[{"_1":2,"_1293":-5,"_1294":-5},"loaderData",{"_3":4,"_1281":1282},"en-layout",{"_5":6,"_7":8},"lang","en","page",{"_9":10,"_1094":1095},"tools",{"_11":12,"_13":14,"_15":16,"_17":18,"_242":243,"_557":558,"_651":652,"_719":720,"_814":815,"_1064":1065},"title","Dev Toolbox","subtitle","Handy Tools for Developers","description","The dev toolbox is a web service provides a variety of tools.","math",{"_11":19,"_15":20,"_21":22,"_152":153},"Math Tools","Online math tools including LaTeX equation converter and binary/decimal/hex number converter.","tex",{"_11":23,"_15":24,"_25":26,"_27":28,"_29":30,"_31":32,"_43":44},"Online LaTeX Equation Converter","Type LaTeX expressions and preview equations in real time. 150+ math symbols with one-click input. Download as PNG, SVG, or MathML.","overview","Type LaTeX expressions and preview equations in real time. Download as PNG, SVG, or MathML.","label","Type an expression:","result","Result:","category",{"_33":34,"_35":36,"_37":38,"_39":40,"_41":42},"+/-","Math","∫","Calculus","∩","Sets","Aᵀ","Matrix","αβ","Greek","guide",{"_11":45,"_46":47,"_48":49,"_50":36,"_51":52,"_53":54,"_55":56,"_57":58,"_59":60,"_61":62,"_63":64,"_65":66,"_67":68,"_137":138,"_139":140},"How to Write LaTeX Math","basicTitle","Basic Formulas","basicDesc","LaTeX uses special commands to express mathematical notation. Here are the most commonly used basics.","calculusTitle","calculusDesc","Common notations for integrals, limits, and other calculus expressions.","matrixTitle","Linear Algebra","matrixDesc","Common notations for vectors, dot products, and matrices.","symbolsTitle","Common Greek Letters","symbolsDesc","Greek letters frequently used in math and physics.","descLabel","Description","latexCode","LaTeX Code","renderResult","Result","items",{"_69":70,"_71":72,"_73":74,"_75":76,"_77":78,"_79":80,"_81":82,"_83":84,"_85":86,"_87":88,"_89":90,"_91":92,"_93":94,"_95":96,"_97":98,"_99":100,"_101":102,"_103":104,"_105":106,"_107":108,"_109":110,"_111":112,"_113":114,"_115":116,"_117":118,"_119":120,"_121":122,"_123":124,"_125":126,"_127":128,"_129":130,"_131":132,"_133":134,"_135":136},"fraction","Fraction","exponent","Exponent","subscript","Subscript","squareRoot","Square root","bar","Bar (mean)","hat","Hat (estimate)","derivative","Derivative","partialDerivative","Partial derivative","integral","Definite integral","limit","Limit","summation","Summation","product","Product","vectorArrow","Vector (arrow)","vectorBold","Vector (bold)","dotProduct","Dot product","norm","Norm","parenMatrix","Parenthesized matrix","bracketMatrix","Bracketed matrix","inverseMatrix","Inverse matrix","transposeMatrix","Transpose matrix","alpha","Alpha","beta","Beta","gammaGamma","Gamma","deltaDelta","Delta (change)","epsilon","Epsilon","eta","Eta (learning rate)","theta","Theta","lambda","Lambda","mu","Mu (mean)","piPi","Pi","rho","Rho (density / correlation)","sigmaSigma","Sigma (std. dev. / summation)","phiPhi","Phi","omega","Omega","faqTitle","FAQ","faq",[141,146,149],{"_142":143,"_144":145},"q","What is the difference between LaTeX and TeX?","a","TeX is a typesetting system created by Donald Knuth. LaTeX is a macro package that makes TeX easier to use. Today, \"TeX\" usually refers to LaTeX.",{"_142":147,"_144":148},"My formula is not rendering correctly","Check for missing backslashes (\\) or unclosed braces ({}). Misspelled command names are also a common cause.",{"_142":150,"_144":151},"What is the difference between download formats?","PNG is easy to paste as an image. SVG scales without losing quality. MathML is ideal for web pages and accessibility.","dec2bin",{"_11":154,"_15":155,"_25":156,"_157":158,"_159":160,"_161":162,"_163":164,"_165":166,"_167":168,"_43":169,"_227":228},"Binary Converter - Decimal, Hex & Octal","Online tool to convert between binary, octal, decimal, and hexadecimal number systems. Supports 0b, 0o, and 0x prefix notation.","Enter a number and click Convert to instantly convert between different number bases.","button","Convert","decimal","Decimal","binary","Binary","quaternary","Quaternary","octal","Octal","hex","Hexadecimal",{"_11":170,"_171":172,"_173":174,"_175":176,"_200":201,"_205":206,"_207":208,"_209":210,"_211":212,"_137":216,"_139":217},"Understanding Number Systems","basesTitle","Number Base Comparison","basesDesc","Different number bases are used in various fields of computing and mathematics. Each base has specific advantages.","bases",[177,184,188,192,196],{"_178":179,"_180":181,"_182":183},"name","Binary (Base 2)","digits","0, 1","useCase","Hardware, digital circuits, bitwise operations",{"_178":185,"_180":186,"_182":187},"Quaternary (Base 4)","0–3","DNA encoding, some signal processing",{"_178":189,"_180":190,"_182":191},"Octal (Base 8)","0–7","Unix file permissions (chmod 755)",{"_178":193,"_180":194,"_182":195},"Decimal (Base 10)","0–9","Everyday counting, human-readable values",{"_178":197,"_180":198,"_182":199},"Hexadecimal (Base 16)","0–9, A–F","Memory addresses, color codes (#FF0000), byte representation","baseHeaders",{"_178":202,"_180":203,"_182":204},"Base","Digits","Common Use","howTitle","How Base Conversion Works","howDesc","To convert a number from one base to another, divide the number repeatedly by the target base and collect the remainders. For example, converting decimal 42 to binary: 42 ÷ 2 = 21 remainder 0, 21 ÷ 2 = 10 remainder 1, 10 ÷ 2 = 5 remainder 0, 5 ÷ 2 = 2 remainder 1, 2 ÷ 2 = 1 remainder 0, 1 ÷ 2 = 0 remainder 1. Reading the remainders bottom-up gives 101010.","tipsTitle","Quick Tips for Programmers","tips",[213,214,215],"In most programming languages, prefix 0b denotes binary (0b1010), 0o denotes octal (0o12), and 0x denotes hexadecimal (0xFF).","One hexadecimal digit represents exactly 4 binary digits (bits). For example, 0xF = 0b1111.","CSS/HTML color codes use hex: #FF5733 means R=255, G=87, B=51.","Frequently Asked Questions",[218,221,224],{"_142":219,"_144":220},"Why do computers use binary?","Computers use binary because digital circuits have two states: on (1) and off (0). This maps naturally to electrical signals being high or low voltage.",{"_142":222,"_144":223},"Why is hexadecimal popular in programming?","Hexadecimal is compact (one hex digit = 4 bits) and maps neatly to binary. A byte (8 bits) is exactly 2 hex digits, making memory addresses and byte values easy to read.",{"_142":225,"_144":226},"What is the largest number I can convert?","This tool handles JavaScript's safe integer range (up to 2^53 - 1, or 9,007,199,254,740,991). For most practical purposes, this is more than sufficient.","glossary",[229,233,236,239],{"_11":230,"_231":232},"Bit","body","A bit (binary digit) is the smallest unit of data in computing. It can hold a value of either 0 or 1. Eight bits make one byte.",{"_11":234,"_231":235},"Byte","A byte consists of 8 bits and can represent values from 0 to 255 (or 0x00 to 0xFF in hexadecimal). It is the fundamental unit of data storage.",{"_11":237,"_231":238},"Radix (Base)","The radix, or base, of a number system determines how many unique digits are used. For example, base 10 uses digits 0–9, while base 16 uses 0–9 and A–F.",{"_11":240,"_231":241},"Two's Complement","Two's complement is the most common method for representing signed integers in binary. The most significant bit indicates the sign: 0 for positive, 1 for negative.","text",{"_11":244,"_15":245,"_246":247,"_269":270,"_369":370,"_441":442,"_518":519},"Text Tools","Online text tools including JSON formatter, URL encoder/decoder, JSON diff, and XML pretty printer.","urlencode",{"_11":248,"_15":249,"_25":250,"_27":251,"_252":253,"_157":254,"_29":30,"_227":259},"URL Encoder & Decoder","Online tool to encode and decode URLs (percent-encoding) instantly. Supports Unicode and special characters.","Enter text and press the Encode or Decode button to convert.","Type the text to encode/decode:","placeholder","",{"_255":256,"_257":258},"encode","Encode","decode","Decode",[260,263,266],{"_11":261,"_231":262},"URL Encode (Percent-encoding)","URL encoding (also known as percent encoding) is a technique for converting characters that are either not allowed in URLs or have special meanings into a format that can be safely transmitted.",{"_11":264,"_231":265},"Characters to be encoded","Characters to be encoded include symbols (such as :, /, ?, #, [, ], @, etc.), reserved characters with special meanings, and non-ASCII characters (such as Japanese or other multilingual characters) that cannot be used directly in URLs.",{"_11":267,"_231":268},"Encoding Method","The general encoding method involves first converting the target characters into their byte representation using UTF-8, then converting each byte into its hexadecimal form, and finally prefixing each hex value with a '%' symbol. For example, the Japanese character 'あ' becomes '%E3%81%82'.","json",{"_11":271,"_15":272,"_25":273,"_27":274,"_157":275,"_276":277,"_278":279,"_280":281,"_282":283,"_284":285,"_29":30,"_43":286,"_227":353},"JSON Formatter & Validator","Online JSON formatter, minifier, and validator with syntax highlighting. Format, compress, sort keys, and validate JSON with detailed error messages.","Paste a JSON string and click Format to get a nicely indented and highlighted output. Use Minify to compress, or Sort Keys to alphabetize object keys.","Type the JSON text to format:","Format","minifyButton","Minify","copyButton","Copy","copiedMessage","Copied!","sortKeysLabel","Sort keys","errorLabel","Error",{"_11":287,"_288":289,"_290":291,"_292":293,"_300":301,"_324":325,"_326":327,"_328":329,"_209":334,"_211":335,"_137":216,"_139":340},"JSON Format Guide","syntaxTitle","JSON Syntax Reference","syntaxDesc","JSON (JavaScript Object Notation) supports six data types. All JSON data must be one of these types, and strings must use double quotes.","syntaxHeaders",{"_294":295,"_296":297,"_298":299},"type","Type","syntax","Syntax","example","Example","syntaxItems",[302,306,310,314,317,321],{"_294":303,"_296":304,"_298":305},"Object","{ \"key\": value }","{ \"name\": \"John\" }",{"_294":307,"_296":308,"_298":309},"Array","[ value, ... ]","[1, 2, 3]",{"_294":311,"_296":312,"_298":313},"String","\"text\"","\"hello\"",{"_294":315,"_296":180,"_298":316},"Number","42, 3.14",{"_294":318,"_296":319,"_298":320},"Boolean","true / false","true",{"_294":322,"_296":323,"_298":323},"Null","null","useCasesTitle","Common Use Cases","useCasesDesc","JSON formatting and validation is essential across many development workflows.","useCases",[330,331,332,333],"API development — Inspect and debug API responses by formatting raw JSON payloads.","Configuration files — Format package.json, tsconfig.json, and other config files for readability.","Data transformation — Verify the output of CSV-to-JSON or XML-to-JSON conversions.","Log analysis — Pretty-print structured JSON logs for easier debugging.","Tips",[336,337,338,339],"Use Minify to strip whitespace and reduce file size for production deployments.","Sort Keys alphabetizes object keys, making JSON easier to compare with diff tools.","Error messages show the position of syntax errors so you can fix them quickly.","Trailing commas are invalid in JSON (unlike JavaScript) — remove them before formatting.",[341,344,347,350],{"_142":342,"_144":343},"Is my