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Node.js proxying made simple. Configure proxy middleware with ease forconnect,express,next.js andmany more.

Powered by the popular Nodejitsuhttp-proxy.

This page is showing documentation for version v3.x.x (release notes)

SeeMIGRATION.md for details on how to migrate from v2.x.x to v3.x.x

If you're looking for older documentation. Go to:

• https://github.com/chimurai/http-proxy-middleware/tree/v2.0.4#readme
• https://github.com/chimurai/http-proxy-middleware/tree/v0.21.0#readme

Proxy/api requests tohttp://www.example.org

💡Tip: Set the optionchangeOrigin totrue forname-based virtual hosted sites.

// typescriptimport*asexpressfrom'express';importtype{NextFunction,Request,Response}from'express';import{createProxyMiddleware}from'http-proxy-middleware';importtype{Filter,Options,RequestHandler}from'http-proxy-middleware';constapp=express();constproxyMiddleware=createProxyMiddleware<Request,Response>({target:'http://www.example.org/api',changeOrigin:true,});app.use('/api',proxyMiddleware);app.listen(3000);// proxy and keep the same base path "/api"// http://127.0.0.1:3000/api/foo/bar -> http://www.example.org/api/foo/bar

Allhttp-proxyoptions can be used, along with some extrahttp-proxy-middlewareoptions.

• Install
• Basic usage
• Express Server Example
  • app.use(path, proxy)
• Options
  • pathFilter (string, []string, glob, []glob, function)
  • pathRewrite (object/function)
  • router (object/function)
  • plugins (Array)
  • ejectPlugins (boolean) default:false
  • logger (Object)
• http-proxy events
• http-proxy options
• WebSocket
  • External WebSocket upgrade
• Intercept and manipulate requests
• Intercept and manipulate responses
• Node.js 17+: ECONNREFUSED issue with IPv6 and localhost (#705)
• Debugging
• Working examples
• Recipes
• Compatible servers
• Tests
• Changelog
• License

npm install --save-dev http-proxy-middleware

Create and configure a proxy middleware with:createProxyMiddleware(config).

const{ createProxyMiddleware}=require('http-proxy-middleware');constapiProxy=createProxyMiddleware({target:'http://www.example.org',changeOrigin:true,});// 'apiProxy' is now ready to be used as middleware in a server.

• options.target: target host to proxy to.(protocol + host)

• options.changeOrigin: for virtual hosted sites

• see full list ofhttp-proxy-middleware configuration options

An example withexpress server.

// include dependenciesconstexpress=require('express');const{ createProxyMiddleware}=require('http-proxy-middleware');constapp=express();// create the proxy/**@type {import('http-proxy-middleware/dist/types').RequestHandler<express.Request, express.Response>} */constexampleProxy=createProxyMiddleware({target:'http://www.example.org/api',// target host with the same base pathchangeOrigin:true,// needed for virtual hosted sites});// mount `exampleProxy` in web serverapp.use('/api',exampleProxy);app.listen(3000);

If you want to use the server'sapp.usepath parameter to match requests.UsepathFilter option to further include/exclude requests which you want to proxy.

app.use(createProxyMiddleware({target:'http://www.example.org/api',changeOrigin:true,pathFilter:'/api/proxy-only-this-path',}),);

app.use documentation:

• express:http://expressjs.com/en/4x/api.html#app.use
• connect:https://github.com/senchalabs/connect#mount-middleware
• polka:https://github.com/lukeed/polka#usebase-fn

http-proxy-middleware options:

Narrow down which requests should be proxied. Thepath used for filtering is therequest.url pathname. In Express, this is thepath relative to the mount-point of the proxy.

• path matching

  • createProxyMiddleware({...}) - matches any path, all requests will be proxied whenpathFilter is not configured.
  • createProxyMiddleware({ pathFilter: '/api', ...}) - matches paths starting with/api

• multiple path matching

  • createProxyMiddleware({ pathFilter: ['/api', '/ajax', '/someotherpath'], ...})

• wildcard path matching

  For fine-grained control you can use wildcard matching. Glob pattern matching is done bymicromatch. Visitmicromatch orglob for more globbing examples.

