Guides (320)
Practical deep-dives on the topics our tools cover, JSON, encoding, regex, timestamps, color, CSS and more. Clear explanations, tested code, no fluff.
Latest guides
AVIF Image Format: Better Compression Than WebP and JPEG
AVIF offers 50% smaller files than JPEG at equivalent quality. Learn browser support, how to convert images to AVIF with sharp and ffmpeg, and how to serve AVIF with WebP and...
AWS EventBridge Scheduler: Cron Schedules for Lambda and AWS Services
AWS EventBridge Scheduler runs Lambda functions, ECS tasks, and other AWS targets on a cron or rate schedule. Learn how to create schedules with cron expressions, handle...
Base64 PDF Embedding: Inline PDFs in HTML, JSON APIs, and Email
Embed PDF files as Base64 strings in HTML data URIs, JSON API responses, and email attachments. Learn when Base64 embedding makes sense, the size overhead, and alternatives...
Base64 vs Hex Encoding: When to Use Each
Compare Base64 and hex encoding for binary data. Learn which is more compact, when to use each in APIs, cryptography, and storage, with JavaScript and Python examples.
bcrypt Password Hashing: Why You Should Use bcrypt and How to Implement It
bcrypt is the standard password hashing algorithm for web applications. Learn why MD5 and SHA-256 are wrong for passwords, how bcrypt's work factor prevents brute-force...
Binary Arithmetic: Addition, Subtraction, and Two's Complement
Learn how computers perform binary arithmetic: binary addition with carry, two's complement for negative numbers, overflow detection, and how CPUs handle integer operations in...
Bitmask and Bitwise Operations: Flags, Permissions, and Bit Manipulation
Bitmasks store multiple boolean flags in a single integer using bitwise AND, OR, and XOR. Learn how to set, clear, and check bits for file permissions, feature flags, and game...
CSS Box Shadow Performance: GPU Compositing and Repaint Optimization
Box shadows can hurt scroll and animation performance if used incorrectly. Learn which shadow properties trigger repaints, how to move shadows to the compositor layer, and...
Brute Force Password Attacks: How They Work and How to Defend Against Them
Brute force attacks try every possible password combination. Learn how attackers estimate crack times, why GPU speed matters, how bcrypt/Argon2 slow attacks, and what password...
User-Agent Client Hints: Modern Browser Detection Without UA Sniffing
User-Agent Client Hints replace UA string parsing with structured HTTP headers. Learn how Sec-CH-UA headers work, how to request high-entropy hints, and how to use the...
Critical CSS Inlining: Eliminate Render-Blocking CSS for Faster Load
Critical CSS inlining embeds above-the-fold styles directly in HTML to eliminate render-blocking requests. Learn how to extract critical CSS with tools like critical,...
CSS aspect-ratio Property: Modern Intrinsic Sizing Without Padding Hacks
The CSS aspect-ratio property creates boxes with a fixed width-to-height ratio. Learn how it replaces the padding-top hack, works with images and video embeds, and handles...
CSS flex-order Property: Reorder Flex Items Without Changing HTML
The CSS order property reorders flex items visually without changing the DOM. Learn how to use order for responsive layouts, reverse column order on mobile, and the...
CSV Data Validation: Schema Validation, Type Checking, and Error Reporting
Validate CSV files before importing them into a database or processing pipeline. Learn how to check required columns, validate data types, enforce email/date/numeric formats,...
Import CSV to Database: PostgreSQL, MySQL, SQLite, and Node.js
Import CSV files into PostgreSQL, MySQL, and SQLite using COPY commands, LOAD DATA INFILE, and Node.js streaming inserts. Covers bulk import performance, handling encoding...
CSV with Python pandas: read_csv, to_json, Data Cleaning, and Export
Read, clean, and convert CSV files with Python pandas. Covers pd.read_csv() options, handling missing values, type conversion, filtering, groupby aggregations, and exporting to...
CUID2: Collision-Resistant IDs Better Than UUID v4
CUID2 generates secure, URL-safe, database-friendly IDs with better collision resistance than UUID v4. Learn how CUID2 differs from UUID, nanoid, and ULID, with JavaScript and...
CSS Design Tokens: Define Spacing, Colors, and Typography with Custom Properties
CSS design tokens store reusable values as custom properties (CSS variables). Learn how to define rem-based spacing and type scales, organize tokens by category, and share...
DHCP IP Allocation: How Dynamic IP Assignment Works
DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses, subnet masks, gateways, and DNS servers to devices. Learn how the DORA process works, DHCP lease...
Diceware Passphrases: Stronger and More Memorable Than Passwords
Diceware generates memorable passphrases by rolling dice to select words from a numbered list. Learn why 5-word diceware beats complex passwords, how to generate passphrases in...
Double URL Encoding: What It Is, Why It Happens, and How to Prevent It
Double URL encoding happens when an already-encoded URL is encoded again, turning %20 into %2520. Learn how to detect it, prevent it in APIs and proxies, and why attackers...
Epoch Time Explained: What Is Unix Epoch and Why Does It Start January 1, 1970?
Unix epoch time counts seconds from January 1, 1970 00:00:00 UTC. Learn why 1970 was chosen, how to work with epoch time in JavaScript and Python, the Year 2038 problem, and...
Favicon Caching: Force Browser Refresh After Favicon Change
Browsers aggressively cache favicons, sometimes for days or weeks. Learn how to bust the favicon cache with versioned URLs, HTTP cache headers, and the fastest way to force a...
CSS flex-grow, flex-shrink, flex-basis: The Flex Property Explained
The CSS flex shorthand controls three properties: flex-grow (how much to expand), flex-shrink (how much to contract), and flex-basis (initial size). Learn the common values,...
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