data safe when using this tool?","Yes. All processing is done entirely in your browser using JavaScript. Your JSON data is never sent to any server.",{"_142":345,"_144":346},"What is the difference between Format and Minify?","Format adds indentation and line breaks for readability. Minify removes all unnecessary whitespace to produce the most compact representation, which is useful for reducing payload size.",{"_142":348,"_144":349},"Why do I get a trailing comma error?","The JSON specification (RFC 8259) does not allow trailing commas after the last element in an object or array. While JavaScript allows them, you must remove trailing commas for valid JSON.",{"_142":351,"_144":352},"Does Sort Keys change array order?","No. Sort Keys only reorders object keys alphabetically. Array element order is preserved because order is significant in JSON arrays.",[354,357,360,363,366],{"_11":355,"_231":356},"JSON (JavaScript Object Notation)","A lightweight, text-based data interchange format derived from JavaScript. It is language-independent and widely used for APIs, configuration files, and data storage. Defined by RFC 8259.",{"_11":358,"_231":359},"JSON Schema","A vocabulary for annotating and validating JSON documents. It defines the structure, data types, and constraints of JSON data, enabling automated validation of API requests and responses.",{"_11":361,"_231":362},"RFC 8259","The IETF standard that defines the JSON data interchange format. It specifies syntax rules such as requiring double quotes for strings and prohibiting trailing commas.",{"_11":364,"_231":365},"Minification","The process of removing all unnecessary whitespace, line breaks, and indentation from JSON (or other code) to reduce file size. Minified JSON is functionally identical to formatted JSON.",{"_11":367,"_231":368},"Trailing Comma","A comma placed after the last element in an object or array. While allowed in JavaScript and some other languages, trailing commas are invalid in the JSON specification and will cause a parse error.","jsonDiff",{"_11":371,"_15":372,"_25":373,"_27":274,"_157":374,"_29":30,"_43":375,"_227":426},"JSON Diff - Compare & Visualize Differences","Online tool to compare two JSON objects and visualize differences. Spot changes in API responses, config files, and database records.","Enter two JSON objects and click Compare to see the differences highlighted.","Compare",{"_11":376,"_377":378,"_379":380,"_381":382,"_398":399,"_324":325,"_326":403,"_328":404,"_209":409,"_410":411,"_211":412,"_137":216,"_139":417},"Understanding JSON Diff","readingTitle","How to Read the Diff Results","readingDesc","The diff output uses symbols and colors to indicate what changed between the two JSON documents.","diffTypes",[383,390,394],{"_384":385,"_386":387,"_388":389},"symbol","+ (green)","operation","ADD","meaning","A new key or value exists in the second JSON that is not in the first.",{"_384":391,"_386":392,"_388":393},"- (red)","REMOVE","A key or value exists in the first JSON but not in the second.",{"_384":395,"_386":396,"_388":397},"- / + (red then green)","UPDATE","A value changed — the old value is shown in red and the new value in green.","diffTypeHeaders",{"_384":400,"_386":401,"_388":402},"Symbol","Operation","Meaning","JSON diff comparison is essential for developers working with structured data.",[405,406,407,408],"API response comparison — Compare responses from different API versions or environments to spot breaking changes.","Config file changes — Verify configuration differences between staging and production environments.","Data migration validation — Ensure data integrity by comparing records before and after migration.","Code review — Quickly identify what changed in JSON-based fixtures, mocks, or test data.","Tips for Accurate Comparison","tipsDesc","Follow these tips to get the most accurate diff results. The tool automatically formats your JSON before comparing, but proper input helps you interpret results more easily.",[413,414,415,416],"Ensure both inputs are valid JSON — the tool will show a syntax error if parsing fails.","Key order does not affect the diff — only values and structural differences are detected.","Arrays are compared by index — reordering array elements will show as changes.","Nested objects are compared recursively — differences at any depth level are detected.",[418,420,423],{"_142":342,"_144":419},"Yes. All comparison is performed entirely in your browser using JavaScript. Your JSON data is never sent to any server.",{"_142":421,"_144":422},"Does key order matter in the comparison?","No. JSON objects are unordered by specification, so {\"a\":1,\"b\":2} and {\"b\":2,\"a\":1} are considered identical. Only actual value differences are shown.",{"_142":424,"_144":425},"Can I compare JSON arrays?","Yes. You can compare JSON arrays as well as objects. Arrays are compared element by element based on their index position.",[427,430,433,436,439],{"_11":428,"_231":429},"Learn about JSON","JSON stands for JavaScript Object Notation and is a lightweight data interchange format. It is a text-based data format that is used to exchange data between different computer systems, applications and programming languages.",{"_11":431,"_231":432},"JSONPath","JSONPath is a query language for JSON, similar to XPath for XML. It allows you to select and extract specific elements from a JSON document using path expressions like $.store.book[0].title.",{"_11":434,"_231":435},"Diff Algorithm","A diff algorithm computes the minimum set of changes needed to transform one data structure into another. For JSON, this involves recursively comparing objects