SAT
CLASS 01
Foundational Blocks
- Functional vs. Non-Functional Requirements
- Scalability
- Availability
- Reliability
- Latency
- Throughput
- Back-of-the-Envelope Estimation
- API Design
- Data Modeling
- Identifying Bottlenecks
HLD LIVE COHORT 1.0 · FOUNDING BATCH
From scrolling System Design reels to designing systems yourself.
A live, hands-on HLD (High-Level Design) cohort for software engineers who want to understand architecture, scalability, distributed systems and crack HLD interviews very easily.
225K+ developers follow DhruvTechBytes
SDE-3 / SMTS @ Oracle5+ Years Engineering1000+ DSA ProblemsProduct Company Experience
fig.01 — news-feed / fanout-on-writehealthy
Client
web · iOS · androidAPI Gateway
auth · rate-limit · L7Feed Service
GET /feedPost Service
POST /postsRedis
feed:{uid}Kafka
post.created↑ fanout-on-writeWorkers ×32
P99 LATENCY
42 ms
THROUGHPUT
12k rps
AVAILABILITY
99.99%
02 — The teacher, by the numbers
225K+
developers follow DhruvTechBytes on Instagram
- 1K+
- Medium followers
- 5+
- Years engineering
- SDE-3
- SMTS at Oracle
- 1000+
- DSA problems solved
This may be the first DhruvTechBytes cohort. It isn’t the first time Dhruv has been teaching, building systems, and sharing engineering knowledge.
03 — The gap
Watching System Design ≠ Knowing System Design
A 60-second reel gives you
@dhruvtechbytesREEL
What is Sharding?
“Split one huge table across many machines.”
0:32 / 0:60
- →The concept
- →The vocabulary
- →The intuition
A real design demands
01RequirementsFunctional vs non-functional, QPS, SLAs.
02ArchitectureComponents, boundaries, data flow.
03Trade-offsLatency vs consistency, cost vs durability.
04Scalability10× traffic without a rewrite.
05ConsistencyStrong, eventual — and when it matters.
06Failure handlingRetries, idempotency, circuit breakers.
07Distributed systems thinkingPartitions, clocks, consensus — reasoning about many machines at once.
Reels are great for the left column. The cohort exists for the right one.
04 — The reels
You’ve seen the reels.
Now let’s go deeper.
05 — From reel to real system
YOU SAW · 0:60 REEL
“What is Database Sharding?”
INSIDE THE COHORT · WEEK 04 · CLASS 07
“Design a database handling 100M+ users.”
100M users50K writes/sp99 < 50ms99.99% uptime
STEP 01 / 06 — PARTITIONING
One machine can’t hold 100M users. How do you split the data?
Horizontal vs vertical partitioning — and why range-based splits look simple until one range gets all the traffic.
users_0 … users_7 // 8 shards × ~12.5M rowsTRADE-OFFSimple queries vs independent scaling
06 — Why Dhruv
Not a résumé.
A commit history.
Every chapter shipped something — code, a decision, or a lesson. The cohort is what they add up to.
200+engineers mentored 1:1 on Topmateinit · first production code
GlobalLogic
Started as a software engineer and learned the fundamentals of building real software systems.
refactor · legacy stack → modern engineering
Nucleus Software
A challenging environment built on older technologies. Instead of waiting, Dhruv upskilled independently and moved himself toward modern engineering.
feat · architecture, from scratch
Deloitte
Built projects from scratch and took part in architectural decisions, transformations and implementations. Faced real scalability challenges — and implemented System Design trade-offs in production instead of only learning them.
CoderReviewerIndividual contributor↳ branched: content/dhruvtechbytes
release · big tech
Oracle
SDE-3 / SMTSJoined Big Tech. Today, building and reviewing systems as a Senior Member of Technical Staff.
branch · content/dhruvtechbytes
DhruvTechBytes
Started while at Deloitte — short, precise explanations of System Design, Distributed Systems, Backend Engineering and Agentic AI.
225K+engineers on Instagram
merge · engineering + teaching → HEAD
HLD Live Cohort
YOU ARE HEREThe next step: turning short-form technical education into structured, live learning.
07 — Curriculum
8 Weeks.
From first principles to designing Instagram, YouTube and Uber — live every weekend, then a bonus week.
