TDR

The Design Round

Crack the design round. Every time.

Curated problem sheets and core concept deep dives for system design and machine coding interviews. Track progress, build intuition, ship confidence.

Start with Arch 25Machine Coding

System Design

HLD Sheets

Progress from foundation to full coverage.

Arch 25

25

Crash sheet for broad HLD readiness: the highest-frequency systems and reusable patterns to cover first.

Arch 50

50

Serious SDE2/Senior prep: Arch25 plus deeper infra, data, reliability, and advanced product systems.

Arch 75

75

Overprepared track: Arch50 plus high-signal variants, niche domains, and company-style specialization.

Arch All

103

Complete HLD question bank for full coverage, and long-term mastery.

+ Core Concepts (33 deep dives) →

Machine Coding

LLD Sheets

OOP design, LLD patterns, and interview implementation.

MaCo 30

30

Core 30 machine-coding problems — highest ROI for interviews.

MaCo 60

60

MaCo 30 plus extended coverage across all categories.

MaCo All

103

Complete list of all 103 machine-coding problems.

+ Design Patterns (31 patterns) →

Progressive difficulty

Start with the highest-ROI 25 problems. Expand when you’re ready.

Track what you’ve studied

Progress is saved locally — checkmarks, stars, and notes persist in your browser.

Both rounds covered

System design HLD and machine coding LLD — one place, structured prep.