and arrays to detect additions, removals, and value updates at every level of nesting.",{"_11":437,"_231":438},"Nested Object","A nested object is a JSON object contained within another object as a value. For example, {\"user\": {\"name\": \"Alice\"}} has a nested object. JSON diff tools compare nested structures recursively to detect changes at any depth.",{"_11":358,"_231":440},"JSON Schema is a vocabulary for annotating and validating JSON documents. It defines the expected structure, data types, and constraints of a JSON document, making it useful for API contract validation and data quality assurance.","xml",{"_11":443,"_15":444,"_25":445,"_27":446,"_157":275,"_29":30,"_278":279,"_280":281,"_43":447,"_227":502},"XML Formatter & Pretty Printer","Online tool to format and indent XML documents with syntax highlighting for easy reading and debugging.","Paste your XML document and click Format to get a nicely indented output with syntax highlighting.","Type the XML document to format:",{"_11":448,"_288":449,"_290":450,"_292":451,"_300":454,"_324":325,"_326":479,"_328":480,"_209":334,"_211":485,"_137":216,"_139":490},"XML Format Guide","XML Syntax Reference","XML (Extensible Markup Language) uses a tree structure of nested elements. Every XML document must have exactly one root element, and all tags must be properly closed.",{"_452":453,"_296":297,"_298":299},"construct","Construct",[455,459,463,467,471,475],{"_452":456,"_296":457,"_298":458},"Element","content","Alice",{"_452":460,"_296":461,"_298":462},"Attribute","","",{"_452":464,"_296":465,"_298":466},"Self-closing","","
",{"_452":468,"_296":469,"_298":470},"Comment","","",{"_452":472,"_296":473,"_298":474},"CDATA","","",{"_452":476,"_296":477,"_298":478},"Declaration","","","XML formatting is useful in many development and data exchange scenarios.",[481,482,483,484],"API debugging — Inspect and format SOAP/REST XML responses for easier analysis.","Configuration files — Format Maven pom.xml, Spring beans, and other config files for readability.","Data interchange — Verify XML exports from databases, spreadsheets, or enterprise systems.","SVG editing — Pretty-print SVG graphics files to understand and modify their structure.",[486,487,488,489],"XML is case-sensitive — and are different elements.","Attribute values must always be quoted with single or double quotes.","Special characters like <, >, and & must be escaped as <, >, and & in text content.","Use CDATA sections to include blocks of text that contain many special characters without escaping.",[491,493,496,499],{"_142":342,"_144":492},"Yes. All processing is done entirely in your browser using JavaScript. Your XML data is never sent to any server.",{"_142":494,"_144":495},"What is the difference between XML and HTML?","XML is a strict, extensible markup language for data representation, while HTML is designed for displaying web pages. XML requires all tags to be closed and is case-sensitive, whereas HTML is more lenient.",{"_142":497,"_144":498},"Can this tool validate XML?","This tool checks for well-formedness (proper nesting and closing of tags). It does not validate against an XML Schema (XSD) or DTD.",{"_142":500,"_144":501},"What indentation does the formatter use?","The formatter uses 2-space indentation by default, which is the most common convention for XML documents.",[503,506,509,512,515],{"_11":504,"_231":505},"XML (Extensible Markup Language)","A markup language for encoding documents in a human-readable and machine-readable format. XML is a W3C standard widely used for data interchange between systems, configuration files, and document formats like SVG and XHTML.",{"_11":507,"_231":508},"Well-formed XML","An XML document that follows all syntax rules: it has exactly one root element, all tags are properly nested and closed, attribute values are quoted, and element names are case-sensitive. A well-formed document can be parsed by any XML parser.",{"_11":510,"_231":511},"XML Schema (XSD)","A W3C standard for defining the structure, content, and data types of XML documents. Unlike DTD, XSD itself is written in XML and supports data types, namespaces, and complex type definitions.",{"_11":513,"_231":514},"Namespace","A mechanism to avoid element name conflicts by qualifying names with a URI. Declared using the xmlns attribute (e.g., xmlns:xsl=\"http://www.w3.org/1999/XSL/Transform\"), namespaces enable combining elements from different vocabularies in a single document.",{"_11":516,"_231":517},"XSLT","Extensible Stylesheet Language Transformations (XSLT) is a language for transforming XML documents into other formats such as HTML, plain text, or different XML structures. It uses template rules to match and process elements.","charCounter",{"_11":520,"_15":521,"_25":522,"_27":523,"_252":524,"_157":525,"_526":527,"_29":528,"_227":544},"Character Counter - Count Characters, Words & Lines Instantly","Paste text and instantly count characters (with/without spaces), words, sentences, lines, and paragraphs. Perfect for Twitter/X posts, essays, SEO meta tags, and more.","Type or paste text to instantly see character count, line count, paragraph count, and more.","Enter text:","Type or paste your text here","Count","resetButton","Reset",{"_529":530,"_531":532,"_533":534,"_535":253,"_536":537,"_538":539,"_540":541,"_542":543},"charsWithSpaces","Characters (with spaces)","charsWithoutSpaces","Characters (without spaces)","words","Words","wordsNote","sentences","Sentences","lines","Lines","paragraphs","Paragraphs","manuscriptPages","Manuscript pages",[545,547,549,551,553,555],{"_11":530,"_231":546},"The total number of all characters