How to use a proxy only for certain websites in Chrome

Sending everything through a proxy slows down sites that don’t need it and burns metered bandwidth. Usually you want only a few sites — say a regional store, an ad preview tool or a social network — to go through a proxy in a specific country, and the rest direct.

Per site, not per tab

Chrome applies one proxy configuration to the whole profile. No extension can make tab A use proxy 1 and tab B use proxy 2 for the same website. What is possible is routing by website: shop.example.de through the German proxy, example.co.jp through the Japanese one, everything else direct. If you need two completely separate sessions for the same site, use two Chrome profiles.

How it works: PAC scripts

Chrome supports Proxy Auto-Config (PAC) scripts: a small JavaScript function FindProxyForURL(url, host) that returns "PROXY host:port", "SOCKS5 host:port" or "DIRECT" for every request. You could write one by hand:

function FindProxyForURL(url, host) {
  if (dnsDomainIs(host, "example.de")) return "PROXY 203.0.113.10:8080";
  return "DIRECT";
}

— but then you need to host it, and PAC scripts can’t carry proxy passwords.

Per-site rules in ProxyNest

1. Open Manage → Per-site rules and add a rule per site: example.de → your German proxy. A plain domain covers its subdomains; *.example.de covers subdomains only; * and ? wildcards work too.
2. Choose where all other sites go: direct, or a default proxy.
3. Add sites that must never use a proxy (your bank, company tools) to Never proxy. Local network addresses go direct automatically.
4. Switch the popup to Rules. The popup shows which proxy the current site uses.

Logins work in rules mode too: each proxy’s username and password are sent when that proxy asks.