Neo Kim
@systemdesign.one
I Teach You System Design • 400K+ Audience
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Neo Kim
@systemdesign.one
· Jan 22
Give me 2 minutes, and I'll teach you how @bsky.app works (not joking):
Here are some probabilistic data structures you must know as a software engineer (not kidding):
They trade accuracy for space efficiency.
They're often used in:
• Databases
• Cache
• Search engines
• Network infrastructure
• Analytics
What else should make this list?
They trade accuracy for space efficiency.
They're often used in:
• Databases
• Cache
• Search engines
• Network infrastructure
• Analytics
What else should make this list?
May 8, 2025 at 1:00 PM
Here are some probabilistic data structures you must know as a software engineer (not kidding):
They trade accuracy for space efficiency.
They're often used in:
• Databases
• Cache
• Search engines
• Network infrastructure
• Analytics
What else should make this list?
They trade accuracy for space efficiency.
They're often used in:
• Databases
• Cache
• Search engines
• Network infrastructure
• Analytics
What else should make this list?
If you want to reduce latency, learn these 12 rules:
May 5, 2025 at 1:07 PM
If you want to reduce latency, learn these 12 rules:
Give me 2 mins and I'll teach you how DNS works:
May 2, 2025 at 9:45 AM
Give me 2 mins and I'll teach you how DNS works:
Meta achieves 99.99999999% cache consistency.
Here’s how they do it (in 2 minutes):
——
👋 PS - I put together a detailed case study with visuals in my newsletter:
→ newsletter.systemdesign.one/p/cache-cons...
Here’s how they do it (in 2 minutes):
——
👋 PS - I put together a detailed case study with visuals in my newsletter:
→ newsletter.systemdesign.one/p/cache-cons...
April 14, 2025 at 1:14 PM
Meta achieves 99.99999999% cache consistency.
Here’s how they do it (in 2 minutes):
——
👋 PS - I put together a detailed case study with visuals in my newsletter:
→ newsletter.systemdesign.one/p/cache-cons...
Here’s how they do it (in 2 minutes):
——
👋 PS - I put together a detailed case study with visuals in my newsletter:
→ newsletter.systemdesign.one/p/cache-cons...
Give me 2 mins and I'll teach you how Disney+ Hotstar scaled to 25M concurrent users—no fluff:
April 11, 2025 at 2:19 PM
Give me 2 mins and I'll teach you how Disney+ Hotstar scaled to 25M concurrent users—no fluff:
How I’d scale a site to 1 million users—step by step:
April 10, 2025 at 12:05 PM
How I’d scale a site to 1 million users—step by step:
HTTP status codes you must know as a web developer in 2025:
Status codes are 3-digit numbers returned by a server in response to HTTP requests.
It tells the client about the request status and indicates problems if any.
So understanding status codes will help you find site errors quickly.
Status codes are 3-digit numbers returned by a server in response to HTTP requests.
It tells the client about the request status and indicates problems if any.
So understanding status codes will help you find site errors quickly.
April 7, 2025 at 1:19 PM
HTTP status codes you must know as a web developer in 2025:
Status codes are 3-digit numbers returned by a server in response to HTTP requests.
It tells the client about the request status and indicates problems if any.
So understanding status codes will help you find site errors quickly.
Status codes are 3-digit numbers returned by a server in response to HTTP requests.
It tells the client about the request status and indicates problems if any.
So understanding status codes will help you find site errors quickly.
This lady:
• Has no tech background
• Couldn't draw well as a kid
• Knew nothing about venture capitalists
Yet she's worth $5.8 Billion - at 37.
• Has no tech background
• Couldn't draw well as a kid
• Knew nothing about venture capitalists
Yet she's worth $5.8 Billion - at 37.
April 6, 2025 at 12:28 PM
This lady:
• Has no tech background
• Couldn't draw well as a kid
• Knew nothing about venture capitalists
Yet she's worth $5.8 Billion - at 37.
• Has no tech background
• Couldn't draw well as a kid
• Knew nothing about venture capitalists
Yet she's worth $5.8 Billion - at 37.
How to write clean code.
The KYD-DTC Playbook:
The KYD-DTC Playbook:
April 2, 2025 at 1:21 PM
How to write clean code.
The KYD-DTC Playbook:
The KYD-DTC Playbook:
Give me 2 mins and I'll teach you how a database stores passwords securely (not kidding):
April 1, 2025 at 1:10 PM
Give me 2 mins and I'll teach you how a database stores passwords securely (not kidding):
Give me 2 mins and I'll teach you how Amazon S3 (actually) works:
March 29, 2025 at 1:10 PM
Give me 2 mins and I'll teach you how Amazon S3 (actually) works:
I spent hours studying how Apple Pay works, so you don't have to.
Here's what I learned distilled into 9 sentences:
Here's what I learned distilled into 9 sentences:
March 27, 2025 at 1:20 PM
I spent hours studying how Apple Pay works, so you don't have to.
