KDP categories · Top KDP authors
Functional: Amazon KDP category data
Amazon Books Best Sellers data for Functional, updated Nov 3, 2026: median price $36.99, median 29 reviews, average rating 4.4 and a KDPTop opportunity score of 22/100 (highly competitive).
| Price range (middle 50%) | $24.99 – $48.43 |
|---|---|
| Average rating | 4.4 |
| New releases (90 days) | 4% |
| Books on the list | 100 |
| Store | Books |
What stands out
- Its median reviews are 4% of the parent category Programming (735), one of the easier corners under it.
- At $36.99 its median price beats 92% of Books categories, leaving more margin per copy.
- Only 4% of its best sellers are under 90 days old, fewer than in 82% of Books categories: established titles hold the list.
Top 10 Functional best sellers
-
Python Crash Course, 3rd Edition: A Hands-On, Project-Based Introduction to Programming
by Eric Matthes
- List rank#1
- Price$26.73
- Rating4.8
- Reviews2,546
-
Learning Python: Powerful Object-Oriented Programming
by Mark Lutz
- List rank#2
- Price$53.66
- Rating4.4
- Reviews94
-
Programming Rust: Fast, Safe Systems Development
by Jim Blandy
- List rank#3
- Price$79.99
- Rating4.7
- Reviews690
-
Functional Programming in Scala, Second Edition
by Michael Pilquist
- List rank#4
- Price$59.99
- Rating4.8
- Reviews27
-
Functional Programming in Scala
by Paul Chiusano
- List rank#5
- Price$17.99
- Rating4.6
- Reviews240
-
Learning Python, 5th Edition
by Mark Lutz
- List rank#6
- Price$61.97
- Rating4.5
- Reviews1,973
-
Grokking Simplicity: Taming complex software with functional thinking
by Eric Normand
- List rank#7
- Price$49.65
- Rating4.6
- Reviews138
-
Java in a Nutshell: A Desktop Quick Reference
by Benjamin J. Evans
- List rank#8
- Price$57.89
- Reviews-
-
Command-Line Rust: A Project-Based Primer for Writing Rust CLIs
by Ken Youens-Clark
- List rank#9
- Price$38
- Rating4.5
- Reviews61
-
Programming Language Pragmatics
by Michael Scott
- List rank#10
- Price$66.75
- Rating4.9
- Reviews9
FAQ
Is Functional a good niche for Amazon KDP?
Its KDPTop opportunity score is 22/100, which makes it highly competitive. The median best seller has 29 reviews and sells for $36.99.
How many reviews do you need to rank in Functional?
The median best seller has 29 reviews, and 79% of them have fewer than 100.
What do Functional best sellers cost?
The median price is $36.99; half of the best sellers are priced between $24.99 and $48.43.
Can new books break into Functional?
4% of the current best sellers were released in the last 90 days.
About this data
Data comes from KDPTop's daily crawl of Amazon's public Best Sellers pages; medians use the latest list. The opportunity score (0–100, higher is easier to enter) combines the review barrier, the share of low-review books, list turnover, new-release share and price.