  • createProxyMiddleware({ pathFilter: '**', ...}) matches any path, all requests will be proxied.
  • createProxyMiddleware({ pathFilter: '**/*.html', ...}) matches any path which ends with.html
  • createProxyMiddleware({ pathFilter: '/*.html', ...}) matches paths directly under path-absolute
  • createProxyMiddleware({ pathFilter: '/api/**/*.html', ...}) matches requests ending with.html in the path of/api
  • createProxyMiddleware({ pathFilter: ['/api/**', '/ajax/**'], ...}) combine multiple patterns
  • createProxyMiddleware({ pathFilter: ['/api/**', '!**/bad.json'], ...}) exclusion

  Note: In multiple path matching, you cannot use string paths and wildcard paths together.

• custom matching

  For full control you can provide a custom function to determine which requests should be proxied or not.

  /** *@return {Boolean} */constpathFilter=function(path,req){returnpath.match('^/api')&&req.method==='GET';};constapiProxy=createProxyMiddleware({target:'http://www.example.org',pathFilter:pathFilter,});

Rewrite target's url path. Object-keys will be used asRegExp to match paths.

// rewrite pathpathRewrite:{'^/old/api' :'/new/api'}// remove pathpathRewrite:{'^/remove/api' :''}// add base pathpathRewrite:{'^/' :'/basepath/'}// custom rewritingpathRewrite:function(path,req){returnpath.replace('/api','/base/api')}// custom rewriting, returning PromisepathRewrite:asyncfunction(path,req){constshould_add_something=awaithttpRequestToDecideSomething(path);if(should_add_something)path+="something";returnpath;}

Re-targetoption.target for specific requests.

// Use `host` and/or `path` to match requests. First match will be used.// The order of the configuration matters.router:{'integration.localhost:3000' :'http://127.0.0.1:8001',// host only'staging.localhost:3000'     :'http://127.0.0.1:8002',// host only'localhost:3000/api'         :'http://127.0.0.1:8003',// host + path'/rest'                      :'http://127.0.0.1:8004'// path only}// Custom router function (string target)router:function(req){return'http://127.0.0.1:8004';}// Custom router function (target object)router:function(req){return{protocol:'https:',// The : is requiredhost:'127.0.0.1',port:8004};}// Asynchronous router function which returns promiserouter:asyncfunction(req){consturl=awaitdoSomeIO();returnurl;}

constsimpleRequestLogger=(proxyServer,options)=>{proxyServer.on('proxyReq',(proxyReq,req,res)=>{console.log(`[HPM] [${req.method}]${req.url}`);// outputs: [HPM] GET /users});},constconfig={target:`http://example.org`,changeOrigin:true,plugins:[simpleRequestLogger],};

If you're not satisfied with the pre-configured plugins, you can eject them by configuringejectPlugins: true.

NOTE: register your own error handlers to prevent server from crashing.

// eject default plugins and manually add them backconst{  debugProxyErrorsPlugin,// subscribe to proxy errors to prevent server from crashing  loggerPlugin,// log proxy events to a logger (ie. console)  errorResponsePlugin,// return 5xx response on proxy error  proxyEventsPlugin,// implements the "on:" option}=require('http-proxy-middleware');createProxyMiddleware({target:`http://example.org`,changeOrigin:true,ejectPlugins:true,plugins:[debugProxyErrorsPlugin,loggerPlugin,errorResponsePlugin,proxyEventsPlugin],});

Configure a logger to output information from http-proxy-middleware: ie.console,winston,pino,bunyan,log4js, etc...

Onlyinfo,warn,error are used internally for compatibility across different loggers.

If you usewinston, make sure to enable interpolation:https://github.com/winstonjs/winston#string-interpolation

See also logger recipes (recipes/logger.md) for more details.

createProxyMiddleware({logger:console,});

Subscribe tohttp-proxy events with theon option:

createProxyMiddleware({target:'http://www.example.org',on:{proxyReq:(proxyReq,req,res)=>{/* handle proxyReq */},proxyRes:(proxyRes,req,res)=>{/* handle proxyRes */},error:(err,req,res)=>{/* handle error */},},});

• option.on.error: function, subscribe to http-proxy'serror event for custom error handling.

  functiononError(err,req,res,target){res.writeHead(500,{'Content-Type':'text/plain',});res.end('Something went wrong. And we are reporting a custom error message.');}

