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⚑ System Design + DSA β€” two tracks, one platform
System design & DSA.
Actually understand it.

Two structured tracks: learn system design with diagrams, MCQs, and challenges β€” or master DSA patterns with in-browser coding and real test cases.

β–Ά Start learning free⌨ Practice DSA⬑ Browse SD challenges
βœ“ No card required⚑ Early access
Overview
Learn
Practice tests
SD challenges
Concepts
πŸ—„ CachingFree
βš– Load bal.Free
πŸ“š DatabasesPro
πŸ“¨ Msg queuesPro
SD challenges
πŸ”— URL shortener
🐦 Design Twitter
πŸ—„ CachingFree

Caching stores frequently accessed data in fast storage so future requests skip the slow source β€” cutting latency and reducing DB load at scale.

Cache-aside read flow
ClientrequestCacheRedisHIT βœ“MISSDatabasesource of truthpopulate cacheEvictionTTL / LRU
πŸ“ Notes β€” Caching
Today, 10:42 am
Write-around avoids polluting cache with cold data.
Yesterday
Cache stampede β†’ mutex lock or PER.
Add a note...
Save note
94
SD concepts
SD
51
SD challenges
SD
3
Difficulty levels
SD
17
DSA patterns
DSA
12
Practice problems
DSA
4
Coding languages
DSA
Two tracks
System Design and DSA β€” in one place

Most engineers need both. TechCookies covers them together so you don't have to juggle five different resources.

⬑
System Design
94 concepts Β· 51 challenges

Learn caching, databases, load balancers, queues, and more through structured concept pages with inline architecture diagrams. Then apply everything in real end-to-end system design challenges.

βœ“Inline architecture diagrams
βœ“MCQ practice tests per concept
βœ“End-to-end design challenges (Twitter, YouTube, …)
βœ“AI-powered evaluation & rubric scoring
Browse SD concepts β†’
⌨
DSA & Coding
17 patterns Β· 12 problems

Master algorithmic patterns (two-pointer, sliding window, BFS, dynamic programming…) with guided concept sections, then practice in-browser with real test cases β€” no setup needed.

βœ“In-browser TypeScript execution
βœ“Pattern-first concept sections
βœ“Guided + expert practice modes
βœ“Real test cases with pass/fail feedback
Browse DSA patterns β†’
Everything you need
Learn, code, design β€” in one flow

Not just content. A structured path from understanding a concept to using it β€” whether that's solving a coding problem or designing a real system.

πŸ—„
Concept learning with diagrams
Each SD concept has clear explanations and inline architecture diagrams β€” not walls of text.
βœ…
Topic practice tests
MCQs per concept with explanations. Verify you've really understood before moving on.
πŸ—Ί
End-to-end SD challenges
Design Twitter, YouTube, URL shorteners. Each challenge shows which concepts it tests.
⌨
In-browser code execution
Write TypeScript and run it against real test cases instantly β€” no server, no setup, no waiting.
β‡Œ
Pattern-first learning
Learn the underlying pattern (two-pointer, sliding window, BFS…) before tackling problems. Concepts stick.
🎯
Guided & expert modes
Start guided with hints and step-by-step support. Switch to expert mode once you're confident.
πŸ“
Notes, highlights & flashcards
Add notes as you read. Flip flashcards to drill concepts. Works across both SD and DSA tracks.
⟳
Concept β†’ challenge bridge
After each concept, a direct link to the challenge or problem that uses it β€” cementing understanding.
πŸ“Š
Progress tracking
See what you've completed, practice scores, and which concepts need more work across both tracks.
Curriculum
System Design β€” 94 concepts, 51 challenges

Two free concepts to start. Upgrade to unlock the full curriculum.

πŸ—„
Caching
Cache strategies, Redis, CDNs, eviction policies, stampede prevention.
βš–
Load balancing
L4 vs L7, round-robin, least connections, health checks, sticky sessions.
πŸ’Ύ
Databases & storage
SQL vs NoSQL, sharding, replication, indexing, ACID.
πŸ”’ Pro
πŸ“¨
Message queues
Kafka, pub/sub, fan-out, dead-letter queues, backpressure.
πŸ”’ Pro
⬑
Consistent hashing
Distribute data across nodes with minimal reshuffling on changes.
πŸ”’ Pro
πŸ”’
+ 89 more concepts
Rate limiting, auth, real-time, streaming, payments, frontend architecture, and more.
πŸ”’ Pro
DSA Curriculum
17 algorithmic patterns

6 free patterns to start, covering the foundational techniques every interview tests.

β‡Œ
Two-Pointer FamilyFree
Ξ© Big O & Complexityβ–€ Arraysβ‡Œ Two-pointerβ§– Sliding window↩ Recursion & call stack# Hash maps
⬑
Trees & GraphsπŸ”’ Pro
β†’ Linked lists⊟ Stacks & queuesβŠ• Binary search⬑ Trees β€” BFS & DFSβ¬’ Graphs β€” BFS & DFS
β—ˆ
OptimisationπŸ”’ Pro
β–¦ Dynamic programmingβ©“ Heaps & priority queues⊳ Tries⊌ Union-FindβŠ› Dijkstra's algorithm↑ Topological sort
Explore DSA track β†’
Pricing
Start free. Upgrade when ready.

No credit card required. Both tracks included on every plan.

Free
β‚Ή0forever
βœ“30 SD concepts and practice tests
βœ“20 free SD challenges
βœ“6 free DSA patterns + practice problems
βœ“Notes & flashcards on both tracks
βœ“Advanced SD patterns & expert tips
βœ“Full DSA curriculum (17 patterns)
Get started free
Pro
β‚Ή499/ month
βœ“All 94 SD concepts + advanced patterns
βœ“Full SD prompt library β€” 51 challenges across 3 tracks
βœ“All 3 difficulty levels: beginner β†’ senior
βœ“All 17 DSA patterns β€” trees, graphs, DP, heaps & more
βœ“12+ DSA problems with full solutions
βœ“Java, Python & Go on DSA problems (TypeScript always free)
βœ“Diagram canvas with save & restore
βœ“AI-powered SD evaluation + rubric scoring
βœ“Expert solutions for every prompt
βœ“Notes, highlights & flashcards
βœ“Progress tracking & weak area detection
βœ“Next prompt & problem recommendations
Upgrade to Pro β†’
FAQ
Common questions

Yes. Caching and load balancing are among the most commonly tested system design concepts. You also get the URL shortener SD challenge, practice tests, and full notes/flashcard functionality.

Ready to get started?

94 SD concepts Β· 51 challenges Β· 17 DSA patterns Β· 12 practice problems. Free to start.

β–Ά Start learning free⌨ Practice DSAView pricing