01
DSA
Master problem solving, algorithms and data structures.
ArraysStringsTreesGraphsDPAdvanced DSA
One platform for the engineering skills that matter
Master Engineering.
Crack Interviews.
Learn, practice, and build the skills you need to become a better software engineer.
DSA, LLD, HLD, AI, System Design, Interview Preparation and Engineering Resources — all in one place.
Your engineering workspace Learning paths online
01
Problem Solving
DSA and algorithms
322 questions
02
Software Design
LLD and design patterns
138 problems
03
Systems at Scale
HLD and distributed systems
61+ lessons
04
AI Engineering
RAG, agents and production AI
152 lessons
05
Interview Readiness
Practice and guided preparation
Real scenarios
06
Engineering Library
Deep dives and practical guides
70+ articles
Explore Archtin
What do you want to master?
Choose a skill, understand the foundations, then move into deliberate practice.
02
LLD
Design maintainable, extensible and scalable software.
OOPSOLIDDesign PatternsLLD Problems
03
HLD / System Design
Learn how to design systems that scale from thousands to millions of users.
NetworkingDatabasesCachingQueuesDistributed Systems
04
AI Engineering
Go from AI fundamentals to building production-grade AI systems.
LLMsRAGAI AgentsMCPAI System DesignProduction AI
05
Interview Preparation
Prepare for real software engineering interviews.
DSALLDHLDBehavioralMock Interviews
06
Engineering Blogs
Deep dives into software engineering, AI, backend, cloud and more.
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Guided journeys
Choose your learning path
Follow an intentional sequence instead of guessing what to study next.
Deliberate practice
Practice like a real interview
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AI Engineering
Don't just learn AI. Build it.
Move from first principles to reliable production AI through structured lessons, visual labs, projects, and architecture practice.
- 01AI Foundations
- 02LLMs
- 03Prompt Engineering
- 04Embeddings
- 05RAG
- 06Vector Databases
- 07AI Agents
- 08MCP
- 09LangGraph
- 10AI System Design
- 11Production AI
How Archtin works
Learn → Practice → Build → Improve
A continuous loop for building engineering judgment, not just memorizing answers.
01
Learn
Understand concepts through structured learning paths.
02
Practice
Solve real DSA, LLD and HLD problems.
03
Build
Build practical AI and engineering projects.
04
Improve
Track progress and improve through feedback.
Engineering resources
Latest Engineering Insights
Practical deep dives written for engineers who want to understand how systems really work.
Search18 min read
Inverted Indexing Explained: From Documents to Millisecond Search
Search engines do not scan documents at query time. They reverse the problem: terms point to documents. Follow one sentence through analysis, postings, intersections, scoring, segments and distributed retrieval.
System Design16 min read
Distributed Locks: What They Are and How Not to Get Burned
Two workers, one cron, one payout — sent twice. A mutex cannot help you here: there is no shared memory to guard. This is what a distributed lock really buys you, and what it quietly does not.
System Design14 min read
Top 10 System Design Interview Questions (With Answers)
Ten questions cover most of what senior system design interviews actually test. Here is a crisp answer to each, the trap hidden inside it, and a deep dive link when you want the full reasoning.
System Design12 min read
Your Database Is at 100% CPU. What Do You Do?
A database at 100% CPU is rarely out of capacity. It is usually one bad plan, one missing index, or one broken cache. Here is the order to check things in — and how to say it in an interview.
System Design13 min read
What Happens When 10M Users Hit Your API?
Traffic does not break systems uniformly. It finds the one resource with the lowest ceiling — usually database connections or worker threads — and everything downstream cascades from there.
System Design13 min read
How Instagram Handles 1 Billion Likes
A like looks trivial and is one of the best scale questions there is: extreme write volume, extreme read fan-out, hot keys, and a count that must be fast but only approximately correct.
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Built for engineers who keep growing.
"Finally, an interview prep that doesn't grade me like a compiler. The AI's follow-ups felt eerily close to my Stripe loop."
Anaya R.
Senior Backend · Stripe
"I run mocks on Archtin before every onsite. The tradeoff prompts forced me to actually defend my designs."
Marcus T.
Staff Engineer · Datadog
"Cleared L5 LLD in two weeks. The Parking Lot review caught coupling I'd ignored for months."
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SDE-2 · Amazon
Pricing
One Pro plan. Pick your cadence.
Explore learning content free. Upgrade for full problem banks, projects, advanced practice, and expanded AI feedback.
Monthly
₹499/mo
Billed every month. Cancel anytime.
- Full LLD, HLD and AI practice access
- Expanded AI review credits with rubric scoring
- Mock interviews with senior-staff persona
- Submission history + attempt diffs
- Streak freeze + daily challenge bonus XP
Half-Yearly
Most popular₹349/mo
₹2,094 billed every 6 months. Save 30%.
- Full LLD, HLD and AI practice access
- Expanded AI review credits with rubric scoring
- Mock interviews with senior-staff persona
- Submission history + attempt diffs
- Streak freeze + daily challenge bonus XP
Annual
₹299/mo
₹3,588 billed yearly. Save 40%.
- Full LLD, HLD and AI practice access
- Expanded AI review credits with rubric scoring
- Mock interviews with senior-staff persona
- Submission history + attempt diffs
- Streak freeze + daily challenge bonus XP
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