Getting queryString from GET request from website- alternative Tools then Selenium

Aim: I´m testing a specific site and I want to check wheater the sent key-value-pairs are valid.

I need to get the queryString parameters (key-value-pairs) of a GET request on a website. The queryString is only accessible via the GET requests and is NOT in the url. (I want to compare these key-value-pairs from the website later with other key-value-pairs from a file/html/..etc.)

This is what I did and know until now:

• I know I can visualize the K/V-pairs when using FireBug->Network->Parameters.

• I can get a GET request with the Selenium WebDriver, but it is complicated to extract the queryString out of the JSON-Object. [I was using Java with jsoup and json.simple]

• The only tool I know which can compare key-values on a website is Columbo.io, but I have to write the compared values manually into the tool- that is not flexible enough for my purpose.

• In my research I found the following tools: PhantomJS, Ranorex, SmartBear TestComplete, Wetator, Sahi Pro, RedGlass, TestingBot, BugBuster, Canoo Webtest. I sadly cannot find out if these tools are able to give me the key-value-pairs I desire.

Problem: With Selenium I expect to need a lot of time for writing tests, like maybe 2-4 weeks? So I am searching for other tools which can extract the key-value-pairs of a website easier or quicker.

Question: Which tools can you recommend for getting these parameters easily? And if there isn´t any better tool then Selenium then please tell me: maybe I´m overlooking some other issue and there are i.e. better API´s for parsing the JSON-Object to get the key-value-pairs or other things I could improve? Are there any sites where I can read the experiences of other persons with specific tools.

PS: This is my first question here on Stackoverflow. I hope you can understand and help me.