Saturday • Sunday8 Weeks • 16 Core Classes+ 2 Bonus Classes • Mock Interviews
- Core classes
- 16
- Bonus classes
- +2
- Design problems
- 14
SUN
CLASS 02
Basic Networking Fundamentals
- Scalable System Design Components
- HTTP vs. HTTPS
- HTTP Request Structure
- HTTP Methods
- HTTP Status Codes
- Stateless HTTP
- TLS & HTTPS
- TCP vs. UDP
- Short Polling
- Long Polling
- WebSockets
- DNS Resolution
- DNS Records
- DNS vs. Load Balancer
SAT
CLASS 03
Networking & Scaling Fundamentals
- CDN
- Forward Proxy
- Reverse Proxy
- Load Balancer
- Load Balancing Algorithms
- Health Checks
- API Gateway
- Horizontal Scaling
- Vertical Scaling
SUN
CLASS 04
Database Selection
- SQL vs. NoSQL
- Relational Databases
- Predefined Schema
- ACID Properties
- NoSQL Data Models
- Key-Value
- Document
- Wide-Column
- Graph
- When to Use SQL
- When to Use NoSQL
- Database Selection Framework
SAT
CLASS 05
DB Access Patterns & Indexing
- Access Patterns
- Data Models vs. Access Patterns
- Point Lookup
- Range Query
- Equality Query
- Sorted Query
- Aggregation
- Relationship Query
- Real-World Examples
- Indexing Fundamentals
- Primary / Clustered Index
- Unique Index
- Single-Column Index
- Composite Index
- Leftmost Prefix Principle
- Non-Clustered Index
- B-Trees
- Hash Index
- Geospatial Indexes
- Inverted / Full-Text Indexes
- Index Selection Strategy
SUN
CLASS 06
DB Read/Write Patterns & High Availability
- LSM Trees vs. B-Trees
- LSM Write Path
- WAL
- MemTable
- SSTables
- LSM Read Path
- Bloom Filters
- Compaction
- Write Amplification
- Tombstones
- Read-Heavy vs. Write-Heavy Workloads
- Active-Passive
- Active-Active
SAT
CLASS 07
Replication, Sharding & Partitioning
- Database Replication
- High Availability
- Read Scalability
- Disaster Recovery
- Geographic Distribution
- Primary / Replica
- Leader / Follower
- Failover
- Synchronous Replication
- Asynchronous Replication
- Multi-Leader Replication
- Leaderless Replication
- Quorum
- Horizontal Partitioning
- Vertical Partitioning
- Sharding
- Shard Keys
- Hot Keys
- Strong Consistency
- Eventual Consistency
- Read-after-Write Consistency
- CAP Theorem
LIVE PRACTICEDesign a Distributed Database Similar to DynamoDB
SUN
CLASS 08
Caching
- Why Caching?
- Cache-Aside
- Read-Through
- Write-Through
- Write-Back
- Write-Around
- TTL
- Cache Invalidation
- Cache Stampede
- Cache Penetration
- Cache Avalanche
- Hot Keys
- Distributed Cache
- Redis
- Redis Cluster
LIVE PRACTICEDesign a Rate Limiter
SAT
CLASS 09
Messaging & Asynchronous Processing
- Synchronous vs. Asynchronous Processing
- Message Queues
- Pub/Sub
- Kafka
- Topics
- Partitions
- Consumer Groups
- Offset
- Ordering
- Delivery Semantics
- At-most-once
- At-least-once
- Exactly-once
- Retry
- Dead-Letter Queue
LIVE PRACTICEDesign a Notification System
SUN
CLASS 10
Microservices Design Patterns
- Monolith vs. Microservices
- Service Decomposition
- Database per Service
- Service Boundaries
- Service Discovery
- Synchronous Communication
- Asynchronous Communication
- Strangler Pattern
SAT
CLASS 11
CQRS + Saga + Distributed Transactions
- Distributed Transactions
- Why Traditional Transactions Don’t Work Across Services
- 2PC
- Saga
- Choreography
- Orchestration
- Compensating Transactions
- CQRS
- Event-Driven Architecture
LIVE PRACTICEDesign an E-commerce Order System
SUN
CLASS 12
Concurrency Control
- Race Conditions
- Concurrent Requests
- Database Transactions
- Isolation Levels
- Optimistic Locking
- Pessimistic Locking
- Distributed Locks
- Redis Locks
- Deadlocks
- Atomic Operations
LIVE PRACTICEDesign a Ticket Booking System
SAT
CLASS 13
Idempotency + Distributed Counters + Failure Handling
- Idempotency
- Idempotency Keys
- Duplicate Requests
- Retry-Safe APIs
- Duplicate Messages
- Distributed Counters
- Redis Counters
- Atomic Increment
- Counter Sharding
- Hot Keys
- Reliability
