Keentune
Adaptive skill practice — find your level, get sharper.

Coding Patterns practice

Design patterns and the principles behind clean code
The Gang-of-Four design patterns (factory, observer, strategy, decorator, adapter, proxy and more) by intent — and, crucially, how to tell the lookalikes apart (strategy vs state, decorator vs proxy, adapter vs facade, factory vs abstract factory). Plus SOLID, composition over inheritance, dependency injection, and the design judgment senior interviews and code reviews reward. Part of the Developer track.
• Meets you at your level — never too easy, never too hard.
• Adapts every question to how you’re doing.
• Tracks your level over time. Skill practice, not a test.
New here? Read the Coding Patterns guide
A free 16-minute primer — the mental model, the mistakes beginners make, and what to practise first.
Curriculum
221 concepts across 22 chapters, from foundations through advanced practice — each one a concept the adaptive question bank can teach and test.
A. What a pattern is, and when not to use one
8
B. Creational patterns
10
C. Structural patterns
11
D. Behavioral patterns
16
E. Choosing between the near-twins
7
F. SOLID and its real trade-offs
12
G. Coupling, cohesion and connascence
9
H. Composition, inheritance and delegation
8
I. Dependency injection and inversion of control
10
J. Domain logic patterns
8
K. Data source architectural patterns
8
L. Object-relational mapping patterns
14
M. Web presentation patterns
8
N. Distribution and session state
8
O. Offline concurrency
8
P. Base patterns
8
Q. Code smells
14
R. Refactoring: the discipline and the core moves
13
S. Refactoring conditionals, data and hierarchies
14
T. Anti-patterns
9
U. Domain-driven design and architecture-level patterns
12
V. Object-relational structural and metadata mapping
6
View the full curriculum →
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