Reference & Cheatsheets
427 free reference & cheatsheets tools in the Developer Tools collection — every one runs in your browser with no signup and no uploads. Page 3 of 5.
Kubernetes Pod Phases Reference
Pod phase values — Pending, Running, Succeeded, Failed, Unknown — with transitions.
Kubernetes Probe Types Reference
liveness, readiness, startup probe types with exec, httpGet, tcpSocket, gRPC.
Ladder Safety Class Reference
EN 131 Class I–III and ANSI Type I–III load ratings
World Lakes Area Reference
The 30 largest lakes by surface area with depth and country.
Landlocked Countries Reference
All 44 landlocked countries with surrounding neighbours
Language Family Reference
Major language families with member languages and speaker counts
BCP 47 Language Tag Reference
IETF BCP 47 language tag syntax with subtag types and IANA registry subtags.
LDAP Result Codes Reference
Search LDAP result codes by number or name with RFC source and cause.
Legal Drinking Age by Country Reference
Minimum legal drinking and purchase age for countries worldwide
Life Expectancy by Country Reference
WHO life expectancy at birth for all countries, by sex
Lighthouse Audit Categories Reference
Lighthouse audit IDs, categories and scoring weights for Performance, A11y, SEO
HTTP Link Header Reference
All Link header relation types with rel values, target attributes and use cases.
Linux Capabilities Reference
Every Linux capability constant with the privilege it grants, a typical use, and a risk rating
Linux Filesystem Hierarchy Reference
Key /proc, /sys, /etc, /var paths with purpose and content description.
Linux ip Command Reference
ip addr, ip route, ip link, ip rule subcommands with options and examples.
Linux LVM Commands Reference
pvcreate, vgcreate, lvcreate and lvm management commands with common flags.
Linux mount Options Reference
Common Linux filesystem mount options with scope — generic, ext4, tmpfs, bind.
Linux /proc Files Reference
Key /proc and /proc/PID virtual files with format and data description.
Linux System Calls Reference
Common Linux syscalls with number, signature, errno and man-page reference.
Logic Gate Truth Table Reference
Truth tables for AND, OR, NOT, NAND, NOR, XOR, XNOR
Loki Log Labels & LogQL Reference
LogQL stream selectors, filter expressions and metric query functions.
MAC Algorithm Reference
HMAC, GMAC, Poly1305 MAC algorithms with key sizes and AEAD context.
Makefile Special Variables Reference
All GNU make automatic variables ($@, $<, $^, etc.) with expansion rules.
Material Density Reference
Densities of metals, plastics, woods, and liquids in one table
Drug Schedule Classification Reference
US DEA and UK drug schedules with examples by class
METAR Abbreviation Reference
Decode METAR and TAF codes for sky cover, weather, intensity, and wind.
Military Rank Reference
NATO OF and OR rank codes with US, UK and German equivalents
MIME Type Inspector & Security Risk Checker
Enter a MIME type or file extension and get security, sniffing, and CSP guidance
MIME Type Lookup & File Extension Map
Look up MIME type from extension or extension from MIME type
MIME Types Lookup
Find a MIME type by file extension or search by content-type string.
Common Minerals Reference
Common minerals with hardness, lustre, cleavage and chemical formula.
MLA 9th Edition Citation Reference
Quick-reference format for MLA 9 citations by source type
Mobile Phone Penetration by Country Reference
SIM cards per 100 people for major countries.
Mohs Hardness Scale Reference
All 10 Mohs hardness levels with reference minerals and examples
MongoDB Operators Reference
All MongoDB query, update, aggregation and projection operators in one table.
Morse Code Reference Chart
All letters, digits, and punctuation in International Morse Code
World Mountains Height Reference
The highest mountains with height, range, and country
MQTT Reason Codes Reference
MQTT 5.0 reason codes for CONNECT, PUBLISH, SUBSCRIBE and DISCONNECT.
Musical Note Frequency Reference
Equal-temperament frequencies in Hz for every note from C0 to B8.
MutationObserver Options Reference
childList, attributes, subtree and characterData options with callback entry shape.
NATO Member Reference
All 32 NATO members with accession year and defence spending.
NATO STANAG Reference
Key NATO standardisation agreements by number and subject
NEMA Enclosure Rating Reference
NEMA 1 through 13 ratings with environment suitability
NFC Standard Reference
NFC Forum types 1–5 and ISO 14443 / 15693 standards
NFPA 704 Diamond Reference
Decode NFPA 704 fire diamond ratings for chemicals
nginx Directives Reference
Searchable nginx directive reference with context, syntax and default values.
nginx Built-in Variables Reference
All nginx $variable names with source module and description.
nmap Scan Types Reference
All nmap scan technique flags with stealth level, privilege requirement and use
Node.js EventEmitter Events Reference
Core Node.js built-in event names by module with their payload arguments.
