Node.js proxy with undici or https-proxy-agent

Steps

1. fetch through undici’s ProxyAgent

   Import fetch and ProxyAgent from the same package and pass the agent as dispatcher. The login goes inside the URL.

   import { fetch, ProxyAgent } from 'undici';
   
   const dispatcher = new ProxyAgent('http://USERNAME:PASSWORD@HOST:PORT');
   
   const response = await fetch('https://api.ipify.org?format=json', { dispatcher });
   console.log(await response.json());

2. The https module with https-proxy-agent

   HttpsProxyAgent opens a CONNECT tunnel through the proxy for https requests. Any library that accepts a Node agent takes the same object.

   import https from 'node:https';
   import { HttpsProxyAgent } from 'https-proxy-agent';
   
   const agent = new HttpsProxyAgent('http://USERNAME:PASSWORD@HOST:PORT');
   
   https.get('https://api.ipify.org?format=json', { agent }, (res) => {
     let body = '';
     res.on('data', (chunk) => (body += chunk));
     res.on('end', () => console.log(body));
   });

3. Run it twice and compare

   Both scripts print the address api.ipify.org saw. Each run is a new process with a new connection, so two runs on residential with Randomize IP should print two addresses.

Common errors and fixes

Which line to pick

For API calls and light scraping from a Node service, datacenter IPs are the fast, cheap default. Pick residential when a site starts refusing server addresses, and ISP when your code logs in to one account from one address for weeks.

Other setup guides

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