Guides
A collection of easy to understand guides on how stuff works from encryption and encodings to networking, QR codes, and more.
How Does HTTPS Work? TLS and SSL Explained
HTTPS encrypts traffic between your browser and a server using TLS. Learn how the TLS handshake works, what certificates do, how symmetric and asymmetric encryption are combined, and what the padlock really means.
ASCII and Character Encodings Explained
Character encodings define how text is stored as bytes. Learn how ASCII works, why Unicode was created, what UTF-8 is, and why encoding mismatches cause garbled text.
How Do JWTs Work? JSON Web Tokens Explained
How the three parts of a JWT work (header, payload, signature), how HMAC signing verifies tokens without a database, and when JWTs are the wrong tool for the job.
What Is a Barcode?
How 1D and 2D barcodes work, the difference between Code 128, EAN-13, UPC, and QR codes, and when to use each type for retail, shipping, or consumer use.
What Is a UUID?
How UUIDs work, what v4 and v7 mean, why UUIDs are better than sequential integers for distributed systems, and when to use each version as a database primary key.
JSON vs XML — What Is the Difference?
A practical side-by-side comparison — syntax, verbosity, features, and when to choose JSON or XML for APIs, config files, and document formats.
What Is a Hash Function?
How MD5, SHA-1, SHA-256, and SHA-512 work, why they are one-way, what collisions are, and when each algorithm is and is not appropriate.
What Is an IP Address?
How IPv4 and IPv6 work, what public vs private means, how DHCP assigns addresses, and what an IP lookup can and cannot tell you.
What is a QR Code? How They Work and What They Store
QR codes store URLs, Wi-Fi credentials, contact details, and more. Learn how they work, what the parts mean, error correction levels, and when to use dynamic vs static codes.
URL Encoding Explained — What is %20?
URL encoding replaces characters not allowed in URLs with a % and two hex digits. Learn which characters need encoding, the difference between encodeURI and encodeURIComponent, and why + can mean a space.
What is a Regular Expression (Regex)?
A regex is a pattern that matches text. Learn what the symbols mean, how to read a real regex, and where regular expressions are used — no prior experience required.
What is Markdown? Syntax Guide with Examples
Markdown converts plain text to HTML using simple punctuation. Learn the syntax for headings, bold, lists, links, code blocks, and where Markdown is used today.
What is a Cron Expression? Syntax Explained with Examples
A cron expression is a string of five fields that defines a recurring schedule for automated tasks. Learn the syntax field by field with real examples for common schedules.
What is a Subnet Mask? CIDR and Subnetting Explained
A subnet mask divides an IP address into a network portion and a host portion. Learn how subnet masks work, what CIDR notation means, and how to calculate network ranges.
UUID v4 vs v7 — Which Should You Use?
UUID v7 embeds a Unix timestamp making it time-sortable — ideal for database primary keys. Learn when to use v4 vs v7 and why ordering matters for index performance.
How Passwords Are Hashed — bcrypt, SHA-256, and Why It Matters
Storing plaintext passwords is a critical security failure. Learn how password hashing works, why SHA-256 alone is not enough, what salting does, and why bcrypt and Argon2 are the right tools.
What is Base64? Encoding Explained with Examples
Base64 converts binary data to ASCII text for safe transport over text-only systems. Covers data URIs, JWTs, email attachments, and why Base64 is not encryption.
SHA-256 Explained — How It Works and When to Use It
SHA-256 produces a fixed 256-bit fingerprint of any input. Learn how it compares to MD5 and SHA-1, why those are broken, and when to choose SHA-256 vs SHA-512.