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Developer & Engineering Reference

38 reference sheets for developers and engineers — HTTP status codes, git, regex, SQL, CSS and JavaScript, plus electronics and mechanical engineering tables. Searchable and mobile-friendly.

Dev & Web18

HTTP Status CodesDev & Web

All 62 HTTP response status codes. Search by code or name, filter by category, copy instantly.

Git Cheat SheetDev & Web

Essential Git commands — setup, branch, merge, remote, stash, undo and more. Search and copy instantly.

Regex Cheat SheetDev & Web

Regular expression syntax — anchors, quantifiers, character classes, groups, lookaheads, flags and common patterns.

SQL Cheat SheetDev & Web

Essential SQL syntax — SELECT, JOINs, aggregates, subqueries, CTEs, DDL, DML, indexes, and transactions.

Unix Command Cheat SheetDev & Web

Essential Unix/Linux shell commands — navigation, file ops, permissions, processes, networking, text processing, pipes and more.

CSS Cheat SheetDev & Web

Essential CSS properties — Layout, Flexbox, Grid, Box Model, Typography, Backgrounds, Animations, Selectors, and Custom Properties.

JavaScript Cheat SheetDev & Web

Modern JavaScript essentials — Variables, Types, Functions, Arrays, Objects, DOM, Async/Await, Promises, and ES Modules.

Docker Cheat SheetDev & Web

Essential Docker commands — images, containers, volumes, networks, Compose, registry, and system cleanup. Search and copy instantly.

Vim Keyboard ShortcutsDev & Web

Essential Vim keybindings — navigation, insert mode, editing, visual mode, search & replace, windows, ex commands, and text objects.

HTTP Headers ReferenceDev & Web

Complete HTTP headers reference — request, response, caching, CORS, security, authentication, and content headers with examples.

TypeScript Cheat SheetDev & Web

TypeScript reference — basic types, interfaces, unions, generics, utility types, type narrowing, enums, and advanced type patterns.

React Cheat SheetDev & Web

React + TypeScript reference — components, props, useState, useEffect, hooks, events, lists, context, and performance patterns.

Tailwind CSS Cheat SheetDev & Web

Tailwind CSS reference — layout, Flexbox, Grid, spacing, sizing, typography, colors, borders, effects, and responsive / dark-mode utilities.

Markdown Cheat SheetDev & Web

Complete Markdown syntax reference with live previews — headings, emphasis, lists, links, images, code, tables, task lists, footnotes and GFM.

Bash & PowerShell ReferenceDev & Web

Side-by-side reference of common Bash and PowerShell commands. Search by task and copy the Bash or PowerShell equivalent with one click.

ASCII Code TableDev & Web

Full ASCII code table (0–127). Look up decimal, hexadecimal, octal, binary, and HTML codes for every control and printable character.

HTML Entities & EmojiDev & Web

HTML entities, special characters, and emoji reference. Copy named entities, numeric references, Unicode code points, or the character itself.

Ports & MIME TypesDev & Web

Reference of common TCP/UDP port numbers and MIME (media) types. Search by port, service, file extension, or content type and copy with one click.

Electronics10

Resistor Color Code CalculatorElectronics

Decode 4, 5 and 6-band resistor color codes both ways — pick band colors to get resistance, tolerance and temperature coefficient, or enter a value to see the bands.

AWG Wire Gauge ChartElectronics

American Wire Gauge reference. Convert AWG to diameter (mm), cross-section (mm²) and approximate current capacity, from 0000 to 40.

Capacitor Code CalculatorElectronics

Convert 3-digit capacitor codes (e.g. 104 → 0.1µF / 100nF) to pF, nF and µF. Includes a full code chart and tolerance letter table.

Enter any two of voltage, current, resistance and power to compute the other two. Uses V=IR, P=VI, P=I²R and P=V²/R with unit-aware inputs.

dB / dBm ConverterElectronics

Convert between dBm and watts, and between power/voltage ratios and decibels. Covers 10·log and 20·log, with a handy reference table (0dBm=1mW, +3dB≈×2).

Logic Gates Truth TableElectronics

Truth tables and symbols for AND, OR, NOT, NAND, NOR, XOR and XNOR — with MIL/ANSI and IEC symbols, Boolean expressions and interactive input toggling.

UART / I2C / SPI ReferenceElectronics

Compare the three embedded serial protocols — signal lines, sync/async, master/slave, speed, full/half duplex and pros & cons, plus common UART baud rates.

Connector Pinouts ReferenceElectronics

Pinouts for common connectors — USB-A/C, RJ45 (T568A/B), DB9 (RS-232), HDMI, 3.5mm TRS/TRRS and Raspberry Pi 40-pin GPIO. Search by connector type.

SI Prefixes (Metric)Electronics

Metric prefix reference from quetta to quecto — symbol, name and power of ten, with a converter (e.g. 4700µF = 4.7mF) and notes on binary prefixes (Ki/Mi).

Battery Sizes & TypesElectronics

Battery size reference — AA/AAA/C/D, 9V, coin cells (CR2032, LR44) and 18650, with dimensions, voltage, capacity, chemistry and IEC/ANSI/JP naming.

Mechanical10

Tap Drill Size ChartMechanical

Tap drill sizes for metric threads — look up the recommended pilot hole diameter for M2–M20 coarse and fine threads by pitch.

Metric Thread Pitch ChartMechanical

Metric thread dimensions for M1–M30 — coarse and fine pitch, pitch diameter and minor diameter. Look up by nominal size.

ISO Tolerance & Fits TableMechanical

ISO limits and fits lookup — find upper and lower deviations (µm) for common hole/shaft symbols like H7, g6 and p6 across size ranges.

Bolt Torque ChartMechanical

Recommended tightening torque for metric bolts (N·m) by nominal size (M3–M20) and property class (4.8, 8.8, 10.9, 12.9). Reference values only.

Hardness Conversion TableMechanical

Approximate hardness conversion for steel — HRC ↔ HB ↔ HV with tensile strength. Look up a value to find the nearest equivalents (ASTM E140 / JIS based).

GD&T Symbols ReferenceMechanical

All 14 geometric tolerance characteristics (ISO 1101 / ASME Y14.5) — symbol, category, datum requirement and meaning, plus datum and modifier symbols.

Surface Roughness (Ra/Rz)Mechanical

Surface roughness reference — approximate Ra ↔ Rz, old triangle symbols, N1–N12 grades and typical machining methods, with ISO 1302 indication notes.

Metal Material Grades (JIS)Mechanical

Common metal material grades — steel (SS400, S45C, SUS304…), aluminum (A5052, A2017, A7075) and copper alloys, with features and typical uses. Searchable.

Drill Size ChartMechanical

Drill bit size conversion — number (1–80), letter (A–Z), fractional and metric (mm) equivalents, with a lookup to find the nearest size in each system.

O-Ring Size ChartMechanical

Common O-ring sizes for JIS B 2401 (P/G/S) and AS568 dash numbers — nominal designation, inner diameter and cross-section (CS), with size lookup.