33 SEO-optimized developer guides
In-depth explanations covering databases (SQL, Redis, MongoDB), cryptography (SSH keys, encryption, hashing), data conversion (CSV, YAML, JSON), utilities (URL parsing, email validation, QR codes), and more. Written for search engines and AI agents.
.gitignore Guide: Syntax, Examples, and Patterns for Every Project
Learn how .gitignore works, the pattern syntax, common patterns for Node.js, Python, Java, Go, and macOS, and how to fix files already tracked by git.
HMAC Explained: How to Sign API Requests and Verify Webhook Signatures
Learn what HMAC is, how HMAC-SHA256 works, how to sign HTTP requests with a secret key, and how to verify webhook signatures from services like Stripe and GitHub.
Mock Data Generation: Strategies, Tools, and Best Practices for Testing
Learn how to generate realistic fake data for development and testing: names, emails, dates, UUIDs, addresses, and structured records — without using real user data.
IP Subnet Calculator: CIDR Notation, Subnet Masks, and Network Ranges Explained
Learn how IP subnetting works, how to read CIDR notation, calculate usable host ranges, and why subnetting matters for VPC design, firewalls, and network architecture.
Play Tetris: Classic Block Puzzle Game
Play classic Tetris in your browser. Stack falling Tetrimino pieces, clear lines, and level up.
Play Minesweeper: Classic Puzzle Game
Play classic Minesweeper with three difficulty levels: beginner, intermediate, expert. First click is always safe.
Play Snake: Classic Game Online
Play the classic Snake game in your browser. Eat food, grow your snake, avoid walls and yourself.
TOTP Explained: How Time-Based One-Time Passwords Work
Understand how TOTP (Time-Based One-Time Passwords) generate 6-digit 2FA codes, the cryptography behind them, how to implement TOTP, and how to generate test codes online.
Play Sudoku: 450 Unique Puzzles Online
Play Sudoku with 150 puzzles per difficulty (easy, medium, hard). Sign in to save progress.
Play 2048: Slide and Merge Tiles Online
Slide tiles to merge matching numbers and reach 2048. A classic puzzle game to clear your head between coding.
SVG Optimizer: Minify & Compress SVG Files
Paste SVG markup and minify with SVGO. Remove comments, metadata, default attributes, and whitespace.
Unit Converter: 323 Units Across 43 Categories
Convert between length, mass, pressure, temperature, electrical, and other scientific units. Instant conversion online.
User-Agent Parser: Detect Browser, OS, Device
Paste a User-Agent header to parse browser name/version, OS, device type, and rendering engine instantly.
MIME Type Lookup: Find Content-Type by Extension
Look up MIME/Content-Type for any file extension or filename. Instant lookup, no server required.
Code Snippet Manager: Save & Organize Code Snippets
Save code snippets with syntax highlighting. Auto-detect language, format JSON/SQL, copy with one click.
Docker Compose Guide: Syntax, Examples, and Common Patterns
Learn Docker Compose file syntax field by field. Covers services, networks, volumes, environment variables, health checks, and real-world multi-container patterns.
CSS Gradient Builder: Visual Gradient Generator
Create linear and radial CSS gradients visually. Add color stops, adjust angles, copy CSS instantly.
Image Compressor: Reduce JPEG, PNG, WebP File Size
Compress images locally in your browser with a quality slider. No server upload, instant download.
Text Diff Checker: Compare Text Side by Side
Compare two texts and highlight additions (green) and deletions (red). Fast, browser-based diff tool.
WCAG Contrast Checker: Ensure Text Accessibility
Measure WCAG 2.1 contrast between colors. Check AA and AAA pass/fail for normal and large text.
Color Picker & Converter: HEX, RGB, HSL Online
Pick colors or convert between HEX, RGB, and HSL formats. Generate harmonic palettes (shades, complementary, triadic).
Lorem Ipsum Generator: Placeholder Text for Mockups
Generate Lorem Ipsum text as paragraphs, sentences, words, or lists. Export as plain text or HTML.
Encryption Playground: AES-256-GCM Encrypt/Decrypt Online
Encrypt text using AES-GCM with a passphrase or raw key. Decrypt messages. Educational and client-side secure.
How to Format and Beautify SQL Queries Online
Format messy SQL into readable, indented queries instantly in the browser. Learn SQL formatting conventions, when to use uppercase keywords, and how formatting helps catch bugs.
DNS Lookup: Check A, MX, TXT, NS Records Online
Query DNS records for any domain: A, AAAA, MX, CNAME, TXT, NS, SOA, CAA, and PTR. Instant lookup with TTL and details.
Secret Generator: Create Random API Keys & Tokens Online
Generate cryptographically random secrets, API keys, and tokens with customizable length and alphabet.
URL Encoder/Decoder: Encode Text for URLs & URIs
Percent-encode text for query strings and URI components. Decode encoded text back to readable format. UTF-8 support.
S3 Drive: Browse and Manage AWS S3 Buckets Online
Connect to AWS S3 or DigitalOcean Spaces, browse objects, upload/download files. Credentials encrypted locally before storage.
URL Shortener: Create Short Links with Click Tracking
Shorten long URLs, track clicks, manage your links, and generate QR codes. Private and stored to your account.
JSON Schema Generator: Create Type Models from JSON
Generate JSON Schema or typed models (TypeScript, Python, Go, Rust, Java) from sample JSON instantly. No install required.
Environment Manager: Secure .env Variable Storage
Store and organize environment variables across projects and environments (dev/staging/prod). AES-256 encrypted on your device.