• option.on.proxyRes: function, subscribe to http-proxy'sproxyRes event.

  functiononProxyRes(proxyRes,req,res){proxyRes.headers['x-added']='foobar';// add new header to responsedeleteproxyRes.headers['x-removed'];// remove header from response}

• option.on.proxyReq: function, subscribe to http-proxy'sproxyReq event.

  functiononProxyReq(proxyReq,req,res){// add custom header to requestproxyReq.setHeader('x-added','foobar');// or log the req}

• option.on.proxyReqWs: function, subscribe to http-proxy'sproxyReqWs event.

  functiononProxyReqWs(proxyReq,req,socket,options,head){// add custom headerproxyReq.setHeader('X-Special-Proxy-Header','foobar');}

• option.on.open: function, subscribe to http-proxy'sopen event.

  functiononOpen(proxySocket){// listen for messages coming FROM the target hereproxySocket.on('data',hybridParseAndLogMessage);}

• option.on.close: function, subscribe to http-proxy'sclose event.

  functiononClose(res,socket,head){// view disconnected websocket connectionsconsole.log('Client disconnected');}

The following options are provided by the underlyinghttp-proxy library.

• option.target: url string to be parsed with the url module

• option.forward: url string to be parsed with the url module

• option.agent: object to be passed to http(s).request (see Node'shttps agent andhttp agent objects)

• option.ssl: object to be passed to https.createServer()

• option.ws: true/false: if you want to proxy websockets

• option.xfwd: true/false, adds x-forward headers

• option.secure: true/false, if you want to verify the SSL Certs

• option.toProxy: true/false, passes the absolute URL as thepath (useful for proxying to proxies)

• option.prependPath: true/false, Default: true - specify whether you want to prepend the target's path to the proxy path

• option.ignorePath: true/false, Default: false - specify whether you want to ignore the proxy path of the incoming request (note: you will have to append / manually if required).

• option.localAddress : Local interface string to bind for outgoing connections

• option.changeOrigin: true/false, Default: false - changes the origin of the host header to the target URL

• option.preserveHeaderKeyCase: true/false, Default: false - specify whether you want to keep letter case of response header key

• option.auth : Basic authentication i.e. 'user:password' to compute an Authorization header.

• option.hostRewrite: rewrites the location hostname on (301/302/307/308) redirects.

• option.autoRewrite: rewrites the location host/port on (301/302/307/308) redirects based on requested host/port. Default: false.

• option.protocolRewrite: rewrites the location protocol on (301/302/307/308) redirects to 'http' or 'https'. Default: null.

• option.cookieDomainRewrite: rewrites domain ofset-cookie headers. Possible values:

  • false (default): disable cookie rewriting

  • String: new domain, for examplecookieDomainRewrite: "new.domain". To remove the domain, usecookieDomainRewrite: "".

  • Object: mapping of domains to new domains, use"*" to match all domains.
    For example keep one domain unchanged, rewrite one domain and remove other domains:

    cookieDomainRewrite: {"unchanged.domain":"unchanged.domain","old.domain":"new.domain","*":""}

• option.cookiePathRewrite: rewrites path ofset-cookie headers. Possible values:

  • false (default): disable cookie rewriting

  • String: new path, for examplecookiePathRewrite: "/newPath/". To remove the path, usecookiePathRewrite: "". To set path to root usecookiePathRewrite: "/".

  • Object: mapping of paths to new paths, use"*" to match all paths.For example, to keep one path unchanged, rewrite one path and remove other paths:

    cookiePathRewrite: {"/unchanged.path/":"/unchanged.path/","/old.path/":"/new.path/","*":""}

• option.headers: object, addsrequest headers. (Example:{host:'www.example.org'})

• option.proxyTimeout: timeout (in millis) when proxy receives no response from target

• option.timeout: timeout (in millis) for incoming requests

• option.followRedirects: true/false, Default: false - specify whether you want to follow redirects

• option.selfHandleResponse true/false, if set to true, none of the webOutgoing passes are called and it's your responsibility to appropriately return the response by listening and acting on theproxyRes event

• option.buffer: stream of data to send as the request body. Maybe you have some middleware that consumes the request stream before proxying it on e.g. If you read the body of a request into a field called 'req.rawbody' you could restream this field in the buffer option:

  'use strict';conststreamify=require('stream-array');constHttpProxy=require('http-proxy');constproxy=newHttpProxy();module.exports=(req,res,next)=>{proxy.web(req,res,{target:'http://127.0.0.1:4003/',buffer:streamify(req.rawBody),},next,);};

// verbose apicreateProxyMiddleware({pathFilter:'/',target:'http://echo.websocket.org',ws:true});

In the previous WebSocket examples, http-proxy-middleware relies on a initial http request in order to listen to the httpupgrade event. If you need to proxy WebSockets without the initial http request, you can subscribe to the server's httpupgrade event manually.

constwsProxy=createProxyMiddleware({target:'ws://echo.websocket.org',changeOrigin:true});constapp=express();app.use(wsProxy);constserver=app.listen(3000);server.on('upgrade',wsProxy.upgrade);// <-- subscribe to http 'upgrade'

Intercept requests from downstream by definingonProxyReq increateProxyMiddleware.

Currently the only pre-provided request interceptor isfixRequestBody, which is used to fix proxied POST requests whenbodyParser is applied before this middleware.

Example:

const{ createProxyMiddleware, fixRequestBody}=require('http-proxy-middleware');constproxy=createProxyMiddleware({/**   * Fix bodyParser   **/on:{proxyReq:fixRequestBody,},});

Intercept responses from upstream withresponseInterceptor. (Make sure to setselfHandleResponse: true)

Responses which are compressed withbrotli,gzip anddeflate will be decompressed automatically. The response will be returned asbuffer (docs) which you can manipulate.

Withbuffer, response manipulation is not limited to text responses (html/css/js, etc...); image manipulation will be possible too. (example)

NOTE:responseInterceptor disables streaming of target's response.

Example:

const{ createProxyMiddleware, responseInterceptor}=require('http-proxy-middleware');constproxy=createProxyMiddleware({/**   * IMPORTANT: avoid res.end being called automatically   **/selfHandleResponse:true,// res.end() will be called internally by responseInterceptor()/**   * Intercept response and replace 'Hello' with 'Goodbye'   **/on:{proxyRes:responseInterceptor(async(responseBuffer,proxyRes,req,res)=>{constresponse=responseBuffer.toString('utf8');// convert buffer to stringreturnresponse.replace('Hello','Goodbye');// manipulate response and return the result}),},});

Check outinterception recipes for more examples.

Node.js 17+ no longer prefers IPv4 over IPv6 for DNS lookups.E.g. It'snot guaranteed thatlocalhost will be resolved to127.0.0.1 – it might just as well be::1 (or some other IP address).

If your target server only accepts IPv4 connections, trying to proxy tolocalhost will fail if resolved to::1 (IPv6).

Ways to solve it:

• Changetarget: "http://localhost" totarget: "http://127.0.0.1" (IPv4).
• Change the target server to (also) accept IPv6 connections.
• Add this flag when runningnode:node index.js --dns-result-order=ipv4first. (Not recommended.)

Note: There’s a thing calledHappy Eyeballs which means connecting to both IPv4 and IPv6 in parallel, which Node.js doesn’t have, but explains why for examplecurl can connect.

Configure theDEBUG environment variable enable debug logging.

Seedebug project for more options.

DEBUG=http-proxy-middleware* node server.js$ http-proxy-middleware proxy created +0ms$ http-proxy-middleware proxying request to target:'http://www.example.org' +359ms

View and play around withworking examples.

• Browser-Sync (example source)
• express (example source)
• connect (example source)
• WebSocket (example source)
• Response Manipulation (example source)

View therecipes for common use cases.

http-proxy-middleware is compatible with the following servers:

• connect
• express
• next.js
• fastify
• browser-sync
• lite-server
• polka
• grunt-contrib-connect
• grunt-browser-sync
• gulp-connect
• gulp-webserver

Sample implementations can be found in theserver recipes.

Run the test suite:

# install dependencies$ yarn# linting$ yarn lint$ yarn lint:fix# building (compile typescript to js)$ yarn build# unit tests$ yarntest# code coverage$ yarn cover# check spelling mistakes$ yarn spellcheck

• View changelog

The MIT License (MIT)

Copyright (c) 2015-2025 Steven Chim