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Network & CORS Issues

Solutions for connectivity problems, CORS errors, and network-related issues.

CORS Errors​

Symptoms​

  • Browser console shows CORS errors
  • "Access-Control-Allow-Origin" errors
  • Requests blocked by browser
  • Works in Node.js but not browser

Understanding CORS​

CORS (Cross-Origin Resource Sharing) is a browser security feature. It only affects browser-based applications, not server-side code.

Solutions​

1. Verify You're Using the Right Endpoint​

Toggly provides different endpoints:

// ✅ For browser/client-side apps (definitions worker, CORS-enabled)
const toggly = new TogglyClient({
  appKey: 'your-key',
  environment: 'production',
  baseURL: 'https://definitions.toggly.io'
});

// ✅ For server-side apps (same host; CORS not required)
const toggly = new TogglyClient({
  appKey: 'your-key',
  environment: 'production',
  baseURL: 'https://definitions.toggly.io'
});

2. Use Client-Side SDK​

For browser apps, always use the client-side SDK:

  • @ops-ai/feature-flags-toggly for vanilla JS
  • @ops-ai/react-feature-flags-toggly for React
  • @ops-ai/ngx-feature-flags-toggly for Angular
  • @ops-ai/vue-feature-flags-toggly for Vue

These SDKs are pre-configured with the correct endpoints.

3. Proxy Requests (If Needed)​

For SSR frameworks like Next.js or Nuxt:

// api/toggly-proxy.ts
export default async function handler(req, res) {
  const response = await fetch('https://definitions.toggly.io/evaluated-signed/...', {
    headers: {
      'Authorization': `Bearer ${process.env.TOGGLY_API_KEY}`
    }
  });
  const data = await response.json();
  res.json(data);
}

Network Timeout​

Symptoms​

  • Requests take too long
  • "Network timeout" errors
  • SDK initialization hangs
  • Intermittent connectivity

Solutions​

1. Increase Timeout​

const toggly = new TogglyClient({
  appKey: 'your-key',
  environment: 'production',
  timeout: 10000, // 10 seconds (default is 5s)
});

2. Check Network Connectivity​

# Test connectivity to Toggly
curl -I https://definitions.toggly.io

# Check DNS resolution
nslookup definitions.toggly.io

3. Verify Firewall/Proxy​

Corporate firewalls may block requests:

  • Check with IT department
  • Whitelist *.toggly.io domains
  • Configure proxy settings if required
// Configure proxy (Node.js)
const toggly = new TogglyClient({
  appKey: 'your-key',
  environment: 'production',
  proxy: {
    host: 'proxy.company.com',
    port: 8080,
  }
});

SSL/TLS Errors​

Symptoms​

  • "SSL certificate verification failed"
  • "CERT_HAS_EXPIRED" errors
  • "unable to verify the first certificate"

Solutions​

1. Update Node.js/Runtime​

Older versions may have outdated SSL certificates:

# Check Node.js version
node --version

# Update to latest LTS
nvm install --lts
nvm use --lts

2. Update CA Certificates​

# Ubuntu/Debian
sudo apt-get update
sudo apt-get install ca-certificates

# macOS
brew install ca-certificates

3. Check System Time​

Incorrect system time can cause SSL errors:

# Verify system time is correct
date

# Update if needed (varies by OS)

DNS Resolution Issues​

Symptoms​

  • "getaddrinfo ENOTFOUND" errors
  • Can't resolve toggly.io domains
  • Works on one network but not another

Solutions​

1. Verify DNS​

# Test DNS resolution
nslookup definitions.toggly.io
nslookup api.toggly.io

# Try different DNS server
nslookup definitions.toggly.io 8.8.8.8

2. Clear DNS Cache​

# macOS
sudo dscacheutil -flushcache
sudo killall -HUP mDNSResponder

# Windows
ipconfig /flushdns

# Linux
sudo systemd-resolve --flush-caches

3. Configure DNS Server​

Update network settings to use reliable DNS:

  • Google DNS: 8.8.8.8, 8.8.4.4
  • Cloudflare DNS: 1.1.1.1, 1.0.0.1

Connection Refused​

Symptoms​

  • "ECONNREFUSED" errors
  • "Connection refused" messages
  • Can't reach Toggly servers

Solutions​

1. Check Network Connectivity​

# Test if you can reach Toggly
ping definitions.toggly.io

# Test HTTPS connection
curl -I https://definitions.toggly.io/.well-known/jwks

2. Check Firewall Rules​

Corporate networks may block certain ports:

  • Ensure port 443 (HTTPS) is open
  • Check if outbound HTTPS is allowed
  • Verify no firewall rules block toggly.io

3. Check Proxy Settings​

# Check proxy environment variables
echo $HTTP_PROXY
echo $HTTPS_PROXY

# Unset if not needed
unset HTTP_PROXY HTTPS_PROXY

Slow Network Performance​

Quick Fixes:

  1. Enable local caching
  2. Use CDN endpoints
  3. Minimize API calls
  4. Check network latency

SDK-Specific Network Configuration​

  • JavaScript - Fetch API configuration
  • .NET - HttpClient setup
  • PHP - cURL configuration
  • Go - HTTP client setup

Getting Help​

If network issues persist:

  1. Check Status Page for outages
  2. Test from different network to isolate the issue
  3. Contact support with:
    • Error messages
    • Network diagnostic results
    • Your IP address/region
    • Whether issue is consistent or intermittent