How to Browse and Query MongoDB Online Without Installing a Client
Connect to a MongoDB database, browse collections, run queries, and inspect documents directly in your browser. Learn the basics of NoSQL document querying.
Bookmark Manager: Organize Developer Resources Online
Save and tag your favorite developer links, articles, and tools. Instant access from anywhere without browser clutter.
Markdown Notes: Quick Note-Taking for Developers
Create and organize Markdown notes online with zero friction. Sync across devices, search, and keep your knowledge base accessible.
Task Manager: To-Do List for Developers
Organize your work with a simple, browser-based to-do list. Track tasks, set priorities, and boost productivity without leaving your workflow.
How to Decode SSL Certificates: Read PEM, X.509, CSR Online
Paste an SSL certificate (PEM format) or CSR and inspect subject, issuer, expiry, SANs, and SHA-256 fingerprint instantly.
Redis Commander: CLI Alternative for Connecting & Managing Redis
Connect to Redis instances from your browser. Browse keys, edit values, run commands, and flush patterns. No install needed.
Email Validation: Check Address Format & MX Records
Validate email address format and check MX records instantly. Verify if an email domain has a mail server.
Markdown to HTML: Live Preview & Converter
Write Markdown and preview HTML output side-by-side. Convert Markdown to HTML instantly in your browser.
How to Test a REST API Online Without Postman
Learn how to send API requests, inspect responses, set headers, use authentication tokens, and debug REST endpoints directly in your browser — no desktop install required.
Generate QR Codes Online: Text, URL, WiFi
Create QR codes from URLs, text, WiFi credentials, or vCards instantly. Download as PNG or SVG. No upload, fully browser-based.
Format Converter: JSON to YAML, TOML, XML Online
Convert between JSON, YAML, TOML, and XML instantly. All 12 combinations supported. Validate syntax instantly.
Number Base Converter: Binary, Hex, Decimal, Octal Online
Convert integers between number bases 2-36 instantly. Convert binary to hex, decimal to octal, and more.
Generate SSH Keys Online: Ed25519 vs RSA, OpenSSH Format
Generate Ed25519 or RSA (2048/4096-bit) SSH key pairs in your browser. Download PKCS#8 private keys and OpenSSH public keys instantly.
Convert Images to Base64: Data URI Generator
Convert PNG, JPG, WebP images to Base64 or Data URI instantly. Embed images in HTML and CSS without separate HTTP requests.
Format GraphQL Queries Online: Minify & Pretty Print
Format and minify GraphQL queries, mutations, and subscriptions instantly in your browser. Check syntax and beautify complex queries.
Format YAML Online: Validator & Converter
Format YAML with indentation validation. Convert YAML to JSON and back. Check for syntax errors instantly.
Password Manager for Developers: Secure Storage Without a SaaS Subscription
Learn how developer-focused password managers work, why browser-based encrypted vaults are useful for local credential storage, and how to protect secrets without leaking them.
Convert CSV to JSON, Excel to JSON Online
Upload CSV or Excel files and convert to JSON instantly. Export JSON arrays back to CSV or XLSX. All processing happens in your browser.
URL Parser: Extract URL Components Online
Parse any URL into protocol, host, pathname, query parameters, and hash. Understand URL structure instantly.
Hash Generator: MD5, SHA-256, SHA-512 Online Tool
Generate MD5, SHA-256, SHA-384, SHA-512, and other cryptographic hashes online. Hash text or files instantly in your browser without any upload.
How to Query SQL Databases Online: Connect PostgreSQL, MySQL, MariaDB
Connect to PostgreSQL, MySQL, or MariaDB from your browser. Run SQL queries, explore schemas, and export results without installing a database client. All credentials are AES-256 encrypted.
HTTP Status Codes Explained: A Developer's Reference
Complete guide to HTTP status codes — 1xx, 2xx, 3xx, 4xx, and 5xx — with explanations, common causes, and how to fix the ones you will encounter most as a developer.
AES-256 Encrypted Notes for Developers: What to Store and What to Avoid
A practical guide to AES-256 encrypted notes, vault-style developer data, and when to use MyDevTools Password Manager for sensitive snippets.
Unix Timestamp to Date: Converter, Format Guide, and Common Pitfalls
Learn what Unix timestamps are, how to convert them to human-readable dates in JavaScript, Python, and SQL, and how to avoid the most common timestamp bugs.
Self-Hosted Developer Tools: Why Teams Run Their Own Toolkit
Learn when self-hosted developer tools make sense, what to look for in a private dev toolkit, and how MyDevTools fits self-hosted engineering workflows.
Cron Expression Syntax: Complete Guide with Examples
Learn cron expression syntax field by field with practical examples. Covers standard 5-field cron, extended 6-field formats, special strings, and common patterns for scheduling jobs.
UUID Guide: What They Are, Version Differences, and How to Generate Them
Learn what UUIDs are, the difference between UUID v1, v4, and v7, when to use each, and how to generate UUIDs instantly online without any library.
Base64 Encoding Explained: How It Works and When to Use It
Understand what Base64 encoding is, how it converts binary data to text, common use cases in web development, and how to encode or decode Base64 instantly online.
Regex Lookahead and Lookbehind: Practical Examples
Master regex lookahead and lookbehind assertions with real-world examples. Test patterns in your browser and learn when to use each type of zero-width assertion.
How to Format JSON Online: Beautify, Validate & Minify
Format messy JSON into readable, indented output instantly in the browser. Learn JSON formatting best practices, common errors, and how to minify JSON for production.
How to Decode a JWT Token Online
Learn what a JSON Web Token (JWT) is, how to read its header and payload, and how to decode one instantly in the browser without installing anything.