01Beginner
Users
API
Data
Response
Follow the request
What Is System Design?
Think in building blocks, trade-offs, and how a system behaves under real demand.
1 minStart
Learn / System Design
See how systems hold together.
Twenty-four visual, one-minute lessons for understanding architecture without getting buried in textbook prose.
24 topics2 questions eachBrowser-saved progress
Your path
0/24 topics completed
02Beginner
Web app
Catalog
Orders
Database
Many features, one deploy
Monolithic Architecture
One deployable application containing most or all product capabilities.
1 minStart
03Intermediate
Users
Identity
Catalog
Orders
Payments
Each service owns one job
Microservices Architecture
Small services own focused capabilities and can be deployed independently.
1 minStart
04Intermediate
One appSimple
Simple to start
Many servicesIndependent
Independent pieces
Monolith vs Microservices
Compare one deployable unit with independently operated services.
1 minStart
05Beginner
More usersBottleneck
Make one machine stronger
CapacityHealthy service
Add more machines
Scalability
A system's ability to handle more work without collapsing.
1 minStart
06Beginner
Scale upBigger server
Make one machine stronger
Scale outMore servers
Add more machines
Horizontal vs Vertical Scaling
Add more machines or make one machine larger.
1 minStart
07Beginner
Users
Load balancer
Server A
Server B
Traffic gets shared
Load Balancing
Distribute incoming requests across healthy servers.
1 minStart
08Beginner
LatencyHow long is one request?
ThroughputHow much work per second?
Latency vs Throughput
Understand response time versus amount of work completed.
1 minStart
09Beginner
Application
Cache
fast hitDatabase
miss, then refillCaching
Keep frequently needed data closer to the code that requests it.
1 minStart
10Beginner
User
Edge
Edge
Origin
Content takes the shorter route
CDN
Serve static and cacheable content from locations near users.
1 minStart
11Beginner
Orders
Customers
Products
Relations
Related records stay organized
SQL Databases
Store structured data in related tables with strong query capabilities.
1 minStart
12Beginner
Key
Document
Flexible shape
Fast access
Flexible shapes for fast access
NoSQL Databases
Use flexible data models for high scale or access patterns.
1 minStart
13Intermediate
RelationsFlexible
Simple to start
TransactionsDistribution
Independent pieces
SQL vs NoSQL
Choose a data model by constraints, relationships, and access patterns.
1 minStart
14Intermediate
Query
Index
Rows
Fast lookup
A shortcut to matching rows
Database Indexing
Create lookup structures that make common queries faster.
1 minStart
15Intermediate
Primary
Changes
Replica 1
Replica 2
One copy sends changes to others
Database Replication
Keep copies of database data on multiple nodes.
1 minStart
16Intermediate
Router
Shard A
Shard B
Shard C
Different records, different homes
Database Sharding
Split a large dataset across nodes using a shard key.
1 minStart
17Intermediate
CopiesAvailability
Simple to start
PartitionsCapacity
Independent pieces
Replication vs Sharding
Distinguish copies for resilience from partitions for capacity.
1 minStart
18Intermediate
Request
Healthy path
Failed node
Fallback
Keep the important path working
Fault Tolerance
Keep useful service running when components fail.
1 minStart
19Intermediate
Write
Replica A
Replica B
Read
Do both copies agree right away?
Strong vs Eventual Consistency
Choose whether reads must see the newest write immediately.
1 minStart
20Intermediate
Consistency
Availability
Partition
When the network breaks, a trade-off appears
CAP Theorem
Reason about consistency, availability, and partitions in distributed systems.
1 minStart
21Intermediate
Caller
Wait
Hand off
Worker
Work finishes later
Synchronous vs Asynchronous Communication
Compare waiting for a response with handing work off for later.
1 minStart
22Intermediate
Producer
Queue
Worker 1
Worker 2
Work waits safely
Message Queues
Buffer work between producers and consumers.
1 minStart
23Intermediate
Client
Gate
Budget
requests leftAPI
Rate Limiting
Control how much traffic a client can send in a time window.
1 minStart
24Intermediate
StatelessShared state
Any server can help
StatefulServer A
Memory stays nearby
Stateful vs Stateless Architecture
Understand where user session state lives between requests.
1 minStart