- Timeout
- Retry
- Exponential Backoff
- Circuit Breaker
- Bulkhead
- Graceful Degradation
- Failover
LIVE PRACTICEDesign a Payment System
SUN
CLASS 14
URL Shortener + WhatsApp + Notification + Monitoring
URL Shortener
- ID Generation
- Hashing
- Collision Handling
- ZooKeeper
- Database
- Caching
- Scaling
- Redis
- Atomic Operations
Real-World Systems
- Notification Systems
- Monitoring Systems
SAT
CLASS 15
Twitter / Instagram + YouTube
Twitter / Instagram — Read-Heavy & Write-Heavy Systems
- Fan-out
- Fan-in
- Push Model
- Pull Model
- Hybrid Model
- Celebrity Problem
- Feed Generation
- Caching
- Sharding
YouTube — Heavy Upload & Processing System
- Object Storage
- Large File Uploads
- Chunked Uploads
- Pre-Signed URLs
- Metadata
- Video Transcoding
- Async Processing
- Message Queues
- Workers
- CDN
- Video Delivery
SUN
CLASS 16
Uber + Location-Based Systems + Distributed Scheduler
Uber / Location-Based Systems
- Geospatial Indexing
- GeoHash
- QuadTree
- Location Updates
- Nearby Driver Search
- Matching
- Real-Time Updates
- WebSockets
- Distributed State
Distributed Scheduler
- Job Scheduling
- Delayed Jobs
- Workers
Final Mock Interview Session
- System Design Interview Simulation
- Requirement Clarification
- Capacity Estimation
- API Design
- Data Modeling
- High-Level Architecture
- Deep Dives
- Bottleneck Identification
- Scaling Questions
- Trade-off Discussion
- Interview Feedback
SAT
BONUS CLASSES 1 & 2
Tinder Feed + Distributed Message Queue
Both bonus designs, back to back.
DESIGN PROBLEMDesign Tinder Feed Service
- Feed Generation
- Matching / Recommendation Flow
- Read vs. Write Patterns
- Caching
- Sharding
- Scaling
- Real-Time Updates
- Handling High-Traffic Users
DEEP DIVELocation DatabasesThe best explanation you’ll get. We study Google’s S2 Geometry Library — how the Earth is cut into cells so “people near you” becomes a fast index lookup.
DESIGN PROBLEMDesign a Distributed Message Queue — Kafka
- Producers
- Topics
- Partitions
- Brokers
- Consumer Groups
- Offsets
- Replication
- Ordering
- Fault Tolerance
- High Throughput
- Scaling
SUN
OPEN SESSION
Doubts & Discussions
An open session to clear doubts and discuss anything from the eight weeks.
08 — Systems
Systems you’ll design.
Each one drawn live, component by component, then argued over — the same way these decisions get made on a real team.
14 SYSTEMS · WEEKS 04–08 + BONUS
09 — Who asks HLD
Which companies actually ask HLD?
In today’s market — almost all of them.
Once you’re past your first couple of years, a High-Level Design round is standard at product companies — from FAANG to India’s fastest-growing startups. It’s often the round that decides your level.
- SDE-1Sometimes — usually a lighter design discussion.
- SDE-2Expected — typically a dedicated HLD round.
- Senior +Central — often the round that sets your level.
FAANG & BIG TECH
- Amazon
- Meta
- Apple
- Netflix
- Microsoft
GLOBAL PRODUCT COMPANIES
- Uber
- Atlassian
- Salesforce
- Adobe
- Oracle
INDIA’S PRODUCT COMPANIES
- Flipkart
- Swiggy
- Zomato
- PhonePe
- Razorpay
- CRED
Names shown as examples of companies known to run system design rounds for engineering roles. Interview formats vary by team, level and year. Not affiliated with or endorsed by any company listed.
10 — How the cohort works
Every week follows
the same five-step loop.
- 01
Learn
Concepts from first principles, taught live.
- 02
Break Down
Deconstruct a real system into its parts.
- 03
Design
Draw your own architecture for the problem.
- 04
Discuss
Defend your trade-offs with Dhruv and peers.
- 05
Practice
Interview problems and mock interviews.
What’s included
Live sessionsSaturday & Sunday, every week.
Live Q&ABuilt into every class.
RecordingsEvery session — lifetime access.
Interview problemsReal interview-style questions.
Design practiceDesign it yourself, then review.
Mock interviewsWeekend afternoons, between weeks.
Bonus week2 extra designs + doubts & discussions.
CommunityDoubt discussions between classes.
11 — Inside a live class
What 90 minutes
actually looks like.
Sat & Sun · 5:00–6:30 PM IST · sample session
WEEK 05 · CLASS 09Messaging & Asynchronous Processing
LIVE
5:005:306:006:30
- 4:58
Join
Doors open. Say hi in chat, grab the whiteboard link.
- 5:00
Concept Breakdown
The core idea from first principles — no slides full of buzzwords.
- 5:20
Architecture Walkthrough
A real system, drawn live, component by component.
- 5:45
Real-world Trade-offs
What breaks at scale, and how engineers actually decide.
- 6:00
Interview Problem
An interview-style question, solved with the framework.
- 6:15
Live Q&A
Open floor until the questions run out.
DHRUV SINGHAL
SDE-3 / SMTS · ORACLE
12 — About
Hi, I’m Dhruv.
SDE-3 / SMTS @ Oracle
I’ve spent 5+ years building backend systems — from my first production code at GlobalLogic to architecture decisions at Deloitte and engineering at Oracle. Along the way I started explaining what I learned in 60-second reels, and 225K+ of you showed up.
This cohort is the long-form version: the reasoning, the trade-offs, and the mistakes that don’t fit in a reel.
- Interviews
- Cracked HLD rounds at Oracle, Amazon, Target and many more product-based companies
- Experience
- 5+ years
- Focus
- Backend Engineering · Distributed Systems · Agentic AI
- Teaching
- Technical education · DhruvTechBytes
13 — Writing
I write about
engineering too.
- Databases
Databases Are Just Data Structures in Disguise
Why the index you pick is the data structure you chose, whether you meant to or not.
- Caching
Shopify Killed Redis. System Design at It’s Best.
Moving inventory reservations from Redis to MySQL — how changing the granularity of contention beats scaling the infrastructure.
- Interview Prep
30 Days, 30 System Design Interview Questions
A full series working through one interview question a day, from first principles to a defensible design.
COHORT 1.0 · 2026
14 — Founding HLD cohort
Become part of DhruvTechBytes’ HLD Live Cohort 1.0.
This is the first-ever DhruvTechBytes HLD live cohort.
Founding members get first access to everything that comes next.
- Founding cohort pricing
- Direct access to Dhruv
- Live classes
- Recordings
- Community
- Mock interviews
- First access to future learning initiatives
- Starts
- 10 October 2026
- Classes
- Sat & Sun · 5:00–6:30 PM IST
- Duration
- 8 weeks + bonus week
- Price
- ₹6,999
Regular price ₹9,999
15 — Pricing
One cohort. One price.
HLD Live Cohort 1.0FOUNDING BATCH
FIRST BATCH · SAVE ₹3,00030% OFF
₹6,999Regular price ₹9,999
Founding price for the first batch only — the regular price is ₹9,999.
BATCH STARTS IN
- Starts
- 10 October 2026
- Class timings
- Sat & Sun · 5:00–6:30 PM IST
A short application form — Dhruv reads every one.
Review the curriculum firstEverything included
- Live sessions
- Live Q&A
- Recordings
- Interview problems
- Design practice
- Mock interviews
- Bonus week
- Community
16 — FAQ
Questions,
answered.
For software engineers who want to master System Design, build strong architectural thinking, and confidently tackle interviews at top product-based companies.
No. Week 01 starts from foundations.
Absolutely. The cohort is designed for engineers across experience levels — from entry-level developers and 2–4 YOE engineers to senior engineers, tech leads, architects, and beyond.
Yes. Every session is taught live by Dhruv, with time for questions built into each class.
Yes. Every session is recorded and shared with the cohort. Access never expires — recordings are yours for life.
Yes. Mock interviews run between weeks on Saturday or Sunday afternoons — the schedule is set together once the cohort starts. Week 8 also closes with a final mock interview session, with feedback.
Watch the recording and bring your questions to the next live Q&A or the community.
Both. The cohort teaches how real systems are designed; interview preparation is that same thinking, structured for 45 minutes.
8 weeks, live every Saturday and Sunday — plus a bonus week straight after. Each session runs 90 minutes.
Saturday, 10 October 2026, with Class 01 — Foundational Blocks.
HLD LIVE COHORT 1.0 · FOUNDING BATCHYou already started learning.
You already started learning.
Now learn to design.
Eight weeks, live, with the engineer whose reels you’ve been watching.