Forge Lab

The industry standard - Cloudflare, Stripe, AWS all use this

Precise rate limiting without fixed window boundary bugs

The Netflix pattern - fail fast, recover gracefully

Handle transient failures without overwhelming the service

Semaphore-based DB connection pooling

Build the ancient encryption that started it all

The unbreakable cipher (for 300 years)

Implement a cryptographic hash from scratch

Message authentication that prevents tampering

Build JSON Web Tokens from scratch - no libraries

Bcrypt, salting, and why MD5 passwords leak

Implement RSA key generation - the math of internet trust

Token bucket + circuit breaker + retry in one class

Implement the basic XOR cipher for symmetric encryption

Calculate shared secret key securely

Derive secure keys from user passwords

Bcrypt simulation - how passwords are actually stored

Escape inputs to prevent SQL Injection attacks

Verify origin matching rules

Simple slide window rate limiting per IP

Header.Payload.Signature - implement without libraries

Prevent session tampering using signed cookies

Verify anti-CSRF request tokens

HTML escape user inputs

Access control checker

bcrypt + JWT + HMAC API keys + token validation

Track causality in distributed systems

Maintain causality using Lamport Logical Clocks

Assign keys to nodes using hashing

Choose the highest ID node as coordinator

How databases survive crashes - log first, apply second

Acquire consensus lock across replicas

Coordinate atomic transaction commits

R + W > N - the math behind eventual consistency

Replicate log entries to cluster members

Sync node list statuses periodically

Coordinate word counts with Map and Reduce stages

Consistent hashing + quorum + gossip + WAL in one