in the text, including spaces, line breaks, and symbols. Useful for checking character limits on platforms like X (Twitter) or HTML meta description length.",{"_11":532,"_231":548},"The number of characters excluding all whitespace (spaces, tabs, and line breaks). Useful when you need a pure character count for reports or assignments with strict character requirements.",{"_11":534,"_231":550},"The number of words separated by spaces. This metric is most accurate for languages that use spaces between words, such as English. It may not produce meaningful results for languages like Japanese or Chinese.",{"_11":537,"_231":552},"The number of sentences determined by sentence-ending punctuation (. ! ? and their full-width equivalents). Useful as a measure of text density and readability.",{"_11":541,"_231":554},"The number of non-empty lines in the text (lines that contain at least one visible character). Useful for understanding the structure and organization of your writing.",{"_11":539,"_231":556},"The total number of lines in the text, including empty lines. Useful for counting lines of code or understanding the overall size of a text file.","coding",{"_11":559,"_15":560,"_561":562},"Coding Tools","Online coding tools including Scheme playground for running Lisp code in your browser.","scheme",{"_11":563,"_15":564,"_25":565,"_27":566,"_157":567,"_29":30,"_43":568,"_227":632},"Scheme Playground - Online IDE","Run Scheme (Lisp) code instantly in your browser. Great for SICP exercises, lambda calculus, and learning functional programming.","Type your Scheme code and click Run to see the output instantly.","Type the code:","Run",{"_11":569,"_570":571,"_572":573,"_574":575,"_606":607,"_608":609,"_610":611,"_612":613,"_137":216,"_139":619},"Scheme Programming Guide","basicsTitle","Basic Syntax","basicsDesc","Scheme uses prefix notation (also called Polish notation) where the operator comes before the operands, all wrapped in parentheses.","examples",[576,582,586,590,594,598,602],{"_11":577,"_578":579,"_580":581},"Arithmetic","code","(+ 1 2 3) ; => 6\n(* 4 5) ; => 20\n(- 10 3) ; => 7\n(/ 15 3) ; => 5","desc","Basic math operations. Operators can take multiple arguments.",{"_11":583,"_578":584,"_580":585},"Variables","(define x 42)\n(define name \"hello\")\nx ; => 42","Use define to bind values to names.",{"_11":587,"_578":588,"_580":589},"Functions","(define (square x)\n (* x x))\n(square 5) ; => 25","Define functions with (define (name args...) body).",{"_11":591,"_578":592,"_580":593},"Conditionals","(if (> 3 2)\n \"yes\"\n \"no\") ; => \"yes\"\n\n(cond\n ((< x 0) \"negative\")\n ((= x 0) \"zero\")\n (else \"positive\"))","Use if for simple conditions, cond for multiple branches.",{"_11":595,"_578":596,"_580":597},"Lists","(list 1 2 3) ; => (1 2 3)\n(car '(1 2 3)) ; => 1\n(cdr '(1 2 3)) ; => (2 3)\n(cons 0 '(1 2)) ; => (0 1 2)","Lists are the fundamental data structure. car returns the first element, cdr returns the rest.",{"_11":599,"_578":600,"_580":601},"Lambda (Anonymous Functions)","; Anonymous function\n((lambda (x) (* x x)) 5) ; => 25\n\n; Assign lambda to variable\n(define double\n (lambda (x) (* x 2)))\n(double 7) ; => 14\n\n; Higher-order function\n(map (lambda (x) (+ x 1))\n '(1 2 3)) ; => (2 3 4)","Lambda creates unnamed functions. Essential for functional programming patterns like map and filter.",{"_11":603,"_578":604,"_580":605},"Recursion","(define (fibonacci n)\n (if (<= n 1)\n n\n (+ (fibonacci (- n 1))\n (fibonacci (- n 2)))))\n(fibonacci 10) ; => 55","Scheme relies heavily on recursion instead of loops.","examplesTitle","Code Examples","examplesDesc","Try these examples in the playground above. Click Run to see the results.","conceptsTitle","Key Concepts","concepts",[614,615,616,617,618],"Everything is an expression — Every piece of Scheme code returns a value, including if statements and definitions.","First-class functions — Functions can be passed as arguments, returned from other functions, and stored in variables.","Tail call optimization — Scheme guarantees that tail-recursive functions run in constant stack space, making recursion as efficient as loops.","Lexical scoping — Variables are resolved in the environment where they are defined, not where they are called.","Minimalist design — Scheme has very few special forms. Most functionality is built from a small set of primitives.",[620,623,626,629],{"_142":621,"_144":622},"What is the difference between Scheme and Common Lisp?","Scheme is minimalist with a single namespace and guaranteed tail call optimization. Common Lisp is larger with separate namespaces for functions and variables, and a more extensive standard library. Scheme emphasizes elegance and simplicity.",{"_142":624,"_144":625},"Why are there so many parentheses?","Parentheses in Scheme define the structure of the code (S-expressions). This uniform syntax makes the language easy to parse and enables powerful metaprogramming with macros. Most editors provide auto-matching to make them manageable.",{"_142":627,"_144":628},"Is Scheme still used today?","Yes. Scheme is widely used in computer science education (e.g., the classic textbook SICP). Languages like Racket (a Scheme descendant) are actively developed. Guile Scheme is used as an extension language in GNU software.",{"_142":630,"_144":631},"Does the code run on a server?","No. All code runs entirely in your browser using the LIPS Scheme interpreter (JavaScript-based). Nothing is sent to any server.",[633,636,639,641,644,648],{"_11":634,"_231":635},"Scheme","Scheme is a classic programming language in the Lisp family, created in 1975 by Guy L. Steele