Node.js Stream Events Reference
Readable, Writable, Duplex and Transform stream events with state machine notes.
npm/pnpm Lifecycle Hooks Reference
All npm lifecycle script names in execution order for install, pack and publish.
npm Scripts Reference
Lifecycle npm script hooks in execution order with use cases.
Large Number Names Reference
Million, billion, trillion — short scale vs long scale.
Nut & Spanner Size Reference
Metric and imperial bolt head widths to spanner sizes.
OAuth 2.0 Grant Types Reference
All OAuth 2.0 and PKCE grant types with flows described and security notes.
Ocean & Sea Depth Reference
Average and maximum depths for the world's oceans and major seas.
Olympic Sport Reference
All current Summer and Winter Olympic sports with debut year
OPEC Member Reference
All OPEC members with crude oil production and reserves.
OpenAPI Data Types Reference
OpenAPI 3.1 data types, formats and JSON Schema primitives in one searchable table
OpenID Connect Claims Reference
All OIDC standard claims with data type, scope and example values.
OpenSSL Commands Cheatsheet
Searchable openssl subcommand reference for certs, keys, digests and TLS testing
OWASP Top 10 Reference
All 10 OWASP Web Application Security Risks with descriptions.
Common Oxidation States Reference
Typical oxidation states for every element in the periodic table
Pallet Size Reference
EUR, ISO and US pallet dimensions, material and load capacities.
ISO Paper Sizes Reference
A0–A10 and B0–B10 dimensions in mm, cm, and inches
PCIe Generation Reference
PCIe 1.0 through 7.0 lane speeds and bandwidth
PEM/DER File Types Reference
Crypto file extensions (.pem, .crt, .key, .p12, .jks) with format and content.
Linux perf Events Reference
Common perf hardware, software and tracepoint event names with use cases.
Performance Entry Types Reference
All PerformanceEntry entryType values with their associated API and properties.
Permissions Policy Reference
All Permissions-Policy features with browser support and allowlist syntax.
pH Scale Reference Table
pH values for common substances from battery acid to lye.
IPA Phonetic Symbol Reference
All IPA symbols with example words and Unicode code points
Physical Constants Reference
CODATA values for fundamental physical constants
Pipe Size Reference (NPS / DN)
Nominal pipe sizes with actual OD, wall thickness, and schedules
Solar System Planet Data Reference
Key orbital and physical data for all 8 planets plus dwarf planets.
POSIX Regex Reference
POSIX BRE and ERE syntax compared side-by-side with grep, sed, awk flavor notes
Powers of Two Reference Table
2 to the 0 through 2 to the 63 with decimal and hex values.
Precious Metal Fineness & Hallmark Reference
Gold, silver, and platinum hallmarks to millesimal fineness
Prime Numbers Reference Table
All prime numbers up to 1,000 in a searchable table.
Programming Language Paradigm Reference
OOP, functional, procedural, logic — language paradigms compared.
Project Management Term Reference
PMP and PRINCE2 key terms — WBS, critical path, earned value — with search.
Prometheus Metric Types Reference
Counter, Gauge, Histogram, Summary types with exposition format and PromQL notes.
Public Holidays by Country Reference
National public holidays for major countries, with Easter computed
Python Built-in Functions Reference
Every Python 3 built-in function with signature, return type and what it does
Python Dict Methods Reference
All Python dict methods with signature, return value and 3.7+ order notes
Python Exception Reference
Every built-in Python exception with hierarchy, attributes and typical causes.
Python List Methods Reference
Every Python list method with signature, return value and in-place flag
Python Logging Levels Reference
Python logging level names, numeric values and when to use each level.
Python String Methods Reference
All Python str methods with signature, return type and what they do
Radio Frequency Band Reference
All ITU radio frequency bands with wavelengths and typical uses
React Native Style Props Reference
All React Native style properties with type, platform support and units.
Plastic Recycling Code Reference
Decode resin identification codes 1–7 on plastic packaging.
Redis Commands Reference
All Redis commands filterable by data structure — string, hash, list, set, zset.
Referrer-Policy Values Reference
All Referrer-Policy values with URL exposure behavior and downgrade semantics.
Refractive Index Reference
Optical refractive indices for glass, crystals, and liquids
Regex Lookahead/Lookbehind Reference
Positive/negative lookahead and lookbehind syntax across PCRE, JS, Python, .NET.
Regex Metacharacter Reference
All regex special characters with meaning and example.
Regex Redaction Tester
Write a redaction regex, test it against sample text, and see matched and missed spans
Regex Tokens Cheatsheet
Interactive regex token reference covering PCRE, JS, Python and .NET flavors.
Renewable Energy Capacity by Country Reference
Installed solar, wind, and hydro capacity for top 30 countries.