How to fix Error: HPE_INVALID_HEADER_TOKEN: invalid header token in Node.js

# Look for error details in your logs
Error: Parse Error: Invalid header value char
    at TLSSocket.socketOnData (_http_client.js:xxx:xx)
    at TLSSocket.emit (events.js:xxx:xx)
Code: HPE_INVALID_HEADER_TOKEN

# Run your application with the legacy parser
node --http-parser=legacy index.js

# Or set it as an environment variable
export NODE_OPTIONS="--http-parser=legacy"
node index.js

const axios = require('axios');

// For a single request
const response = await axios.get('https://example.com', {
  httpAgent: new require('http').Agent({ insecureHTTPParser: true }),
  httpsAgent: new require('https').Agent({ insecureHTTPParser: true })
});

// Or set it globally
const http = require('http');
const https = require('https');

const httpAgent = new http.Agent({ insecureHTTPParser: true });
const httpsAgent = new https.Agent({ insecureHTTPParser: true });

axios.defaults.httpAgent = httpAgent;
axios.defaults.httpsAgent = httpsAgent;

const https = require('https');

const options = {
  hostname: 'example.com',
  port: 443,
  path: '/api/data',
  method: 'GET',
  insecureHTTPParser: true  // Enable lenient parsing
};

const req = https.request(options, (res) => {
  let data = '';

  res.on('data', (chunk) => {
    data += chunk;
  });

  res.on('end', () => {
    console.log(data);
  });
});

req.on('error', (error) => {
  console.error(error);
});

req.end();

# Using nvm (Node Version Manager)
nvm install 10
nvm use 10

# Verify version
node --version

Our application fails to connect from Node.js v12+ with error
HPE_INVALID_HEADER_TOKEN. This indicates your server is sending
HTTP headers with invalid characters that violate RFC 7230.
While browsers tolerate this, Node.js's strict parser rejects it.
Please review your response headers for control characters or
invalid whitespace.