and Gerald Jay Sussman at MIT. It is known for its clean, minimalist design and is widely used in computer science education.",{"_11":637,"_231":638},"S-expression","An S-expression (symbolic expression) is the basic syntax unit in Lisp languages. It is either an atom (like a number or symbol) or a list of S-expressions enclosed in parentheses, such as (+ 1 2).",{"_11":124,"_231":640},"Lambda creates an anonymous (unnamed) function. For example, (lambda (x) (* x x)) creates a function that squares its argument. The name comes from lambda calculus, the mathematical foundation of functional programming.",{"_11":642,"_231":643},"Tail Call Optimization","Tail call optimization (TCO) is a technique where the compiler/interpreter reuses the current stack frame for a function call in tail position. This allows recursive functions to run without growing the call stack, preventing stack overflow errors.",{"_11":645,"_231":646,"_647":-7},"SICP","Structure and Interpretation of Computer Programs is a legendary textbook by Harold Abelson and Gerald Jay Sussman. Originally used at MIT, it teaches fundamental programming concepts using Scheme and is freely available online.","link",{"_11":649,"_231":650},"LIPS Interpreter","This playground uses LIPS (Lisp In Parentheses Syntax), a Scheme interpreter written in JavaScript. It supports most R7RS Scheme features and runs entirely in the browser.","network",{"_11":653,"_15":654,"_655":656},"Network Tools","Online network tools including IP address checker with geolocation map display.","ipLocation",{"_11":657,"_15":658,"_25":659,"_43":660,"_227":706},"IP Address & Location Checker","Detect your IP address (IPv4/IPv6) and display your approximate location on a map. Useful for network diagnostics and privacy checks.","Automatically detects your IP address and approximate location, displayed on an interactive map.",{"_11":661,"_662":663,"_664":665,"_666":667,"_681":682,"_687":688,"_689":690,"_324":325,"_328":691,"_137":216,"_139":696},"Understanding IP Addresses","versionsTitle","IPv4 vs IPv6","versionsDesc","There are two versions of the Internet Protocol in use today.","versions",[668,676],{"_178":669,"_670":671,"_672":673,"_674":675},"IPv4","format","192.168.1.1","addressSpace","About 4.3 billion addresses","status","Most widely used, but addresses are exhausted",{"_178":677,"_670":678,"_672":679,"_674":680},"IPv6","2001:0db8:85a3::8a2e:0370:7334","Virtually unlimited (3.4×10^38)","Gradually being adopted worldwide","versionHeaders",{"_178":683,"_670":684,"_672":685,"_674":686},"Version","Format Example","Address Space","Status","whatIsTitle","What Does Your IP Address Reveal?","whatIsDesc","Your IP address can reveal your approximate geographic location, Internet Service Provider (ISP), and the type of network you are using. However, it does not reveal your exact street address or personal identity.",[692,693,694,695],"VPN verification — Confirm your VPN is working by checking if your IP address has changed.","Troubleshooting — Diagnose network issues by identifying your public IP and ISP information.","Geolocation testing — Verify how websites and services detect your location.","Security audits — Check what information your IP address exposes to the internet.",[697,700,703],{"_142":698,"_144":699},"Why does the location shown not match my exact location?","IP geolocation is approximate and typically accurate to the city or region level. Your ISP may route your traffic through a nearby data center, so the displayed location may be the ISP's facility rather than your home.",{"_142":701,"_144":702},"What is the difference between a public and private IP address?","A public IP address is assigned by your ISP and is visible on the internet. Private IP addresses (like 192.168.x.x or 10.x.x.x) are used within your local network and are not directly accessible from the internet.",{"_142":704,"_144":705},"Can someone find my exact location from my IP address?","No. IP geolocation only provides an approximate location, usually at the city level. Only your ISP can map your IP to your physical address, and they are legally required to protect that information.",[707,710,713,716],{"_11":708,"_231":709},"IP Address","An Internet Protocol (IP) address is a numerical label assigned to each device connected to a network. It serves two main purposes: identifying the host and providing the location of the host in the network.",{"_11":711,"_231":712},"ISP (Internet Service Provider)","An ISP is a company that provides internet access to customers. Your ISP assigns your public IP address and can see your internet traffic unless it is encrypted.",{"_11":714,"_231":715},"AS Number (ASN)","An Autonomous System Number identifies a network or group of networks under a single administrative entity. ISPs and large organizations each have their own ASN.",{"_11":717,"_231":718},"Geolocation","IP geolocation is the process of determining the geographic location of a device based on its IP address. Accuracy varies from country-level to city-level depending on the database used.","security",{"_11":721,"_15":722,"_723":724,"_801":802},"Security Tools","Online security tools including SHA hash generator and AI-powered file type detector.","hash",{"_11":725,"_15":726,"_25":727,"_728":729,"_730":731,"_157":732,"_43":733,"_227":785},"SHA Hash Generator (SHA1/SHA256/SHA512)","Generate SHA1, SHA256, SHA384, and SHA512 hash values online. Supports HMAC. All processing happens in your browser for maximum security.","All hash generation is performed in your browser — your data is never sent to a server or stored anywhere.","label1","Type the