Here's what I learned distilled into 9 sentences:
Here's what I learned distilled into 9 sentences:
Popular apps and open-source alternatives:
What else should make this list?
• Microsoft Office → Libre Office
• WhatsApp → Signal
• Google Chrome → Mozilla Firefox
• Adobe Photoshop → Krita
• Google → DuckDuckGo
• Windows / Mac → GNU Linux
What else should make this list?
• Microsoft Office → Libre Office
• WhatsApp → Signal
• Google Chrome → Mozilla Firefox
• Adobe Photoshop → Krita
• Google → DuckDuckGo
• Windows / Mac → GNU Linux
March 24, 2025 at 8:43 PM
Popular apps and open-source alternatives:
What else should make this list?
• Microsoft Office → Libre Office
• WhatsApp → Signal
• Google Chrome → Mozilla Firefox
• Adobe Photoshop → Krita
• Google → DuckDuckGo
• Windows / Mac → GNU Linux
What else should make this list?
• Microsoft Office → Libre Office
• WhatsApp → Signal
• Google Chrome → Mozilla Firefox
• Adobe Photoshop → Krita
• Google → DuckDuckGo
• Windows / Mac → GNU Linux
Give me 2 minutes and I'll teach you how YouTube supports 2.49 billion users with MySQL (not kidding):
March 23, 2025 at 2:33 PM
Give me 2 minutes and I'll teach you how YouTube supports 2.49 billion users with MySQL (not kidding):
I spent hours studying how Amazon S3 achieves 99.999999999% durability — because S3 is the new norm.
Here's what I learned distilled into 12 sentences (not kidding):
Here's what I learned distilled into 12 sentences (not kidding):
March 22, 2025 at 1:38 PM
I spent hours studying how Amazon S3 achieves 99.999999999% durability — because S3 is the new norm.
Here's what I learned distilled into 12 sentences (not kidding):
Here's what I learned distilled into 12 sentences (not kidding):
Git has 152 commands.
But most people don't know the powerful ones.
Here are the 4 must learn Git commands (bookmark this):
But most people don't know the powerful ones.
Here are the 4 must learn Git commands (bookmark this):
March 21, 2025 at 1:32 PM
Git has 152 commands.
But most people don't know the powerful ones.
Here are the 4 must learn Git commands (bookmark this):
But most people don't know the powerful ones.
Here are the 4 must learn Git commands (bookmark this):
Give me 2 minutes, and I'll teach you how Uber computes ETA (not kidding):
March 20, 2025 at 1:54 PM
Give me 2 minutes, and I'll teach you how Uber computes ETA (not kidding):
I spent hours studying how Amazon Lambda works — because Serverless is the new norm.
Here's what I learned distilled into 11 sentences (you'll thank me later):
Here's what I learned distilled into 11 sentences (you'll thank me later):
March 19, 2025 at 3:12 PM
I spent hours studying how Amazon Lambda works — because Serverless is the new norm.
Here's what I learned distilled into 11 sentences (you'll thank me later):
Here's what I learned distilled into 11 sentences (you'll thank me later):
If you want to become good at system design (I'm not joking), learn these case studies:
March 18, 2025 at 2:31 PM
If you want to become good at system design (I'm not joking), learn these case studies:
14 Redis use cases you must know as a software engineer (bookmark this):
What else should make the list?
What else should make the list?
March 17, 2025 at 9:18 PM
14 Redis use cases you must know as a software engineer (bookmark this):
What else should make the list?
What else should make the list?
Bad vs Good Software Engineers
What else should make this list?
What else should make this list?
March 16, 2025 at 1:19 PM
Bad vs Good Software Engineers
What else should make this list?
What else should make this list?
How the browser changes video quality automatically while streaming.
I spent hours studying about it, so you don't have to.
Here's what I learned (without the fluff):
I spent hours studying about it, so you don't have to.
Here's what I learned (without the fluff):
March 15, 2025 at 1:49 PM
How the browser changes video quality automatically while streaming.
I spent hours studying about it, so you don't have to.
Here's what I learned (without the fluff):
I spent hours studying about it, so you don't have to.
Here's what I learned (without the fluff):
Bad Debugging vs Good Debugging
What else should make this list?
What else should make this list?
March 11, 2025 at 2:45 PM
Bad Debugging vs Good Debugging
What else should make this list?
What else should make this list?
Give me 2 minutes, and I'll teach you
how CloudFlare serves 20% of internet traffic with only 15 Postgres clusters:
how CloudFlare serves 20% of internet traffic with only 15 Postgres clusters:
March 7, 2025 at 1:11 PM
Give me 2 minutes, and I'll teach you
how CloudFlare serves 20% of internet traffic with only 15 Postgres clusters:
how CloudFlare serves 20% of internet traffic with only 15 Postgres clusters: