diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..5d47c21
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,12 @@
+# EditorConfig is awesome: https://EditorConfig.org
+
+# top-most EditorConfig file
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 0000000..38163df
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,17 @@
+{
+  "deno.codeLens.implementations": true,
+  "deno.codeLens.referencesAllFunctions": true,
+  "deno.codeLens.references": true,
+  "deno.codeLens.test": true,
+  "deno.enable": true,
+  "deno.config": "./deno.json",
+  "deno.lint": true,
+  "editor.defaultFormatter": "esbenp.prettier-vscode",
+  "[typescript]": {
+    "editor.defaultFormatter": "denoland.vscode-deno"
+  },
+  "editor.formatOnSave": true,
+  "[sql]": {
+    "editor.formatOnSave": false
+  }
+}
diff --git a/README.md b/README.md
index c1864a0..965b945 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,23 @@ A Node.js program use dns.he.net as DDNS service.
 
 ## Configuration
 
+```sh
+OPTIONS:
+
+-d, --domain
+        Set domain
+
+-t, --token
+        Set he.net auth token
+
+    --delaytime
+        Set loop delay time, ms.
+
+-h, --help
+```
+
 Set env:
 
 - USEDDNS_DOMAIN
 - USEDDNS_HE_TOKEN
+- [OPTION] USEDDNS_DELAY_TIME
diff --git a/deno.json b/deno.json
new file mode 100644
index 0000000..8a8cc6f
--- /dev/null
+++ b/deno.json
@@ -0,0 +1,40 @@
+{
+  "compilerOptions": {
+    "strict": true
+  },
+  "lint": {
+    "files": {
+      "include": [
+        "src/",
+        "mod.ts"
+      ]
+    },
+    "rules": {
+      "tags": [
+        "recommended"
+      ],
+      "include": [
+        "eqeqeq",
+        "explicit-module-boundary-types",
+        "no-throw-literal"
+      ],
+      "exclude": [
+        "ban-unused-ignore"
+      ]
+    }
+  },
+  "fmt": {
+    "files": {
+      "include": [
+        "src/",
+        "mod.ts"
+      ]
+    },
+    "options": {
+      "useTabs": false,
+      "lineWidth": 80,
+      "indentWidth": 2,
+      "singleQuote": true
+    }
+  }
+}
diff --git a/src/cli.ts b/src/cli.ts
new file mode 100644
index 0000000..ffbb1a5
--- /dev/null
+++ b/src/cli.ts
@@ -0,0 +1,62 @@
+import { parse } from 'https://deno.land/std@0.161.0/flags/mod.ts';
+import { checkIP } from './useddns.ts';
+
+const args = parse<
+  Partial<
+    {
+      d: string;
+      domain: string;
+      t: string;
+      token: string;
+      delaytime: number;
+      h: boolean;
+      help: boolean;
+    }
+  >
+>(
+  Deno.args,
+);
+
+const isHelp = args.h ?? args.help;
+if (isHelp) {
+  console.log(`
+OPTIONS:
+
+-d, --domain
+        Set domain
+
+-t, --token
+        Set he.net auth token
+
+    --delaytime
+        Set loop delay time, ms.
+
+-h, --help`);
+  Deno.exit();
+}
+
+const domain = args.d ?? args.domain ?? Deno.env.get('USEDDNS_DOMAIN');
+const token = args.t ?? args.token ?? Deno.env.get('USEDDNS_HE_TOKEN');
+const delay = Number(
+  args.delaytime ?? Deno.env.get('USEDDNS_DELAY_TIME') ?? 5000,
+);
+
+if (!domain || !token) {
+  throw new Error(
+    'Please set cli args or configure environment variables first.',
+  );
+}
+
+console.log({ domain, token });
+
+setInterval(async () => {
+  const [err, res] = await checkIP(token, domain);
+  const d = new Date();
+  if (err) {
+    console.error(d, err);
+  } else {
+    if (res !== 'eq') {
+      console.log(d, res);
+    }
+  }
+}, delay);
diff --git a/src/useddns.test.ts b/src/useddns.test.ts
new file mode 100644
index 0000000..42b60fa
--- /dev/null
+++ b/src/useddns.test.ts
@@ -0,0 +1,17 @@
+import { assert } from 'https://deno.land/std@0.161.0/testing/asserts.ts';
+import { getCurrentIP, getDNSIP } from './useddns.ts';
+
+Deno.test('getCurrentIP', async () => {
+  const res = await getCurrentIP();
+  console.log(res);
+  assert(res.length > 0);
+});
+
+Deno.test('getDNSIP', async () => {
+  const res = await getDNSIP(
+    'www.google.com',
+    { dns: '1.1.1.1' },
+  );
+  console.log(res);
+  assert(res.length > 0);
+});
diff --git a/src/useddns.ts b/src/useddns.ts
new file mode 100644
index 0000000..7ef40ea
--- /dev/null
+++ b/src/useddns.ts
@@ -0,0 +1,51 @@
+import { run } from 'https://deno.land/x/somefn@v0.20.0/deno/run.ts';
+
+export async function getIP(params: string): Promise<string> {
+  const { res } = await run(`dig ${params} +short -4`);
+  return res.replace(/(\r\n|\n|\r)/gm, '');
+}
+
+export function getCurrentIP(): Promise<string> {
+  return getIP('@ns1-1.akamaitech.net ANY whoami.akamai.net');
+}
+
+export function getDNSIP(
+  domain: string,
+  { dns = '1.1.1.1' }: { dns?: string } = {},
+): Promise<string> {
+  return getIP(`@${dns} A ${domain}`);
+}
+
+export async function checkIP(
+  token: string,
+  domain: string,
+): Promise<[err: Error] | [err: null, res: string]> {
+  try {
+    const currentIP = await getCurrentIP();
+    const DNSIP = await getDNSIP(domain);
+    if (!currentIP || !DNSIP) {
+      throw new Error(
+        'Did not get IP: ' + JSON.stringify({ currentIP, DNSIP }),
+      );
+    }
+    if (currentIP !== DNSIP) {
+      console.log(JSON.stringify({ currentIP, DNSIP }));
+      const url = new URL('https://dyn.dns.he.net/nic/update');
+      url.searchParams.set('hostname', domain);
+      url.searchParams.set('password', token);
+      url.searchParams.set('myip', currentIP);
+      const res = await fetch(
+        url,
+        { method: 'GET' },
+      );
+      console.log('res', res.status, res.headers, await res.text());
+      return [null, await res.text()];
+    }
+    return [null, 'eq'];
+  } catch (err) {
+    if (err instanceof Error) {
+      return [err];
+    }
+    return [new Error(`unknown ${err}`)];
+  }
+}