Helmet helps you secure your Express apps by setting various HTTP headers. It’s not a silver bullet, but it can help!

Quick start

First, run npm install helmet --save for your app. Then, in an Express app:

var express = require('express')
var helmet = require('helmet')

var app = express()


// ...

That’s it! Helmet will set various HTTP headers to help protect your app.

How it works

Helmet is a collection of 12 smaller middleware functions that set HTTP headers. Running app.use(helmet()) will not include all of these middleware functions by default.

You can see more in the documentation.

Module Default?
contentSecurityPolicy for setting Content Security Policy  
expectCt for handling Certificate Transparency  
dnsPrefetchControl controls browser DNS prefetching
frameguard to prevent clickjacking
hidePoweredBy to remove the X-Powered-By header
hpkp for HTTP Public Key Pinning  
hsts for HTTP Strict Transport Security
ieNoOpen sets X-Download-Options for IE8+
noCache to disable client-side caching  
noSniff to keep clients from sniffing the MIME type
referrerPolicy to hide the Referer header  
xssFilter adds some small XSS protections