cr_codes

Frontend Dev | React.js & React Native | MERN | Documenting my learnings & coding journey | Open to Work 💼

[cr_codes @cr_codes]

Honestly, About Me

# Started dev journey very late.
# After college, 1 year jobless, life wasn’t going good.
# Wasted my valuable time, already too late but Still trying to make a comeback🤞
# Open for any suggestions or advice.
# Let’s connect & grow together 🙂🚀
#codinglife

[cr_codes @cr_codes]

@OpenAI @ChatGPT @ChatGPTapp

[cr_codes @cr_codes]

A feature I'd love to see in ChatGPT 👀

For long conversations, a 📌 Pin/Ribbon feature would be really useful.

Instead of scrolling through hundreds of messages to find something important again, we could simply pin it and jump back to it anytime.

@OpenAI @ChatGPT
#ChatGPT

[cr_codes @cr_codes]

A feature I'd love to see in ChatGPT 👀

For long conversations, a 📌 Pin/Ribbon feature would be really useful.

Instead of scrolling through hundreds of messages to find something important again, we could simply pin it and jump back to it anytime.

@OpenAI @ChatGPT
#ChatGPT

[cr_codes @cr_codes]

2026 started in the worst way !!

→ Joined a new company
→ Within a month, medical emergency → admitted in hospital
→ Had to resign

Thankfully recovered now.

From tomorrow:
→ Starting everything again
→ Will post my learnings while preparing to apply for jobs again

[cr_codes @cr_codes]

2026 started in the worst way !!

→ Joined a new company
→ Within a month, medical emergency → admitted in hospital
→ Had to resign

Thankfully recovered now.

From tomorrow:
→ Starting everything again
→ Will post my learnings while preparing to apply for jobs again

[cr_codes @cr_codes]

@MarZia112935496 @slotcoffee @Somayeh 👀

[cr_codes @cr_codes]

Part-1

🚀 Backend Engineering — From First Principles

Backend engineering is more than CRUD APIs.
It’s about building reliable, scalable, fault-tolerant systems.

🧠 High-level system understanding
🌐 HTTP (headers, methods, status codes, caching)
🧭 Routing & API versioning
📦 Serialization & deserialization
🔐 Authentication & authorization
✅ Validation & transformation
🧩 Middlewares
🧾 Request context
🎯 Handlers, controllers & services
🔁 CRUD deep dive
🧱 RESTful architecture
🗄️ Databases
🏗️ Business Logic Layer (BLL)
⚡ Caching strategies
📧 Transactional emails
⏳ Task queues & scheduling
🔍 Elasticsearch
❌ Error handling
⚙️ Config management
📊 Logging, monitoring & observability
🛑 Graceful shutdown
🛡️ Security
📈 Scaling & performance
🧵 Concurrency & parallelism
🗂️ Object storage & large files
⚡ Real-time backend systems
🧪 Testing & code quality
📐 12-Factor App
📄 OpenAPI standards
🔔 Webhooks
🚢 DevOps for backend engineers
🧠 Learning systems-first, not framework-first.

📌 Full in-depth breakdown → Medium (my first post) : https://t.co/Wh9BRuqxI8

#Backend #LearningInPublic

[cr_codes @cr_codes]

Part-2 of Backend from first Principles

🧠 What is a Backend? (Systems-first view)

At its core, a backend is a computer listening on open ports (80/443) for requests via HTTP, WebSockets, gRPC, etc., and serving or accepting data.

But to really understand backend engineering, you need to see the full flow, not just code 👇

🌐 Request journey
Browser → DNS → Public IP → Firewall → Reverse Proxy (Nginx) → App Server

Each layer matters:
→ DNS maps domain → IP
→ Firewalls decide which ports are reachable
→ Reverse proxies handle SSL, routing & redirection
→ App server processes the request

Same app works on:
→ localhost during development
→ Real domains in production via DNS + Nginx

📦 Why do we even need a backend?
Think of liking a post on Instagram:
→ Your app sends a request
→ Server identifies the user
→ Persists the action in a database
→ Triggers a notification to the other user
All of this happens between your click and the notification.
If you strip backend down to one word, it’s this:
👉 DATA
Fetching it, receiving it, persisting it, and acting on it.

🤔 Why not do everything on the frontend then?
Because frontend works very differently.
🖥️ Frontend reality
→ Browser first fetches the HTML
→ Then loads JavaScript, CSS, fonts, and images
→ Browser executes the JavaScript (browser = runtime)
→ All logic runs on the user’s device

🔒 Browser limitations (by design)
→ Sandboxed environment
→ No file system access
→ No environment variables
→ Strict CORS rules
→ Limited compute power
These restrictions exist because browsers execute remote code — without isolation, security would be impossible.

⚙️ Why backend logic can’t live in frontend
→ Backends need access to filesystem and secrets
→ Backends must call many external services (no CORS restrictions)
→ Heavy business logic needs stable, scalable compute
→ Clients can be low-end devices, while servers can scale CPU and RAM

✅ Final takeaway
→ Frontend = UI + interactions
→ Backend = centralized system managing data, security, state, and scale

Understanding this flow is the right starting point before learning backend principles deeply.

#Backend #LearningInPublic

[cr_codes @cr_codes]

@Naam_kafi_hai only 8 😭

[cr_codes @cr_codes]

Part-2 of Backend from first Principles

🧠 What is a Backend? (Systems-first view)

At its core, a backend is a computer listening on open ports (80/443) for requests via HTTP, WebSockets, gRPC, etc., and serving or accepting data.

