When testing HTTPS connections with developer tools like Firebug or Chrome DevTools, many developers get confused seeing POST data in plaintext. This doesn't indicate a security breach - it's simply how debugging tools work. The crucial distinction lies between:

• Local visibility: What you see in browser dev tools
• Network transmission: What actually travels over the wire

Here's what happens during an HTTPS POST request:

// Client-side (browser) perspective
const response = await fetch('https://yoursite.com/api', {
  method: 'POST',
  body: JSON.stringify({ sensitive: 'data' }),
  headers: {
    'Content-Type': 'application/json'
  }
});

The encryption process:

1. SSL handshake establishes encrypted channel
2. POST data gets encrypted before leaving browser
3. Encrypted data travels through network
4. Server decrypts and processes

While corporate firewalls can inspect HTTPS traffic, they won't see plaintext POST data without:

• Installing custom CA certificates on client machines
• Performing MITM (man-in-the-middle) decryption

Typical firewall logs will show:

[HTTPS] 2023-08-20 14:30:45 POST /api - 200 OK
[HTTPS] 2023-08-20 14:31:02 GET /dashboard - 304 Not Modified

To confirm your implementation:

openssl s_client -connect yourdomain.com:443 -servername yourdomain.com \
  | openssl x509 -noout -text | grep "Subject Alternative Name"

For developers, using Wireshark with this filter helps verify encryption:

tcp.port == 443 && ip.addr == your.server.ip

Additional security measures:

// Server-side (Node.js example)
const https = require('https');
const fs = require('fs');

const options = {
  key: fs.readFileSync('server-key.pem'),
  cert: fs.readFileSync('server-cert.pem'),
  minVersion: 'TLSv1.2', // Enforce modern protocols
  ciphers: [
    'ECDHE-ECDSA-AES256-GCM-SHA384',
    'ECDHE-RSA-AES256-GCM-SHA384'
  ].join(':')
};

https.createServer(options, app).listen(443);

Remember that browser dev tools show pre-encryption data by design. For true end-to-end security, combine HTTPS with:

• HTTP Strict Transport Security (HSTS)
• Content Security Policy (CSP)
• Regular security headers audits

When testing HTTPS connections, developers often notice that browser tools like Firebug or Chrome DevTools display POST data in plaintext. This creates confusion - if SSL/TLS is working, why can we see the raw data?

// Example POST request visible in browser dev tools
POST /submit_form HTTP/1.1
Host: secure.example.com
Content-Type: application/x-www-form-urlencoded
Content-Length: 27

username=test&password=12345

The key clarification: browser dev tools show data after decryption. The encryption occurs during transmission between client and server. Here's what happens:

1. Browser encrypts all data using TLS before sending
2. Encrypted data travels through the network
3. Browser receives response and decrypts it
4. Dev tools display the decrypted content

While the end user sees plaintext in dev tools, network monitoring sees only encrypted data:

// What traverses the network (Wireshark example):
16 03 01 00 5a 02 00 00 56 03 01 4a 1b 2c 3d [...] 
[... hundreds of encrypted bytes ...]

Corporate firewalls typically see:

• Destination IP/port (usually 443)
• Domain via SNI (in plaintext)
• Encrypted payload (unreadable without private key)

To confirm your POST data is properly encrypted:

// PHP verification snippet
if ($_SERVER['HTTPS'] !== 'on') {
    die("Connection is not secure!");
}

// Or in Node.js/Express:
app.use((req, res, next) => {
    if (!req.secure) {
        return res.redirect('https://' + req.headers.host + req.url);
    }
    next();
});

While HTTPS generally protects POST data, be aware of:

Always implement HSTS to prevent downgrade attacks:

# Apache config
Header always set Strict-Transport-Security "max-age=63072000; includeSubDomains"