Stop Coding. Start Architecting.

Don’t just learn system design. Learn to think like an architect.

See how systems behave under pressure. Build them. Break them. Learn to make architectural decisions you can defend in a design review.

For backend engineers moving into Senior, Staff, and Software Architect roles.

Fix the failing system Explore learning paths

131 system design lessons
·
75 runnable Docker labs
·
217 interview drills
·
68 AI engineering lessons

Written by Deepak Mishra, Senior Software Architect, 13+ years building and running production systems.

Try it now · no sign-up required

This system is failing right now. Fix it.

Two app servers, one flash sale, too much traffic. Pick an architectural fix and watch it recover. Then read what that fix cost you, because every decision in production has a trade-off.

Live simulator: 3-tier cluster

3,000 REQ/S DROPPING

Incident: Sale traffic hit 9,000 req/s. Your active app servers can only handle 6,000 req/s. Users are timing out with 502 and 504 errors. Pick a fix below.

Incoming

9,000/s

Success rate

67% (6,000/s)

Dropped load

3,000/s

Model tail (P99)

240 ms

Apply an architectural fix (click to compare trade-offs)

Incoming traffic: 9,000 requests / sec

Build your own topology in the sandbox Break real Postgres and Redis in Docker

Three pillars

Pick the engineer you want to become

Each pillar is text lessons, labs and drills on one theme. Start free in any of them. Every topic ends with what you gave up by choosing it.

131 lessons · 30 design problems · HLD and LLD

System Design & Architecture

For backend engineers who can ship features but go quiet when someone asks "why this design and not the other one?"

You will be able to

Size a system on a whiteboard with real numbers, not vibes
Choose between a cache, a queue and a read replica, and say what each one costs
Write the decision down as an ADR your tech lead can review

Trade-off: Slower than memorising twenty famous designs. But when the interviewer asks for the twenty-first, you can still answer.

Read the first lesson free See the full path

75 runnable Docker labs · Postgres, Redis, Kafka, Nginx

Production Engineering

For engineers who want to see what Postgres, Redis and Kafka actually do under load, on their own laptop.

You will be able to

Reproduce a race condition, a cache stampede and a slow query on purpose
Read the failure from logs and metrics instead of guessing
Set timeouts, retries and circuit breakers with numbers behind them

Trade-off: Labs need Docker and an hour of focus. Reading about a failure is faster. Watching it happen is what you remember in the incident call.

Run the free tatkal lab Browse all labs

68 lessons · RAG, tools, MCP, agents, evals

Enterprise AI Engineering

For backend engineers who now have to put a model call inside a real product and keep it safe, cheap and correct.

You will be able to

Build hybrid RAG where you can measure whether retrieval worked
Wire tool calling and MCP without giving the model keys to production
Set up evals, tracing and a cost budget before launch, not after

Trade-off: Every AI feature adds latency, cost per request and a new way to be wrong. This pillar is about measuring all three before you ship.

Read "Why RAG exists" free See the full path

Not sure where to start?

Coding rounds coming up too? Use the DSA lessons or play the free DSA Quest.

Look inside

What you actually work with

Here is the actual level of depth inside the lessons, the Docker lab test runners and the decision records. These are excerpts, so click through to inspect the full thing.

Decision record Cohort · Week 4

ADR-028: Transactional outbox + inbox

Problem: Publish order events to Kafka without losing messages or double-charging.
Choice: Transactional outbox on the producer, inbox on the consumer.
Trade-off: More moving parts: an outbox table, a relay loop, an inbox per consumer. Polling adds a little latency.
Breaks when: The relay is scaled to N pods without SKIP LOCKED. Then it publishes the same event twice.

Docker lab · free

Tatkal: 25 concurrent users, 1 remaining seat

PHASE 1: The Production Trap - Read, Decide In Code, Then Write
25 workers read Seat #1, think for 300 ms, then update. No lock.
Reported 'SUCCESS'   : 25
Reported 'SEAT_TAKEN': 0
Row says held_by     : user_10 (last writer wins)
>> DISASTER: 25 users were told they got Seat #1. No error was raised by the database.

Real output from the recorded run. The same script runs on your laptop and checks every result itself.

Interview drill · freeStaff / principal

Redis crashes under peak load

"100 pods, 100,000 requests per second. The primary Redis cluster dies. In 30 seconds latency goes from 15 ms to 12 seconds and pods start crashing. What do you do?"

