If you are preparing for system design or low-level design interviews, especially at product-based companies or FAANG , this sheet is made just for you.

We have listed all 23 essential Design Patterns (from the Gang of Four), categorized by difficulty (Easy, Medium, Hard), and crafted a system to help you track your progress, reflect with notes, and actively learn.

What makes this sheet special?

• Progress Tracker – Mark each pattern as "Done" after you’ve studied it. See your progress at a glance.
• Personal Notes – Add your own notes for revision. Write down insights, examples or things to revisit.
• Think Before You See the Solution – Each pattern comes with a hint section to help you think through the problem before jumping into the implementation. This boosts your problem-solving skills and helps you internalize the concept.
• Links – Practice problems and reference material (optional) to go deeper when needed.
• Categorized by Difficulty – Start easy, build confidence and work your way up to advanced patterns.