The library
Every poster is a real frame from a real video. Pick one and press play.
Why do I get a CORS error?
Why the browser blocks your fetch request, and the one header that fixes it. Animated, step by step.
How does DNS work?
How example.com becomes 93.184.216.34, resolvers, root servers, and caching, animated, step by step.
What is a reverse proxy?
The server that stands in front of your servers, security, caching, and load balancing in one place.
JWT auth, explained
Login once, carry a signed token, get verified everywhere, JSON Web Tokens animated, step by step.
What does a load balancer do?
Why one server isn't enough, and how traffic gets spread across many, animated, step by step.
WebSockets: staying connected
From one HTTP upgrade to a two-way live connection, how chat and realtime apps stay connected.
Inside the TLS handshake
What actually happens in the padlock moment, keys, certificates, and the handshake animated.
Bubble sort, step by step
Compare neighbors, swap, repeat, watch an array sort itself step by step, with the O(n²) catch.
Reversing a linked list
The classic interview question, animated: flip one arrow at a time with prev and curr pointers.
Finding a value in a BST
Why finding a value in a BST takes 4 steps instead of 15, halving the tree at every comparison.
Binary search, explained
Find anything in a sorted array by halving the search space, lo, hi and mid pointers animated.
What is a stack?
Push, pop, and why the last thing in is the first thing out, the data structure behind undo and call stacks.
Inserting into a BST
Walk down like a search, attach like a leaf, keeping the BST ordering promise intact.
What is a vector database?
Documents become points in space, and search becomes finding the nearest neighbors. The idea behind AI search, animated.
Reverse a stack with an array
Pop everything once and the order flips. Watch each value fly from the stack into the array.
The TCP 3-way handshake
SYN, SYN-ACK, ACK: how two machines agree to talk before a single byte of data moves.
How does a hash map work?
Why lookups are instant: a hash function turns any key straight into a bucket index.
The JavaScript event loop
One thread, never blocked: the call stack, the task queue, and the loop between them.
Why a CDN makes sites fast
Why sites feel fast everywhere: copies of your content live close to every user.
Recursion and the call stack
A function calling itself is just the call stack doing its job. Watch the frames pile up and unwind.
What happens in a git merge?
Two branches, one history: how git finds the common ancestor and weaves the work together.
How do rockets reach orbit?
It's not about going up. It's about going sideways fast enough to keep missing the ground.