text to generate:","label2","HMAC(Optional):","Generate",{"_11":734,"_735":736,"_737":738,"_739":740,"_760":761,"_324":325,"_326":766,"_328":767,"_772":773,"_774":775,"_137":216,"_139":776},"Understanding Hash Functions","algorithmTitle","Algorithm Comparison","algorithmDesc","SHA family algorithms differ in output length, security level, and performance. Choose the right algorithm for your use case.","algorithms",[741,747,752,756],{"_178":742,"_743":744,"_719":745,"_182":746},"SHA-1","output","160 bits (40 hex)","Deprecated","Legacy systems only",{"_178":748,"_743":749,"_719":750,"_182":751},"SHA-256","256 bits (64 hex)","Secure","Digital signatures, SSL/TLS, Bitcoin",{"_178":753,"_743":754,"_719":750,"_182":755},"SHA-384","384 bits (96 hex)","Government, high-security applications",{"_178":757,"_743":758,"_719":750,"_182":759},"SHA-512","512 bits (128 hex)","Maximum security, large data integrity","algorithmHeaders",{"_178":762,"_743":763,"_719":764,"_182":765},"Algorithm","Output Length","Security","Use Case","Hash functions are fundamental to modern security and data integrity verification.",[768,769,770,771],"Password storage — Store hashed passwords instead of plain text for secure authentication.","File integrity — Verify downloaded files have not been corrupted or tampered with by comparing checksums.","Digital signatures — Hash the message before signing to ensure authenticity and integrity.","Data deduplication — Identify duplicate data blocks using their hash values for efficient storage.","hmacTitle","What is HMAC?","hmacDesc","HMAC (Hash-based Message Authentication Code) combines a hash function with a secret key to verify both data integrity and authenticity. Unlike a simple hash, HMAC ensures the message was sent by someone who possesses the secret key. It is widely used in API authentication, JWT tokens, and secure communication protocols.",[777,780,782],{"_142":778,"_144":779},"What is the difference between SHA-256 and SHA-512?","SHA-256 produces a 256-bit hash and SHA-512 produces a 512-bit hash. SHA-512 provides stronger security but SHA-256 is sufficient for most applications. On 64-bit systems, SHA-512 can actually be faster than SHA-256.",{"_142":342,"_144":781},"Yes. All hash generation is performed entirely in your browser using the Web Crypto API. Your data is never sent to any server.",{"_142":783,"_144":784},"Can a hash be reversed to get the original text?","No. Hash functions are one-way — it is computationally infeasible to reverse a hash back to its original input. This is what makes them useful for password storage.",[786,789,792,795,798],{"_11":787,"_231":788},"SHA (Secure Hash Algorithm)","The Secure Hash Algorithm (SHA), abbreviated as SHA, is also known as a cryptographic hash function. It has been designated as the standard hash function, Secure Hash Standard, by the National Institute of Standards and Technology (NIST) in the United States. SHA transforms any large data block into a fixed-size output (typically much shorter than the input).",{"_11":790,"_231":791},"Warning","SHA-1 is now considered vulnerable and should not be used for cryptographic applications.",{"_11":793,"_231":794},"Hash Collision","A hash collision occurs when two different inputs produce the same hash output. Modern algorithms like SHA-256 are designed to make collisions extremely unlikely — the probability is approximately 1 in 2^128.",{"_11":796,"_231":797},"Salt","A salt is random data added to the input of a hash function before hashing. It prevents attackers from using precomputed tables (rainbow tables) to crack password hashes. Each password should have a unique salt.",{"_11":799,"_231":800},"HMAC (Hash-based Message Authentication Code)","HMAC is a mechanism for calculating a message authentication code using a hash function combined with a secret key. It provides both data integrity and authentication, ensuring that the message has not been altered and was sent by someone with the key.","fileScanner",{"_11":803,"_15":804,"_25":805,"_157":806,"_227":807},"File Type Detector - Dr.Filescan","Detect file types using AI-powered analysis by Google Magika. All processing happens in your browser — files are never uploaded.","Drop files to detect their types. All processing happens in your browser — files are never uploaded anywhere.","Scan file(s)",[808,811],{"_11":809,"_231":810},"Lean about Magika","Magika is a tool to detect common file content types, using deep learning. View project on “https://google.github.io/magika/”.",{"_11":812,"_231":813},"Disclaimer","The service provider has no affiliation with the developers or organizations behind Magika and is solely using it for the purpose of library validation. This service is intended for validating Magika and is not designed for detecting malware in files. The results of file scans are indicative and do not guarantee their accuracy.","geo",{"_11":816,"_15":817,"_818":819,"_898":899,"_990":991},"GIS & Geography Tools","Online GIS tools: WKT/GeoJSON converter & viewer, SHP to GeoJSON converter, and Geocode map viewer. All browser-based.","geocode",{"_11":820,"_15":821,"_25":822,"_823":824,"_825":826,"_827":828,"_829":830,"_27":831,"_43":838,"_227":888},"Lat/Lng to Geocode Converter & Map Viewer","Online tool to convert latitude/longitude to Plus Codes, Quadkey, Geohash, and Grid Square Code. Visualize geocode grids on an interactive map.","Enter latitude and longitude to convert to various geocode formats and visualize grids on the map.","openlocationcode","Open Location Code","quadkey","Quadkey","geohash","Geohash","jisgrid","Grid Square Code",{"_832":833,"_834":835,"_836":837},"radio","Grid