Developer Reference
Quick reference tables for developers, continuously updated.
Reference index
HTTP Status Codes
Complete 1xx-5xx status code reference with descriptions
ASCII Code Table
Complete 0-127 character code reference
MIME Types Reference
Common Content-Type reference with extensions
HTTP Methods
Safe/idempotent reference for GET/POST/PUT/PATCH/DELETE…
HTML Entities
Named and numeric HTML entities reference
Color Codes
CSS named colors with HEX/RGB and swatches
URL Encoding
Reserved characters and percent-encoding reference
Common Ports
Well-known 0-1023 ports and common services
Regular Expressions
Metacharacters, classes, anchors and quantifiers
Linux Commands
File, process, network and permission commands
Git Commands
clone/commit/branch/merge/rebase reference
HTTP Headers
Request/response header name, kind and meaning
HTML Tags
Structure, text, form, media and semantic tags
File Extensions
Text, code, image, document, media extensions
Character Encodings
UTF-8/GBK/ASCII meaning and usage
Date & Time Formats
Timestamp / ISO 8601 / RFC 3339 examples
SQL Cheat Sheet
SELECT/JOIN/GROUP BY and common statements
Emoji
Emoji categories and meanings
Keyboard Codes
event.key / code / keyCode
Country & Region Codes
ISO 3166 and dialing codes
HTTP Content Types
Content-Type / charset
Language Codes
ISO 639-1 two-letter codes
Currency Codes
ISO 4217 three-letter codes
Docker Commands
run/ps/build/compose/exec reference
Kubernetes Commands
kubectl get/apply/scale/rollout reference
Nginx Config
server/location/proxy_pass/ssl reference
JSON Cheat Sheet
Data types, escaping, JSON.parse and common pitfalls
Image Formats
PNG/JPEG/WebP/AVIF/GIF/SVG compression, transparency and best use
Hash & Encryption
SHA-256/HMAC/bcrypt/Argon2/AES/RSA security and use cases
UUID & Identifiers
UUID v4/v7, ULID and random token formats compared
QR & Barcodes
QR / CODE128 / EAN-13 symbologies and ECC levels
Chart Types
When to use line, bar, pie, scatter and 3 more charts
PDF Guide
14 PDF operations plus page size and DPI charts
Text Processing
9 text operations and the five counting metrics
Calculation & Conversion
Percentage and compound interest traps, temperature scales
Spreadsheet Formats
JSON vs CSV vs HTML plus CSV escaping rules
Naming & Roman Numerals
Eight naming conventions and Roman numeral rules
Network Identifiers
MAC, private IPv4, IPv6 ULA and prefix types
Code Formatting
Formatting limits and indentation, quote, semicolon choices
Markdown Cheat Sheet
Core syntax plus GFM tables and task lists
Developer Utilities
Prompt writing, load testing and camera recording tips
Text-to-Speech
Rate, pitch, voice params and SSML pitfalls
Frequently Asked Questions
What is the Developer Reference?
A set of zero-maintenance evergreen cheat sheets (HTTP status, ASCII, MIME, HTTP methods, HTML entities, color codes) for high-frequency lookups. All render locally in the browser; no data is uploaded.
Is my data uploaded?
No. Every reference page is static content rendered locally in your browser; nothing is collected or uploaded.
How do I find a code quickly?
Each table has a search box to filter by key, name or description in real time; breadcrumbs link between tables.