You must declare the "proxy" permission in the extension manifest to use the proxy settings API. For example: { "name": "My extension", ... "permissions": [ "proxy" ], ... } Concepts and usage Proxy settings are defined in a proxy.ProxyConfig object. Depending on Chrome's proxy settings, the settings may contain proxy.ProxyRules or a proxy.PacScript. Proxy modes A ProxyConfig object's mode attribu