diff --git a/dev/admin.htm b/dev/admin.htm
new file mode 100644
index 0000000..e76621b
--- /dev/null
+++ b/dev/admin.htm
@@ -0,0 +1,98 @@
+<!doctype html>
+<html>
+  <head>
+    <script>
+function status(msg) {
+  document.getElementById('status').textContent = msg
+}
+async function queryParams() {
+  const req = await fetch('/api/params')
+  const json = await req.json()
+  //console.log(json)
+  //console.log(Object.keys(json))
+  status('parameter query successful!')
+  const paramList = document.getElementById('param-list')
+  while (paramList.firstChild) {
+    paramList.removeChild(paramList.lastChild)
+  }
+  Object.keys(json).forEach((name) => {
+    const elem = document.createElement('div')
+    elem.textContent = name + " = " + json[name]
+    paramList.appendChild(elem)
+  })
+}
+
+async function setParam(auth, name, value) {
+  const msg = JSON.stringify({
+    auth: auth,
+    data: {
+      set_params: {
+        name: name,
+        value: value
+      }
+    }
+  })
+  console.log('set param fetch pre')
+  const resp = await fetch('/api/admin', {
+    method: 'POST',
+    body: msg
+  })
+  console.log('set param fetch post')
+  if (!resp.ok) {
+    var err_msg = null
+    if (resp.body != null) {
+      err_msg = await resp.text()
+    }
+    if (err_msg != null) {
+      status("set failed: " + resp.status + " " + err_msg)
+    } else {
+      status("set failed: " + resp.status)
+    }
+  } else {
+    status("parameter set successful!")
+    await queryParams()
+  }
+}
+
+window.onload = () => {
+  document.getElementById('query-params').addEventListener('click', (e) => {
+    queryParams()
+  })
+
+  document.getElementById('set-param').addEventListener('click', (e) => {
+    const auth = document.getElementById('password').value
+    const name = document.getElementById('name').value
+    const value = parseFloat(document.getElementById('value').value)
+    if (isNaN(value)) {
+      status('invalid value set')
+      return
+    }
+    setParam(auth, name, value)
+  })
+}
+    </script>
+  </head>
+  <body>
+    <fieldset>
+      <legend>Status</legend>
+      <div id=status></div>
+    </fieldset>
+    <form>
+      <fieldset>
+        <legend>Parameter list</legend>
+        <div id=param-list></div>
+        <input id=query-params type=button value="Query params"></input><br />
+      </fieldset>
+      <label for=password>Auth password: </label>
+      <input id=password type=password></input><br />
+      <fieldset>
+        <legend>Set parameter</legend>
+        <label for=name>Name: </label>
+        <input id=name type=text></input><br />
+        <label for=value>Value: </label>
+        <input id=value type=text></input><br />
+        <input id=set-param type=button value="Set parameter"></input><br />
+      </fieldset>
+    </form>
+  </body>
+</html>
