green' : 'red'}>
+                {response.status || 'ERR'}
+              </Tag>
+              <Text type="secondary">{response.elapsed}ms</Text>
+            </Space>
+          }
+        >
+          <Spin spinning={loading}>
+            <div style={{ fontSize: 14, fontWeight: 500, margin: '8px 0 6px' }}>Response Headers</div>
+            <pre
+              style={{
+                margin: 0,
+                padding: 10,
+                background: '#f6f8fa',
+                borderRadius: 6,
+                fontSize: 12,
+                lineHeight: 1.6,
+                maxHeight: 200,
+                overflow: 'auto',
+              }}
+            >
+              {Object.entries(response.headers)
+                .map(([k, v]) => `${k}: ${v}`)
+                .join('\n') || '(无)'}
+            </pre>
+
+            <div style={{ fontSize: 14, fontWeight: 500, margin: '16px 0 6px' }}>Response Body</div>
+            <pre
+              style={{
+                margin: 0,
+                padding: 14,
+                background: '#f6f8fa',
+                borderRadius: 6,
+                fontSize: 13,
+                lineHeight: 1.6,
+                maxHeight: 600,
+                overflow: 'auto',
+                whiteSpace: 'pre-wrap',
+                wordBreak: 'break-all',
+              }}
+            >
+              {formatJSON(response.body)}
+            </pre>
+          </Spin>
+        </Card>
+      )}
+    </div>
+  )
+}