Writer Rocket vs KD Spy: which is finest for you?

As an author, you need to be on Amazon if you want your career to be successful, regardless of whether you publish on Kindle Unlimited or "wide" (with multiple retailers). But the competition is no longer in the charts these days. You need to write a great story, have a fantastic cover, and have a good keyword research tool to make your book stand out – whether for Kindle keywords, competitive analysis, or Amazon ads.

Fortunately, there are a few tools you can use to reverse engineer the marketing of successful books. These tools are great for brainstorming, market research, and getting your book in the best position to sell well.

Two popular options are Publisher Rocket and KD Spy.

In this article we will compare them side by side and find out which option is the best for you.

Before we get started, I want to be completely transparent and let you know that some of the links in this article are affiliate links. This helps me keep the coffee flowing so I can keep learning and sharing with you what I'm learning. Of course, this had no impact on my rating.

Let's dive in

Publisher Rocket vs. KD Spy: Breaking It Down

Publisher Rocket and KD Spy have some important similarities. Both Publisher Rocket and KD Spy offer a similar service. They can be used by authors who want to do competitive research for their book.

However, there are some differences. For example, KD Spy is a browser extension, while Publisher Rocket is downloadable software.

To compare the two solutions when making a purchase decision, I selected the following key categories:

  1. Keyword and category research
  2. Competitive analysis
  3. Price

Note: There are certain things Publisher Rocket does that KD Spy doesn't, such as Amazon AMS keywords. I'll mention that later, but I won't include it in the main comparison function. Instead, I'm just directly comparing the elements that both tools have. A complete overview of all features of Publisher Rocket can be found here.

Before we get started, you can take a look at the features of Publisher Rocket and here the features of KD Spy.

Now we come to that.

Which one is best for keyword and category research?

One thing you should look for in every Amazon Kindle marketing tool is how they help with your keyword and category research.

When your potential readers visit Amazon, they enter search terms to find what they're looking for. Or they search for their next book in their favorite categories. You need to make sure your book appears on these searches.

Keyword and category research by Publisher Rocket

With Publisher Rocket, all you have to do is enter a starting or basic keyword for keyword research, and the software does the rest. Rocket offers keyword suggestions that show Amazon's AZ.

For example, if I type "romance", Rocket displays "romance alien", "romance anthology" and "romance book". It also shows related searches like "Romantic Fantasy Books".

Another cool feature from Rocket is that you get Amazon search data!

That means you have an estimate of how often a keyword is searched for by potential readers on Amazon each month. You will also get an estimate of how much money will be made from first class books.

Rocket also gives a score between 1 and 100 for competitive difficulties. The lower the number, the less competitive the keyword that appears on Amazon. You can quickly compare keywords and choose the best ones for your book.

In terms of categories, Rocket has access to ALL Amazon categories, including briefly read categories, and you can easily search which categories are popular and which ones give you the best results.

As you can see in the picture above, Rocket gives you information you would need a while to train on your own. For example, it shows you how many book sales you need to get to number 10 in a particular category and how high the book's Amazon bestseller ranked number 10 in that category.

You can use this information to assess which categories you can compete in.

For example, a category with a lot of competition will require a lot of sales to get to number 10 or number 1. But you also don't want to take over in a category where it's too easy to reach number 10 – so simple means that there probably aren't that many readers gobbling up these books.

All in all, Publisher Rocket's keyword and category tools are pretty powerful.

Keyword and category research by KD Spy

Category research is KD Spy's best offering, and this is where the browser extension comes in handy.

If you are in a category, you can open the extension and analyze the category. In a matter of seconds you get a comprehensive overview of the category, from the competition to the estimated profit. This feature is pretty cool and works well as an extension.

The cool thing is that KD Spy analyzes all books in the category you selected and gives you the average rank, the monthly earnings, the average selling price of the books and the average number of reviews of the books. This gives a good overview of a category you are interested in.

There is also a traffic light system that shows you how competitive the category is, how popular it is and what growth potential there is.

KD Spy also gives you the number of sales it would take to reach number 1 in the category and number 20, similar to Rocket.

While KD Spy is off guard for category research, it offers some basic keyword tools.

  • Word clouds: These collect all book titles that sell well in a particular category and give you data about which keywords are the most common. This is a handy tool because it provides niche keywords that already work for other authors.
  • Seed keywords: Similar to Rocket's Keyword Tool, you can search for a starting keyword, and Spy gives ideas for keywords. Each idea receives a traffic light color for the level of difficulty. Green lights are easiest and red lights are more difficult. You can then click on certain keyword ideas to review the data. However, the tool does not give you Google or Amazon search numbers.


I love things about these two tools. KD Spy's browser extension and usability is really cool, but Rocket's presentation of Amazon search data is a cornerstone. The fact that there are several keyword search tools in Rocket is also helpful.

