Developer Guides
70 in-depth tutorials. Each one covers a specific topic — no filler, no fluff.
Step-by-Step Tutorials
How to Generate a UUID
Generate UUID v4 online, via CLI, or in code — in under a minute.
How to Format & Validate JSON
Format messy JSON in three steps and decode any parse error.
How to Encode & Decode Base64
Decode Base64 strings, handle the URL-safe variant, fix errors.
How to Test a Regular Expression
Test patterns against real text and catch false positives early.
How to Generate a Strong Password
Length beats complexity — generate 80+ bits of entropy in four steps.
How to Convert a Unix Timestamp
Epoch to date and back — seconds vs milliseconds, UTC vs local.
How to Decode a JWT Token
Inspect header, payload, and expiry to debug 401 errors fast.
How to Generate MD5 & SHA-256 Hashes
Hash text, verify file checksums, pick the right algorithm.
How to Pick & Convert CSS Colors
HEX, RGB, HSL conversion, hover shades, and WCAG contrast checks.
How to Preview Markdown Online
Render Markdown live and catch silent formatting failures.
Data & APIs
JSON Data Debugging Guide
Find, fix, and prevent common JSON errors in API development.
JSON Explained: Syntax, Types, Parsing & Pitfalls
The six value types, how a parser reads JSON, escaping, number traps, and the JSON bomb.
CSV to JSON Conversion
Convert data between CSV and JSON, handle edge cases and delimiters.
Number Bases: Binary, Hex & Octal
Understand and convert between decimal, hex, binary, and octal.
Unix Timestamps & Timezone Handling
Epoch time, seconds vs milliseconds, and timezone best practices.
Timezone Conversion: UTC, DST & Best Practices
Store in UTC, display in local time, handle DST transitions correctly.
Cron Expressions Guide
Schedule automated tasks with the five-field cron syntax.
Encoding & Web
Web Encoding: Base64, URL & HTML Entities
The three encoding schemes every developer encounters.
URL Encoding Explained: How Percent-Encoding Works
Why %20 and %C3%A9 appear, how spaces become +, and UTF-8 bytes.
HTML Entities Explained: &, <, and the Rest
Named, decimal, and hex entities, the ampersand trap, and non-breaking spaces.
Base64 Explained: Encoding, Padding & Why It Is Not Encryption
How 3 bytes become 4 characters, the = padding rule, and URL-safe Base64.
URL Structure Demystified
Protocol, host, path, query — every component explained.
URL Slugs: SEO-Friendly Naming
Create clean, readable URL slugs that improve click-through rates.
String Escaping in JS & JSON
Escape sequences for quotes, backslashes, and control characters.
Text & Content
Text Processing for Developers
Regex patterns, case conversion, deduplication — practical workflows.
Naming Conventions Across Languages
camelCase, snake_case, kebab-case, PascalCase, and when to use each.
Character Counting & Platform Limits
Twitter, SMS, SEO meta tags — every platform limit explained.
Word Counts & SEO
Content length benchmarks for titles, meta descriptions, and blog posts.
Line Counting for Code & Data
Total lines, non-empty lines, empty lines — what each metric reveals.
Line Deduplication Guide
Clean up lists and data files by removing duplicate lines.
Removing Empty Lines from Text
Strip blank lines from PDF exports, email threads, and legacy data.
Sorting Lines: Alphabetical & Numeric
Order lists for scanning, comparing, and import validation.
Shuffling Lines for Randomization
Fair test questions, unbiased surveys, and random group assignment.
Reversing Text in Three Modes
Character, line, and word order reversal — when each is useful.
Lorem Ipsum in Design & Development
When to use placeholder text, and when to replace it with real content.
Random String Generation
Test data, development tokens, and placeholder content explained.
Robots.txt: Rules, Syntax & Validation
Control search engine crawlers — correct syntax and common mistakes.
XML Sitemaps: Structure, Limits & SEO Best Practices
Required fields, size limits, sitemap indexes, and submission workflow.
Dev Tools: JSON Schema, LLMs & Mock Data
JSON Schema generation, typed code from JSON, LLM token counting, prompt formatting.
Shell Tools: Permissions & Escaping
Unix chmod permissions, shell string escaping for safe bash commands.
Crypto Tools: Hashing, HMAC & Encryption
MD5, SHA, bcrypt, AES, RSA, HMAC — when to use each cryptographic primitive.
AES Encryption Explained: How It Works & Best Practices
Rijndael internals, block cipher modes, IV reuse, padding oracles, PBKDF2, AEAD.
Color Tools: Convert, Generate & Check Accessibility
HEX, RGB, HSL, CMYK conversion, WCAG contrast, Tailwind palettes.
Image Tools: Compress, Resize & Convert
Optimize images for the web — compression, resizing, format conversion and favicon generation.
HTML Minification: Why, How & When
Strip whitespace, comments, optional tags. Works with compression.
CSS Minification: Compressing Stylesheets
Remove comments, whitespace, trailing values from production CSS.
Network & Security
DNS Records Explained
A, AAAA, MX, CNAME, TXT, NS — every record type with examples.
DNS Log Monitoring for Security & Propagation
Real-time DNS query logging for XXE, SSRF detection and DNS propagation tracking.
IP Addresses & Geolocation
IPv4 vs IPv6, public vs private, and how IP geolocation works.
HTTP Headers: Security, Caching & Performance
CSP, HSTS, Cache-Control, ETag — headers that protect and accelerate your site.
WHOIS Lookup: Domain Research & Ownership
Domain registration dates, registrars, name servers, and post-GDPR privacy.
Ping & Network Latency: Diagnosing Connectivity
RTT, jitter, packet loss — what ping metrics mean and how to use them.
Port Checking & TCP Ports: Network Security Audit
Which ports should be open, which should never face the internet.
User Agent Parsing
Decode browser, OS, and device from any user agent string.
SSL Certificates Explained
Certificate chains, expiry, verification, and self-signed certs.
Password Security & Hash Algorithms
MD5 vs SHA-256, bcrypt, Argon2, and password best practices.
Query String Parsing: Debugging URL Parameters
Encoding edge cases, OAuth debugging, UTM parameters, and SEO considerations.
Code Quality
SQL Tools: Format, Validate & Minify
Consistent formatting, syntax validation, and query minification for production.
SQL Formatting Guide
Write clean, readable queries with consistent formatting conventions.
Text Diffing for Code Review
Read diff output, compare configs, and debug with line-by-line comparison.
Regex Cheat Sheet & Reference
Character classes, quantifiers, lookarounds — every construct with examples.
Regex Generator: Pre-built Validation Patterns
Email, URL, phone, IP, date patterns — copy-ready for JS, Python, PHP.
Cron Expressions: Syntax, Fields & Scheduling
Build cron schedules visually. Covers GitHub Actions, K8s, and crontab.
CSS Colors & Gradients Guide
HEX, RGB, HSL explained. Build palettes and gradients.
QR Codes: How They Work
Error correction, sizing, encoding, and practical uses beyond URLs.
CSS Flexbox: Layout, Alignment & Spacing
Flex-direction, justify-content, align-items — every property explained.
CSS Grid: Two-Dimensional Layout
Grid-template, fr units, template areas, explicit placement.
CSS Box Shadow: Design, Layering & Performance
Offset, blur, spread, color, RGBA opacity, layered shadows.
CSS Border Radius: Corners, Circles & Design
Syntax, values, elliptical corners, guidelines for every element type.
SVG Workflow: View, Optimize & Minify
Complete SVG production pipeline — view, clean editor exports, compress.