Guides · page 12 of 14
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URL Query String Guide: Parsing, Building, and Best Practices
URL query strings pass data in URLs after the ? character. Learn how to parse and build query strings in JavaScript, Python, and Go, handle arrays and nested objects, and...
User Agent Detection: Parse Browser and Device from User-Agent String
User agent strings identify the browser, OS, and device making an HTTP request. Here's how to parse user agents reliably, detect mobile vs desktop, and use structured data...
User Agent String Examples: What UA Strings Look Like in 2025
User agent strings identify browsers, operating systems, and devices. Here's what UA strings look like for Chrome, Firefox, Safari, mobile browsers, bots, and crawlers, with...
User Agent String: What Browser User Agents Mean and How to Parse Them
A user agent string identifies the browser, OS, rendering engine, and version making an HTTP request. Here's how to read user agent strings and what each component means.
UUID Collision Probability: How Likely Are Duplicate UUIDs?
UUID v4 has 122 bits of randomness. Collisions are theoretically possible but astronomically unlikely. Here's the math behind UUID uniqueness and when collision risk actually...
UUID Format: Understanding the 128-Bit Unique Identifier Structure
UUIDs follow a specific 8-4-4-4-12 hexadecimal format defined by RFC 4122. Here's what each section of a UUID means, the version and variant bits, and how to parse UUID fields.
UUIDs in Databases: Performance, Storage, and Best Practices
UUIDs as primary keys have real performance implications in PostgreSQL and MySQL. Learn UUID storage size, index fragmentation with random UUIDs, why UUID v7 is better than v4...
UUID v4 Generator: Random UUIDs Explained
UUID v4 uses random bits to generate universally unique identifiers. Here's how v4 differs from other UUID versions, what makes them unique, and when to use UUID v4 vs...
Web Scraping Email Addresses: Ethical Practices and Python Tools
Scrape email addresses from websites ethically using Python requests, BeautifulSoup, and Scrapy. Covers robots.txt compliance, rate limiting, handling JavaScript-rendered...
How to Make a WiFi QR Code: Format, Security and Fixes
A WiFi QR code lets guests join your network by scanning, no password typing. Here's the exact format, how it works, and how to generate one that works on all devices.
Word Frequency Counter: Find Keyword Density and Overused Words
A word frequency counter ranks every unique word by how often it appears. Use it to find keyword density, spot overused words, and diagnose accidental keyword stuffing.
Words Per Minute: Average Reading Speed by Age, Content Type, and Skill
Average adult reading speed is 200-250 words per minute, but it varies dramatically by content type, reader skill, and context. Here's the research and what it means for...
XML vs JSON in API Design: When to Choose Each Format
JSON has largely replaced XML in REST APIs, but XML still dominates in SOAP, enterprise integrations, RSS/Atom, and SVG. Learn when to use XML vs JSON, content negotiation, and...
XML Namespaces: Avoid Element Name Conflicts in XML Documents
XML namespaces prevent element name conflicts when combining XML vocabularies. Here's how namespace declarations work, when you need them, and how to handle namespaces in code.
XML Parsing in JavaScript and Python: DOM, SAX, and XPath
Parse XML in JavaScript using DOMParser and the browser DOM, and in Python using ElementTree, lxml, and BeautifulSoup. Includes XPath queries, handling namespaces, and...
XML to JSON Converter: Transform XML Data to JSON
Converting XML to JSON maps elements, attributes, and text nodes to JSON objects and arrays. Here's how the conversion works, common pitfalls, and how to convert XML to JSON in...
XML vs JSON: Which Data Format Should You Use?
XML and JSON both represent structured data but make different tradeoffs. XML supports attributes, namespaces, and schemas. JSON is lighter, more readable, and native to...
XPath Tutorial: Query XML Documents with Path Expressions
XPath is a query language for selecting nodes from XML documents. It works like CSS selectors for HTML but for XML. Here's XPath syntax, axes, predicates, and functions with...
YAML Anchors and Aliases: Reusing Values with & and *
YAML anchors (&) define a reusable value; aliases (*) reference it. This eliminates repetition in YAML configuration. Here's how to use anchors, aliases, and merge keys (<<) in...
YAML Config Best Practices: Structure, Validation, and Environment Variables
YAML is the dominant format for configuration files in modern software. Here's how to structure YAML configs, validate them with schemas, handle environment variables, and...
YAML in Kubernetes: Writing Kubernetes Manifests
Kubernetes configurations are YAML files called manifests. Here's how Kubernetes YAML is structured, the required fields for common resources (Deployment, Service, ConfigMap),...
YAML Multiline Strings: Literal Block and Folded Scalars
YAML has two multiline string styles: literal block (|) preserves newlines, folded (>) folds newlines into spaces. Here's how to write multiline strings in YAML, control...
YAML Schema Validation: Validate YAML with JSON Schema and Ajv
YAML doesn't have built-in validation, but you can validate YAML structure using JSON Schema after parsing. Here's how to validate YAML files with JSON Schema, Ajv, pydantic,...
YAML Syntax Guide: Indentation, Types, and Common Patterns
YAML syntax uses indentation to define structure. Here's how YAML handles scalars, sequences, mappings, anchors, and multiline strings, with examples for every common pattern.