TRIPURA INSIDE · SOFTWARE X-RAY

What happens inside an application after you click a button?

Not a course, not an IDE. A decoder engine: pick a real feature and walk its engineering evolution — problem → rules → code → limits → ML → LLM → agent. Never starting with AI.

LOADED DECODER (JSON)
next in queue: Netflix · Recommendation · Amazon · Checkout · Google Maps · Routing · Spotify · Playlist · Instagram · Feed · WhatsApp · Chat Delivery

BUSINESS PROBLEM
A hungry user opens the app. Hundreds of restaurants are deliverable right now. Only 6 fit on the first screen. Pick the wrong 6 and the user closes the app.

Stage 01 · Zomato · Restaurant Recommendation

You open Zomato. How does it decide which restaurants to show first?

DATA IN MOTION
What we actually have
user_id
u_10293
lat, lng
12.9352, 77.6245
time
Friday 20:41
what they want
unknown
One tap. The app now knows almost nothing except who this is and roughly where they are.
LOGIC BLOCKS
1 / 3 executing
EXPLANATION
The problem before any code exists

Before engineering, there is a decision. Someone, or something, must order a list. Think about it before you scroll on.

1 · Business problem

Wrong first six = user leaves. Ranking is directly an order-conversion problem, not a cosmetic one.

2 · Engineering thinking

Reduce a large unordered set to a tiny ordered set, in under 300 ms, for every single open.

3 · Programming logic

Everything reduces to one function: rank(candidates) -> ordered list.

4 · How AI changes it

AI does not change the interface of rank(). It only changes what happens inside it.

TAKEAWAY

Hold this in your head: the function signature never changes. Only its insides evolve.

PYTHON · SYNCED TO THE ACTIVE BLOCK
No implementation yet — only the shape of the problem
python
1# Stage 1: state the problem, not the solution
2user = {'id': 'u_10293', 'lat': 12.9352, 'lng': 77.6245, 'time': '20:41'}
3 
4# supply that can physically deliver to this pin
5candidates = load_nearby(user)          # 412 restaurants
6 
7# the whole feature, in one line:
8home_screen = rank(candidates)[:6]      # <- how?
9# every stage after this replaces rank()

Run every block before moving on. The next stage stays locked until this one finishes.