But to really understand backend engineering, you need to see the full flow, not just code 👇

🌐 Request journey
Browser → DNS → Public IP → Firewall → Reverse Proxy (Nginx) → App Server

Each layer matters:
→ DNS maps domain → IP
→ Firewalls decide which ports are reachable
→ Reverse proxies handle SSL, routing & redirection
→ App server processes the request

Same app works on:
→ localhost during development
→ Real domains in production via DNS + Nginx

📦 Why do we even need a backend?
Think of liking a post on Instagram:
→ Your app sends a request
→ Server identifies the user
→ Persists the action in a database
→ Triggers a notification to the other user
All of this happens between your click and the notification.
If you strip backend down to one word, it’s this:
👉 DATA
Fetching it, receiving it, persisting it, and acting on it.

🤔 Why not do everything on the frontend then?
Because frontend works very differently.
🖥️ Frontend reality
→ Browser first fetches the HTML
→ Then loads JavaScript, CSS, fonts, and images
→ Browser executes the JavaScript (browser = runtime)
→ All logic runs on the user’s device

🔒 Browser limitations (by design)
→ Sandboxed environment
→ No file system access
→ No environment variables
→ Strict CORS rules
→ Limited compute power
These restrictions exist because browsers execute remote code — without isolation, security would be impossible.

⚙️ Why backend logic can’t live in frontend
→ Backends need access to filesystem and secrets
→ Backends must call many external services (no CORS restrictions)
→ Heavy business logic needs stable, scalable compute
→ Clients can be low-end devices, while servers can scale CPU and RAM

✅ Final takeaway
→ Frontend = UI + interactions
→ Backend = centralized system managing data, security, state, and scale

Understanding this flow is the right starting point before learning backend principles deeply.

#Backend #LearningInPublic

[cr_codes @cr_codes]

Part-1

🚀 Backend Engineering — From First Principles

Backend engineering is more than CRUD APIs.
It’s about building reliable, scalable, fault-tolerant systems.

🧠 High-level system understanding
🌐 HTTP (headers, methods, status codes, caching)
🧭 Routing & API versioning
📦 Serialization & deserialization
🔐 Authentication & authorization
✅ Validation & transformation
🧩 Middlewares
🧾 Request context
🎯 Handlers, controllers & services
🔁 CRUD deep dive
🧱 RESTful architecture
🗄️ Databases
🏗️ Business Logic Layer (BLL)
⚡ Caching strategies
📧 Transactional emails
⏳ Task queues & scheduling
🔍 Elasticsearch
❌ Error handling
⚙️ Config management
📊 Logging, monitoring & observability
🛑 Graceful shutdown
🛡️ Security
📈 Scaling & performance
🧵 Concurrency & parallelism
🗂️ Object storage & large files
⚡ Real-time backend systems
🧪 Testing & code quality
📐 12-Factor App
📄 OpenAPI standards
🔔 Webhooks
🚢 DevOps for backend engineers
🧠 Learning systems-first, not framework-first.

📌 Full in-depth breakdown → Medium (my first post) : https://t.co/Wh9BRuqxI8

#Backend #LearningInPublic

[cr_codes @cr_codes]

Coming back from a break !!

Starting a Backend from First Principles playlist by Sriniously today.

Will share my learnings along the way

Yt Link: https://t.co/AbYTXuFd9A

[cr_codes @cr_codes]

Coming back from a break !!

Starting a Backend from First Principles playlist by Sriniously today.

Will share my learnings along the way

Yt Link: https://t.co/AbYTXuFd9A

[Akshay Saini @akshaymarch7]

This year is ending in 5 days.
And I want you to pause for a second.

Not to overthink.
Not to regret.
Just to be honest with yourself.

Maybe you didn’t crack that job.
Maybe you could not be consistent.
Maybe you gave up more times than you’d like to admit.

That’s okay.

Because growth is not linear.
And real progress is invisible while it’s happening.

If you showed up even on bad days,
If you tried again after failing,
If you learnt even a little more than last year…

You’re already ahead.

Next year doesn’t need a “new you”.
It needs a more "disciplined you".

Less noise.
More focus.
Fewer excuses.
More action.

5 days left.
Don’t rush resolutions.
Just promise one thing to yourself:

You won’t quit on your goals this time.

Save this.
Read it again on Jan 1st.

Cheers,
Akshay Saini

PS. Christmas sale ends today at @namastedev_ , use coupon code "XMAS25" to get the maximum discount on all our courses.

#AllTheBest #MerryChristmas

[cr_codes @cr_codes]

@Shreyaaaa95 @akshaymarch7 Done from my side ! 🙂

[cr_codes @cr_codes]

🚀 Day 5 of #100DaysOfCode
Solved:
• 46. Permutations
• 39. Combination Sum
• 40. Combination Sum II
• 216. Combination Sum III
• 47. Permutations II

Never understood backtracking this clearly before. Thanks @akshaymarch7🙏

#namastedsa #DSA

[cr_codes @cr_codes]

🚀 Day 5 of #100DaysOfCode
Solved:
• 46. Permutations
• 39. Combination Sum
• 40. Combination Sum II
• 216. Combination Sum III
• 47. Permutations II

Never understood backtracking this clearly before. Thanks @akshaymarch7🙏

#namastedsa #DSA

[cr_codes @cr_codes]

@Sindhum__ To earn enough to buy the farm 🥸

[cr_codes @cr_codes]

@shamkyLearns Thanks!!

[cr_codes @cr_codes]

🚀 Day 4 of #100DaysOfCode

Solved (DSA):
• 78. Subsets
• 77. Combinations

• Sent 70+ DMs in linkedin for referrals.

#100DaysOfCode #DSA #LearnInPublic

[cr_codes @cr_codes]

🚀 Day 4 of #100DaysOfCode

Solved (DSA):
• 78. Subsets
• 77. Combinations

• Sent 70+ DMs in linkedin for referrals.

#100DaysOfCode #DSA #LearnInPublic