The 7 building blocks behind every system

A framework for system design in the AI era

By Kay Ashaolu, UC Berkeley

Transforming junior engineers into senior architectural thinkers

AI writes code faster than ever.

But who understands what it built?

Who is this for?

Junior Engineer

"I write features but can't explain the architecture"

Vibe Coder

"I ship fast but don't know why it breaks"

Career Changer

"I can code but haven't touched production systems"

What if every system used the same pieces?

Instagram. Netflix. Uber. Slack. Stripe.

Different products. Same building blocks.

The 7 building blocks

Task blocks
Service
Service
Worker
Worker
Storage blocks
Key-Value Store
Key-Value Store
File Store
File Store
Queue
Queue
Relational DB
Relational DB
Vector DB
Vector DB
Service
Task block

Service

Receives a request. Sends a response.

Example: Every API you've ever called is a Service
Worker
Task block

Worker

Processes tasks in the background.

Example: Video encoding, email sending, report generation
Key-Value Store
Storage block

Key-Value Store

Lightning-fast lookups by key.

Example: RAM, Redis, browser cache, query cache
File Store
Storage block

File Store

Stores large binary data.

Example: S3, photos, videos, PDFs, backups
Queue
Storage block

Queue

Decouples producers from consumers.

Example: Order processing, video transcoding pipelines
Relational Database
Storage block

Relational Database

Structured data with relationships.

Example: Postgres, MySQL. Users, orders, products.
Vector Database
Storage block

Vector Database

Similarity search for AI.

Example: Recommendation engines, semantic search, RAG

How Instagram works

Service
Service
Receive upload
→
File Store
File Store
Store image
→
Relational DB
Relational DB
Save metadata
→
Key-Value Store
Key-Value Store
Cache feed
→
Worker
Worker
Notify followers

How Netflix works

Service
Service
Accept upload
→
File Store
File Store
Store raw video
→
Queue
Queue
Queue transcode
→
Worker
Worker
Process video
→
Relational DB
Relational DB
Track status

Different products.

Same 7 blocks.

Different configurations.

Once you see it, you see it everywhere.

Why this matters now

AI can write your code.

But it can't design your system.

The building blocks give you the language to direct AI.

The engineers who thrive aren't the fastest coders.

They're the ones who understand the system.

Try it yourself

3 interactive challenges below

Design Instagram. Design Netflix. Design Uber.

5 minutes each. No signup required.

Go deeper

Read the full framework: systemthinkinglab.ai/learn
7 articles. Code examples. Decision framework.
Or by email: systemthinkinglab.ai/email-course
One building block per day for seven days.

Ready for the full experience?

  • Interactive Python labs
  • Multi-part system design challenges
  • AI-powered assessment and feedback
  • Complete working code implementations

Course I: The Seven Building Blocks

systemthinkinglab.ai/course-1