Hospital ER
Three patients walk in. A heart attack, a sprained ankle, a fever. Which do you treat first?
Decoded ·Priority Queue
Coming late 2026
Decodory
Decode the tech behind everyday life.
Solve real-world puzzles — a tea stall during evening rush, a hospital ER, a busy bank — and discover the IT concepts hidden inside them. No code. No jargon. Just decode.
Busy Bank
Two ATMs. One account. Both customers withdraw at the same second. Who gets the money?
Decoded ·Race Condition
Tea Stall · 6 PM
Puzzle 00160 customers / hour. Aunty is the only one taking orders, making chai, and handing them out. Customers wait 8 minutes. Yesterday, 38 walked away.
What would you do?6 options
Hidden concept ·Queue Theory + Load Balancing
How it works
Every app you build, you've already built without code.
Read a real story
A delivery hub during Diwali rush. A library with a missing book. A bank with two ATMs and one account. Everyday situations — with a hidden engineering problem inside.
Solve it your way
Pick the right mix of options. Drag steps in order. Balance the constraints. Use common sense, not jargon.
Discover what you built
Turns out you just designed a load balancer. Or prevented a race condition. Or chose the right database for the job. Now you know the name.
What you'll learn
Six pillars. One puzzle a day across all of them.
Programming Logic
Deadlocks, recursion, race conditions — and the bugs they cause.
Networking
DNS, load balancing, packet loss — the invisible plumbing of the web.
Security
Phishing, encryption, SQL injection — why attackers think the way they do.
Database
Indexing, caching, ACID — the choices that make a system fast or fatal.
DevOps
CI/CD, rollback, scaling — how production stays alive at 3 AM.
System Design
Queues, pub-sub, microservices — building things that don't fall over.
Why Decodory
Real-world stories. Hidden tech.
It's a puzzle, not a quiz
We don't ask “which of these is load balancing?” We hand you a tea stall during rush hour and a ₹5,000 budget. You figure it out. Then we reveal the concept.
Built for working engineers
Easy isn't easy. Medium isn't medium. We calibrated difficulty against a 10-year Google engineer, not a CS freshman. Every wrong answer is a real IT concept — close, but not quite right.
One concept a day
A new daily puzzle every morning. Solve it on your commute, share your result, build a streak. Then come back tomorrow.
Today's preview
A real puzzle — try it before launch.
Puzzle · 001 · the tea stall problem
It's 6 PM at Trichy Junction. Aunty's tea stall sees 60 customers an hourduring evening rush, but she's the only one taking orders, making chai, and handing them out. Customers wait 8 minutes for a ₹15 cup. Yesterday 38 of them walked away. She has ₹5,000 saved upto fix the problem before next Monday's rush.
What would you do?
- AHire 2 helpers₹4,000
- BAdd a mobile pre-order lane₹1,500
- CExpress counter (chai only)₹1,200
- DSelf-service kiosk₹800
- EBuy a bigger counter₹2,500
- FRaise prices to reduce demand₹0
There are right answers. There are tempting wrong ones. And there's a concept hiding in the right combination. Get notified when we launch to find out which one.
Get on the waitlist
First puzzle drops late 2026.
Tick Decodory on the form. We'll email you on launch day with a direct link to Puzzle 001. Then one fresh puzzle every morning, right on time for your commute.
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