Client-side blocking and reporting of unauthorized network transmissions

A method for monitoring webpage traffic, the method comprising:

• receiving a domain request for a webpage to load the webpage at a client device;
• receiving, in response to the domain request for the webpage, webpage code that was injected, by a web server, with shim code;
• executing the webpage code with the injected shim code;
• receiving a domain request that was generated from other portions of the webpage that was loaded at the client device based on executing the webpage code with the shim code, wherein the domain request that was generated from the other portions of the webpage is for a different website than the webpage loaded at the client device;
• and
• processing the domain request that was generated from the other portions of the webpage based on a determination that the domain request that was generated from the other portions of the webpage satisfies one or more conditions in the shim code.

A method for monitoring webpage traffic, the method comprising:

• generating shim code;
• injecting the shim code into requested webpage code;
• transmitting the requested webpage code with the injected shim code to a requesting device;
• receiving, in response to the requesting device executing the requested webpage code with the injected shim code, runtime information, wherein the runtime information comprises a domain request that was made at the requesting device, wherein the domain request was made for a website that is different than a website loaded at the requesting device based on executing the requested webpage code with the injected shim code;
• determining whether the domain request was made at least a predetermined number of times;
• in response to determining that the domain request was made at least the predetermined number of times, adding a domain associated with the domain request to an allowlist of allowed domains;
• and
• updating the shim code with the allowlist.