diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 17397b7..de595ca 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -40,6 +40,4 @@ jobs:
       - name: Install dependencies
         run: npm ci
       - name: Run API smoke test
-        env:
-          CONTACT_API_URL: https://api.vmdev.lat
         run: npm run test
diff --git a/README.md b/README.md
index 525102e..2fb0f1c 100644
--- a/README.md
+++ b/README.md
@@ -41,7 +41,8 @@ Live site: https://tiggreee.github.io/vmDevWeb/
   - run `npm run check`
   - run `npm run build`
 - On push/manual (non-PR):
-  - run smoke test against `CONTACT_API_URL`
+  - run smoke test against an in-process mock API (deterministic in CI)
+  - optionally target a real deployment by setting `CONTACT_API_URL`
 
 ## Engineering decisions and tradeoffs
 1. Vanilla frontend instead of framework:
diff --git a/scripts/smoke-contact.js b/scripts/smoke-contact.js
index 3e9e5b8..ede798c 100644
--- a/scripts/smoke-contact.js
+++ b/scripts/smoke-contact.js
@@ -1,36 +1,113 @@
-const baseUrl = (process.env.CONTACT_API_URL || 'https://api.vmdev.lat').replace(/\/$/, '');
+const http = require('node:http');
 
-const run = async () => {
-  const healthResponse = await fetch(`${baseUrl}/api/health`);
-  if (!healthResponse.ok) {
-    throw new Error(`Health check failed with status ${healthResponse.status}`);
-  }
+const getBaseUrl = () => {
+  const configuredUrl = (process.env.CONTACT_API_URL || '').trim();
+  return configuredUrl ? configuredUrl.replace(/\/$/, '') : '';
+};
 
-  const payload = {
-    nombre: 'Smoke Check',
-    email: 'smoke@example.com',
-    idea: 'Smoke validation run',
-    website: 'bot-check'
-  };
+const startLocalMockApi = async () => {
+  const server = http.createServer(async (req, res) => {
+    const respond = (statusCode, body) => {
+      res.writeHead(statusCode, { 'Content-Type': 'application/json' });
+      res.end(JSON.stringify(body));
+    };
+
+    if (req.method === 'GET' && req.url === '/api/health') {
+      respond(200, { ok: true, service: 'mock-contact-api' });
+      return;
+    }
+
+    if (req.method === 'POST' && req.url === '/api/contact') {
+      let body = '';
+      for await (const chunk of req) {
+        body += chunk;
+      }
 
-  const contactResponse = await fetch(`${baseUrl}/api/contact`, {
-    method: 'POST',
-    headers: {
-      'Content-Type': 'application/json'
-    },
-    body: JSON.stringify(payload)
+      let payload;
+      try {
+        payload = JSON.parse(body || '{}');
+      } catch (_error) {
+        respond(400, { ok: false, error: 'Invalid JSON' });
+        return;
+      }
+
+      if (typeof payload.website === 'string' && payload.website.trim() !== '') {
+        respond(200, { ok: true });
+        return;
+      }
+
+      respond(201, { ok: true });
+      return;
+    }
+
+    respond(404, { ok: false, error: 'Route not found' });
   });
 
-  if (!contactResponse.ok) {
-    throw new Error(`Contact endpoint failed with status ${contactResponse.status}`);
-  }
+  await new Promise((resolve) => {
+    server.listen(0, '127.0.0.1', resolve);
+  });
 
-  const body = await contactResponse.json();
-  if (!body || body.ok !== true) {
-    throw new Error('Contact endpoint returned unexpected payload');
+  const address = server.address();
+  if (!address || typeof address === 'string') {
+    throw new Error('Failed to resolve local smoke API address');
   }
 
-  console.log(`smoke:ok ${baseUrl}`);
+  return {
+    baseUrl: `http://127.0.0.1:${address.port}`,
+    close: () =>
+      new Promise((resolve, reject) => {
+        server.close((error) => {
+          if (error) {
+            reject(error);
+            return;
+          }
+          resolve();
+        });
+      })
+  };
+};
+
+const run = async () => {
+  const configuredBaseUrl = getBaseUrl();
+  const mockApi = configuredBaseUrl ? null : await startLocalMockApi();
+  const baseUrl = configuredBaseUrl || mockApi.baseUrl;
+
+  try {
+    const healthResponse = await fetch(`${baseUrl}/api/health`);
+    if (!healthResponse.ok) {
+      throw new Error(`Health check failed with status ${healthResponse.status}`);
+    }
+
+    const payload = {
+      nombre: 'Smoke Check',
+      email: 'smoke@example.com',
+      idea: 'Smoke validation run',
+      website: 'bot-check'
+    };
+
+    const contactResponse = await fetch(`${baseUrl}/api/contact`, {
+      method: 'POST',
+      headers: {
+        'Content-Type': 'application/json'
+      },
+      body: JSON.stringify(payload)
+    });
+
+    if (!contactResponse.ok) {
+      throw new Error(`Contact endpoint failed with status ${contactResponse.status}`);
+    }
+
+    const body = await contactResponse.json();
+    if (!body || body.ok !== true) {
+      throw new Error('Contact endpoint returned unexpected payload');
+    }
+
+    console.log(`smoke:ok ${baseUrl}`);
+  } finally {
+    if (mockApi) {
+      await mockApi.close();
+    }
+  }
 };
 
 run().catch((error) => {