⏱ 7 min read What Is Event Sourcing? In traditional systems, the database stores the current state of an entity. When an order changes […] Read article

⏱ 8 min read Token Bucket The token bucket algorithm models a bucket of capacity B tokens that refills at rate R tokens per Read article

⏱ 8 min read Trie Node Structure Each node in a trie holds a fixed-size array of 26 child pointers (one per lowercase letter) Read article

⏱ 9 min read Compare-and-Swap (CAS) Compare-and-Swap is the atomic instruction at the heart of all lock-free algorithms. It takes three operands: a memory Read article

⏱ 8 min read Mutex Basics A mutex (mutual exclusion lock) guarantees that only one thread can hold it at any given time. The Read article

⏱ 13 min read Stack vs Heap Allocation Every running program uses two distinct memory regions for dynamic data: the stack and the heap. Read article

⏱ 13 min read Three-Way Handshake Every TCP connection begins with a three-way handshake that establishes synchronized sequence numbers on both sides and verifies Read article

⏱ 9 min read Write Path Every write in an LSM-tree storage engine lands first in two places simultaneously: the in-memory MemTable and the Read article

⏱ 8 min read Core Concept: How MVCC Works Multi-Version Concurrency Control (MVCC) solves a fundamental database problem: how to allow readers and writers Read article

⏱ 9 min read B-Tree Node Structure A B-tree of minimum degree t enforces a capacity invariant on every node except the root: each Read article

⏱ 8 min read Core Problem LFU (Least Frequently Used) is a cache eviction policy that removes the item with the lowest access frequency Read article

⏱ 8 min read Core Data Structure An LRU cache combines two data structures to achieve O(1) time for every operation. The doubly linked Read article

⏱ 9 min read Double-Entry Accounting A digital wallet is a ledger, and the correct foundation for any ledger is double-entry accounting. Every financial Read article

⏱ 9 min read Real-Time Scoring Pipeline Every transaction enters the fraud scoring pipeline synchronously before a payment decision is returned. The flow: transaction Read article

⏱ 9 min read Cart Storage Options There are three main approaches to storing a shopping cart. Client-side storage keeps the cart in the Read article