Heroku Integration

Heroku runs your app on dynos and supports any Node.js server. Integrating SeoRend is straightforward using the Express middleware approach.

How It Works

Your Heroku app adds SeoRend middleware that intercepts bot requests before they reach your frontend. Since Heroku has full Node.js support, no additional configuration is needed beyond setting an environment variable.

Requirements

• Heroku account with a deployed app
• Node.js app (Express, Fastify, or similar)
• SeoRend API key from app.seorend.com

1. Set the environment variable

   Using Heroku CLI:

   heroku config:set SEOREND_API_KEY=sk_live_your_key_here --app your-app-name

   Or go to Heroku Dashboard → Settings → Config Vars → Reveal Config Vars and add SEOREND_API_KEY.

2. Add SeoRend middleware

   If your app uses Express, add the middleware before your static file serving:

   server.js

   const express = require('express');
   const app = express();
   
   // Bot detection patterns
   const BOT_PATTERNS = [
     'googlebot', 'bingbot', 'yandexbot', 'duckduckbot', 'applebot',
     'facebookexternalhit', 'twitterbot', 'linkedinbot', 'slackbot',
     'gptbot', 'claudebot', 'perplexitybot', 'google-extended', 'ccbot',
     'semrushbot', 'ahrefsbot', 'rogerbot',
   ];
   
   const STATIC_EXT = /\.(js|css|png|jpg|gif|ico|svg|webp|woff2?|pdf|mp4)$/i;
   
   function isBot(ua) {
     const lower = (ua || '').toLowerCase();
     return BOT_PATTERNS.some(p => lower.includes(p));
   }
   
   // SeoRend middleware — must be registered before static serving
   app.use(async (req, res, next) => {
     const ua = req.headers['user-agent'] || '';
   
     if (req.method !== 'GET') return next();
     if (STATIC_EXT.test(req.path)) return next();
     if (!isBot(ua)) return next();
   
     const apiKey = process.env.SEOREND_API_KEY;
     if (!apiKey) return next();
   
     const url = `${req.protocol}://${req.get('host')}${req.originalUrl}`;
   
     try {
       const response = await fetch('https://render.seorend.com/v1/render', {
         method: 'POST',
         headers: {
           'Content-Type': 'application/json',
           'Authorization': `Bearer ${apiKey}`,
         },
         body: JSON.stringify({ url, userAgent: ua }),
       });
   
       if (!response.ok) return next();
   
       const data = await response.json();
       res.set('Content-Type', 'text/html; charset=utf-8');
       res.set('X-Seorend-Cache', data.cache?.hit ? 'HIT' : 'MISS');
       return res.status(data.status || 200).send(data.html);
     } catch {
       return next();
     }
   });
   
   // Serve your React/Vue/Angular app
   app.use(express.static('build'));
   app.get('*', (req, res) => {
     res.sendFile('index.html', { root: 'build' });
   });
   
   const PORT = process.env.PORT || 3000;
   app.listen(PORT, () => console.log(`Listening on port ${PORT}`));

   Note

   Heroku sets the PORT environment variable automatically. Always use process.env.PORT — don’t hardcode a port number.

3. Deploy

   git add .
   git commit -m "Add SeoRend prerendering middleware"
   git push heroku main

4. Verify

   heroku logs --tail --app your-app-name

   Then test:

   curl -s -I -A "Googlebot/2.1" https://your-app.herokuapp.com/
   # Should see: X-Seorend-Cache: MISS (first request) or HIT

Heroku Review Apps

If you use Heroku Review Apps, set SEOREND_API_KEY in your app.json to automatically include it in review app environments:

app.json

{
  "env": {
    "SEOREND_API_KEY": {
      "description": "SeoRend API key for bot prerendering",
      "required": true
    }
  }
}

Heroku eco dynos and cold starts

On Heroku eco or basic dynos, your app may sleep after 30 minutes of inactivity. Use Warm Bot to keep your important pages cached — even if a dyno is cold when a bot arrives, SeoRend will serve the cached HTML.

Troubleshooting

fetch not available: Node.js 18+ includes fetch globally. If you’re on Node.js 16, add node-fetch:

npm install node-fetch

And import it: const fetch = require('node-fetch');

Config var not set: Run heroku config --app your-app-name to verify SEOREND_API_KEY is present.

Next Steps

• Testing guide — verify the integration
• Warm Bot — keep pages warm for sleepy dynos