Gets you rejected

A global cache-bypass flag. The database was sized for 5,000 RPS. It just got 100,000.

You give up

Fresh data and some features, so the database survives.

Lesson · freeFirst lesson

What system design actually is

"The architect is not the person who knows the fanciest venue. The architect is the person who makes the right call for these constraints, and can explain what they gave up."

Every lesson

Ends with a quiz, and with the trade-off you accepted by choosing that design.

Deepak Mishra

Senior Software Architect and Tech Lead

Experience: 13+ yrs
Topmate rating: 4.9★

LinkedIn YouTube Book 1:1

Why learn here

I still design, ship and debug these systems at work

I don't have a CS degree. I learned on the job, failed a fair amount, and over 13+ years moved from writing features to owning architecture. Today I lead design for enterprise platforms, mostly on .NET, C#, Azure and Angular.

So the material here starts from the failures you will meet in production: a retry storm, a connection pool that runs dry, a migration that locks a table at the wrong hour. That is why it leans on labs and failure drills more than on neat diagrams.

What I work on

Distributed systems
Microservice decomposition, event-driven design, messaging
Cloud-native on Azure
.NET and C# services, shared engineering libraries
Healthcare platforms
Clinical software built on FHIR and openEHR
AI in engineering
RAG, MCP, Semantic Kernel and Azure OpenAI in developer workflows

How I teach

Production first. We start from how the system fails, then design. Not the other way round.
Write the decision down. Every design choice becomes an ADR with what you gave up. That is what a review board asks for.
Mentor, not lecturer. I would rather ask you "why?" three times than hand you a template.

Engineer feedback

From developers making the shift

Quotes are copied as written. A longer one is cut to whole sentences, never reworded.

"Deepak’s teaching stands out. He doesn’t come across as a typical instructor but as a mentor who genuinely guides you in shifting from a developer mindset to that of a working architect. Highly recommended."

Hrishabh KaponiaFounding Cohort Member

Live CohortWeekend Batch
"This cohort is built around a questioning mindset, which develops our solution thinking approach. That is useful for the architect role and for higher roles too. This is why I highly recommend joining this cohort, to grow that mindset and adapt to the rapidly changing IT industry."
AmanFounding Cohort
1:1 MentorshipTopmate
"One of the most valuable career conversations I've had. He didn't give me a generic roadmap. He listened, understood my exact situation, and gave me a clear, practical direction I could act on immediately. The focus on fundamentals first, and knowing WHEN to use something rather than just HOW, completely shifted my thinking."
Shaad Ansari1:1 Architecture Session
YouTube Community@desiarchitect
"I'm currently transitioning into an Architect role, and this is the only YouTube channel I've found that truly focuses on that path. I discovered The Desi Architect about 3-4 weeks ago, watched all the videos, and have been eagerly waiting for new content. Finally, the wait is over!"
Mahesh SinghMoving into an Architect role

Ways to learn

Three ways in. Pick by how you learn best.

Passes and the cohort are one-time payments. Nothing renews on its own. Not ready to pay? The free lessons, free labs and the simulator above are enough to judge the quality.

Self-paced pass

Best if you learn alone, on your own clock: at night, on weekends, in the metro.

From₹499

30 days, one topic. Everything for 30 days is ₹1,299. 90-day passes also available.

Text lessons with quizzes and trade-offs
Docker labs and interview drills, by pass
Instant access, one-time payment

Compare passes

Dec Batch · Capped at 25 Seats

Live architecture cohort

Best if you have built services and want to make real design calls with a group, defend them, and get pushed on your trade-offs.

₹24,999/ 8 weekends

Live online in Hindi and Hinglish. Small batch, because the ADRs are reviewed live. Join the waitlist free first.

One running codebase, monolith to services
ADRs written in class, reviewed live
Three weeks of AI engineering on the same system

See the cohort plan

Direct 1:1 advisory

1:1 mentorship

Best if you have one specific problem: a design review, an interview loop, a move into an architect role.

Per session

Booked and paid on Topmate. Pick a slot that suits you.

Your system, your constraints, not a template
Mock design rounds with real follow-ups
Career direction from someone in the role

Book on Topmate

Passes are non-refundable once access starts. The cohort has a first-session refund. Details in the refund policy.

Start without paying a rupee

Test the material on a real problem today.

Run the free tatkal lab on your laptop. 25 users try to book one seat, and the database lets all of them win. Fix it, and you have already learned more than a diagram can teach.

Run the free lab See plans and prices