For me, publisher Rocket has clear values ‚Äč‚Äčinstead of the traffic light system. This is an additional level of clarity to make informed decisions. Rocket is my winner here.

Which one is best for competitive analysis?

Okay, we've figured out which tool is best for keyword and category searches. Now let's find out which is the best one to check your competition.

To do this, you want to dig deeper than just a score of 100 or a green light.

Analysis of the KD espionage competition

KD Spy is great for competitive analysis. The tool is intuitive and offers an impressive, exportable snapshot of your competitors.

There are also several ways to find this competition. You can search for your competition using a keyword, category, or even an author page.

The author's page tool in particular is amazing. You can go directly to an author's page, use the competition tool, and view a list of available titles. As with keywords, KD Spy also creates a cloud of words that are used in the author's titles.

When you search for a category, keyword, or author, you get some cool data:

  • Competitive book prices
  • How many reviews does each book have?
  • Estimated sales
  • Check rating

This is all simple data, but you get exactly what you need.

One thing that KD Spy doesn't do is the option to display the competing book covers. This is a small setback given all of the information you provide.

Publisher Rocket competition analysis

There are several ways you can check your competition with Rocket.

First of all, you can do this through your keyword search function by clicking on "Competition". This takes you directly from the keyword function to the competition for this keyword. Pretty neat!

You can go straight to the "Competition" tab and search from there. In both cases, navigation is intuitive and Rocket is constantly updated to improve the use of the program.

One disadvantage is that you don't get the basic data that we talked about in the "Spy" section: price, rating numbers, etc. However, you can use the tool to analyze your competitors and go straight to their sites to review them.

Rocket's competitive analysis gives you the dollar amount (approximate) of sales made per day and month for each book. This is important because bestseller lists are updated regularly.

Another important feature is the age of a book. Not many people look at their contest's release dates, but they are important for several reasons:

  1. A new book can throw your analysis off the rails. A new book usually has a lot of advertising money behind it, along with a book launch campaign. Sales will drop in a few days or weeks.
  2. If all books are old and still sell well, cracking them could be a difficult niche.


For me, KD Spy's competitive analysis is slightly ahead of Rocket's. It is a great feature to be able to analyze the competition in different ways while browsing Amazon yourself.

Still, Rocket works great with its other features to analyze your competitors. It also excels in providing great dates and covers for the books you compete against.

But KD Spy is making this round.

Best for pricing and value for money

For most of my reviews, I like to leave the price category until the end. This is because I don't want to base my purchase decision only on the cost of a service. Here we look at the pricing structure of Publisher Rocket and KD Spy.

How much does KD Spy cost?

At the moment, KD Spy is priced at just $ 47. The website states that it is a "Today Only" price, but frankly it has been listed at this price for some time. I can't promise that you will still have the price of $ 47 when you visit the website, but most likely.

Spy is also a one time payment that I love. I prefer that to a subscription when it comes to software.

KD Spy also offers a 60-day money back guarantee, which is ideal. You can try KD Spy here.

Pricing options for publisher missiles

Rocket also offers a one-time payment option. For $ 97, you get lifetime access to Rocket, even if it's later a subscription model.

Rocket also has a 30-day money-back guarantee, so you can try it out with no risk. You can try Publisher Rocket here.


It really matters. KD Spy is half the price of Publisher Rocket, but Rocket gives you additional features that I can't compare directly, but Spy doesn't.

That said, if you only want the cheapest option available, regardless of features, Spy is the right choice for you.

My attitude to these two services

Drum roll please …

Both tools are excellent for research. In fact, you can benefit from using them at the same time to get the most out of keyword research and competition analysis.

Rocket offers a number of add-ons that KD Spy doesn't have (and you can read more about it in our publisher Rocket-specific review). A key feature of Rocket that KD Spy doesn't offer is the ability to search for AMS keywords that include book titles, author names, and even ASINs. This can shorten the time for advertising.

KD Spy has some cool features and I like access to the browser extension, although I think it would be better than software as an add-on to software. I find that many browser extensions can be a bit chunky, and if your browser closes, you lose all of your work. In addition, Spy's competitive analysis is great, but would benefit from a more powerful keyword research tool.

I say if you need most of the features to market your book, choose Rocket. If you want the cheapest option, choose spy.

Keep in mind that both services have a money back guarantee. So when you're on the fence, you can test both and return the one you don't want to keep.

Final thoughts

To stand out from others, you need to put your books in the best position to be successful. A keyword and competition analysis tool can pave the way to success. However, you need to choose a tool that will give you the data you need to position your books. Hopefully this article has given you enough to work with you when you make a purchase decision.

Try Publisher Rocket, KD Spy, or both, and see how you can make adjustments that increase your Amazon sales!

Brendan Hufford

Brendan Hufford