How to fix Error: HTTP 426 Upgrade Required (protocol upgrade needed) in Node.js

// WRONG - using HTTP
const http = require('http');
http.get('http://api.example.com/data', (res) => {
  console.log(res.statusCode); // 426 Upgrade Required
});

// CORRECT - using HTTPS
const https = require('https');
https.get('https://api.example.com/data', (res) => {
  console.log(res.statusCode); // 200 OK
});

// WRONG
fetch('http://api.example.com/data');

// CORRECT
fetch('https://api.example.com/data');

const https = require('https');

const options = {
  hostname: 'api.example.com',
  port: 443,
  path: '/data',
  method: 'GET',
  minVersion: 'TLSv1.2', // Require at least TLS 1.2
};

const req = https.request(options, (res) => {
  console.log(`Status: ${res.statusCode}`);
});

req.on('error', (error) => {
  if (error.code === 'ERR_SSL_VERSION') {
    console.log('Server requires TLS 1.2 or higher');
  }
});

req.end();

const https = require('https');

const agent = new https.Agent({
  minVersion: 'TLSv1.2',
  maxVersion: 'TLSv1.3',
});

fetch('https://api.example.com/data', { agent });

export NODE_OPTIONS="--tls-min-v1.2"
npm start

# Check current version
node --version

# Using nvm (recommended)
nvm install 20  # Latest LTS
nvm use 20

# Or download from nodejs.org
https://nodejs.org/

npm cache clean --force

# Use HTTPS registry (default)
npm config set registry https://registry.npmjs.org/

# Verify the registry setting
npm config get registry

# For private registries, ensure they use HTTPS
npm config set @scope:registry https://private-registry.example.com/

npm cache clean --force

# Disable strict SSL if behind corporate proxy (use with caution)
npm config set strict-ssl false

# Or set a custom CA certificate
npm config set cafile /path/to/certificate.pem

const https = require('https');
const spdy = require('spdy'); // npm install spdy

const agent = new spdy.Agent({
  protocols: ['h2', 'http/1.1'],
  rejectUnauthorized: false, // Only if testing - use with caution
});

https.get('https://api.example.com/data', { agent }, (res) => {
  console.log('Protocol:', res.httpVersion);
  res.on('data', (d) => process.stdout.write(d));
});

fetch('https://api.example.com/data', {
  headers: {
    'Upgrade': 'h2c',
    'Connection': 'Upgrade',
  }
});

const https = require('https');
const HttpProxyAgent = require('http-proxy-agent');
const HttpsProxyAgent = require('https-proxy-agent');

const httpAgent = new HttpProxyAgent('http://proxy.example.com:8080');
const httpsAgent = new HttpsProxyAgent('https://proxy.example.com:8080');

const options = {
  hostname: 'api.example.com',
  port: 443,
  httpAgent,
  httpsAgent,
  headers: {
    'Connection': 'upgrade',
    'Upgrade': 'h2c', // Request HTTP/2 over cleartext
  },
};

https.get(options, (res) => {
  console.log(res.statusCode);
});

location /api {
  proxy_pass https://backend:443;
  proxy_http_version 1.1;
  proxy_set_header Upgrade $http_upgrade;
  proxy_set_header Connection "upgrade";
  proxy_set_header Host $host;
}