How to fix Error: HTTP/2 FRAME_SIZE_ERROR (frame payload exceeds limit) in Node.js

const http2 = require('http2');

// Server advertising its settings
const server = http2.createSecureServer({
  // Maximum frame size this server will accept
  settings: {
    maxFrameSize: 16384  // Default: 16KB
  }
});

// Client setting its own maximum frame size
const client = http2.connect('https://api.example.com', {
  settings: {
    maxFrameSize: 16384
  }
});

const http2 = require('http2');
const fs = require('fs');

const options = {
  key: fs.readFileSync('private-key.pem'),
  cert: fs.readFileSync('certificate.pem'),
  settings: {
    headerTableSize: 65536,
    enablePush: true,
    initialWindowSize: 65535,
    maxFrameSize: 1048576,  // Increase to 1MB (be careful with memory!)
    maxConcurrentStreams: 100,
    maxHeaderListSize: 8192
  }
};

const server = http2.createSecureServer(options, (req, res) => {
  res.writeHead(200, { 'content-type': 'application/json' });
  res.end(JSON.stringify({ message: 'Hello from HTTP/2' }));
});

server.listen(443, () => {
  console.log('HTTP/2 server listening on https://localhost:443');
});

const http2 = require('http2');

const client = http2.connect('https://api.example.com', {
  settings: {
    maxFrameSize: 1048576  // Increase to 1MB
  }
});

const req = client.request({
  ':path': '/large-file',
  ':method': 'GET'
});

req.on('response', (headers) => {
  console.log('Status:', headers[':status']);
});

req.on('data', (chunk) => {
  console.log('Received chunk:', chunk.length, 'bytes');
});

req.on('end', () => {
  client.close();
});

req.on('error', (err) => {
  if (err.code === 'FRAME_SIZE_ERROR') {
    console.error('Frame size exceeded. Server may not support large frames.');
  }
  client.close();
});

const https = require('https');
const Agent = require('agentkeepalive').HttpsAgent;

const agentOptions = {
  maxFrameSize: 1048576
};

const options = {
  hostname: 'api.example.com',
  path: '/large-file',
  agent: new Agent(agentOptions)
};

https.get(options, (res) => {
  // Handle response
});

const http2 = require('http2');
const fs = require('fs');

const client = http2.connect('https://api.example.com');

// Stream large file in chunks rather than all at once
const fileStream = fs.createReadStream('large-file.bin', {
  highWaterMark: 16384  // Read in 16KB chunks
});

const req = client.request({
  ':method': 'POST',
  ':path': '/upload'
});

fileStream.pipe(req);

req.on('response', (headers) => {
  console.log('Upload status:', headers[':status']);
});

const http2 = require('http2');
const zlib = require('zlib');

const server = http2.createSecureServer(options, (req, res) => {
  // Compress response headers to reduce frame size
  const gzip = zlib.createGzip();

  res.writeHead(200, {
    'content-type': 'application/json',
    'content-encoding': 'gzip'
  });

  // Stream data in smaller chunks
  process.stdout.pipe(gzip).pipe(res);
});

const http2 = require('http2');

const client = http2.connect('https://api.example.com', {
  settings: {
    maxHeaderListSize: 8192  // Limit header list size
  }
});

// Check header sizes before sending
function checkHeaderSize(headers) {
  let totalSize = 0;
  for (const [key, value] of Object.entries(headers)) {
    totalSize += key.length + value.toString().length;
  }
  console.log('Header size:', totalSize, 'bytes');

  if (totalSize > 16384) {
    console.warn('Headers may exceed frame size!');
  }

  return totalSize;
}

const headers = {
  ':path': '/api/data',
  ':method': 'GET',
  'cookie': 'sessionid=...',  // Minimize cookies
  'user-agent': 'MyApp/1.0'
};

checkHeaderSize(headers);

const req = client.request(headers);

const http2 = require('http2');

const client = http2.connect('https://api.example.com');

// Listen for session errors
client.on('error', (err) => {
  console.error('Session error:', err.code, err.message);

  if (err.code === 'FRAME_SIZE_ERROR') {
    console.error('Action: Increase maxFrameSize on client or server');
  }
});

// Listen for stream errors
const req = client.request({
  ':path': '/large-file',
  ':method': 'GET'
});

req.on('error', (err) => {
  console.error('Stream error:', err.code, err.message);
});

// Get current settings
client.on('remoteSettings', (settings) => {
  console.log('Remote max frame size:', settings.maxFrameSize);
  console.log('Remote max header list size:', settings.maxHeaderListSize);
});

client.on('localSettings', (settings) => {
  console.log('Local max frame size:', settings.maxFrameSize);
});

# Test direct connection to origin server
curl --http2 https://api.example.com:8443/large-file --output test.bin

# Test through proxy
curl --http2 --proxy https://proxy.example.com:3128 https://api.example.com/large-file --output test.bin

# Compare sizes and check for errors

const http2 = require('http2');

// Some proxies may require specific settings
const client = http2.connect('https://api.example.com', {
  settings: {
    maxFrameSize: 16384,  // Use default to avoid proxy issues
    maxHeaderListSize: 8192
  },
  // Disable push if proxy has issues
  settings: { enablePush: false }
});