type","lnglat","Longitude and latitude","level","Zoom level",{"_11":839,"_840":841,"_842":843,"_844":845,"_851":852,"_205":869,"_207":870,"_324":871,"_328":872,"_137":138,"_139":878},"Understanding Geocoding Systems","comparisonTitle","Geocode Format Comparison","comparisonDesc","Several geocoding systems exist, each with different characteristics regarding precision, coverage, and intended use cases.","comparisonHeaders",{"_178":275,"_846":847,"_848":849,"_182":850},"precision","Precision","developer","Developer","Primary Use Case","comparison",[853,857,861,865],{"_178":824,"_846":854,"_848":855,"_182":856},"~14m × 14m (10-digit)","Google","Sharing locations without street addresses",{"_178":826,"_846":858,"_848":859,"_182":860},"Tile-level dependent","Microsoft","Bing Maps tile indexing and caching",{"_178":828,"_846":862,"_848":863,"_182":864},"~1.2km to ~2cm","Gustavo Niemeyer","Proximity search and database indexing",{"_178":830,"_846":866,"_848":867,"_182":868},"~1km to ~125m","JIS (Japan)","Japanese statistical and administrative data","How Geocoding Works","Geocoding systems encode latitude and longitude into compact strings by recursively dividing the Earth's surface into smaller grids. Each character in the resulting code narrows down the area, providing progressively finer precision. This approach enables efficient spatial indexing, fast proximity queries, and easy sharing of location information without requiring full coordinate pairs.","Use Cases",[873,874,875,876,877],"Sharing precise locations in areas without formal street addresses","Efficient proximity searches in geospatial databases","Delivery and logistics location pinpointing","Map tile management and caching in web mapping services","Statistical analysis using standardized geographic grid units",[879,882,885],{"_142":880,"_144":881},"What is a Plus Code?","Plus Code is Google's consumer-facing name for Open Location Code. It encodes any location into a short alphanumeric string (e.g., \"8Q7XMQH2+39\"). The \"+\" separates the area code from the local code. Plus Codes are useful for identifying locations in areas without formal addresses.",{"_142":883,"_144":884},"Which format provides the highest precision?","Geohash offers the most flexible precision — adding more characters increases accuracy from ~1.2km down to a few centimeters. Open Location Code provides ~14m precision at 10 digits. The best choice depends on your use case rather than raw precision alone.",{"_142":886,"_144":887},"Can Grid Square Code be used outside Japan?","Yes. The \"World Mesh\" system extends JIS X 0410 (Grid Square Code) globally by dividing the world into 8 regions. The encoding method is identical, and Japanese mesh codes can be derived by removing the first two digits of the world mesh code.",[889,892,894,896],{"_11":890,"_231":891},"Open Location Code (Plus Codes)","The Open Location Code is a geocode based in a system of regular grids for identifying an area anywhere on the Earth. It was developed at Google's Zürich engineering office, and released late October 2014. Location codes created by the Open Location Code system are referred to as \"plus codes\".",{"_11":826,"_231":893},"Quadkey (Quadtree Key) is a geolocation hashing algorithm developed by Microsoft that divides regions based on latitude and longitude into grids of approximately the same size. Each quadkey has a single-digit code, zero to three. By zooming into the next level, each of the four original quadkeys splits into four, and we add another digit to the code.",{"_11":828,"_231":895},"Geohash is a method of encoding geographic location into a short string of characters. The encoded string represents a grid-based approximation of the location, allowing for fast and efficient indexing and retrieval of geographic data.",{"_11":830,"_231":897},"The grid square code is a method of dividing a geographic area into a grid of smaller regions for the purpose of organizing and efficiently accessing geographic data. The grid square code is an extension of the standardized regional grid square code developed in Japan (JIS X 0410), expanded to a global scale.","wktGeojson",{"_11":900,"_15":901,"_25":902,"_27":903,"_43":908,"_227":975},"WKT to GeoJSON Converter & Map Viewer","Online WKT playground to convert WKT to GeoJSON (and back) and view on an interactive map. Supports PostGIS, SQL Server, and other GIS data.","Enter WKT or GeoJSON to convert between formats and view the result on an interactive map. Supports FeatureCollection to GEOMETRYCOLLECTION conversion.",{"_904":905,"_906":907},"wkt","WKT(Well-known text)","geojson","GeoJSON",{"_11":909,"_910":911,"_912":913,"_914":915,"_919":920,"_606":941,"_608":942,"_574":943,"_209":334,"_211":960,"_137":138,"_139":965},"WKT & GeoJSON Guide","formatsTitle","Format Comparison","formatsDesc","WKT and GeoJSON are the two most common formats for representing geospatial data. Understanding their differences helps you choose the right format for your workflow.","formatHeaders",{"_916":917,"_904":918,"_906":907},"feature","Feature","WKT","formats",[921,925,929,933,937],{"_916":922,"_904":923,"_906":924},"Format type","Plain text","JSON",{"_916":926,"_904":927,"_906":928},"Primary use","Databases (PostGIS, SQL Server)","Web APIs & frontends",{"_916":930,"_904":931,"_906":932},"Geometry types","POINT, LINESTRING, POLYGON, ...","Point, LineString, Polygon, ...",{"_916":934,"_904":935,"_906":936},"Attribute data","Not supported","Stored in \"properties\"",{"_916":938,"_904":939,"_906":940},"Standard","OGC / ISO 19162","RFC 7946","WKT Examples","Here are common WKT geometry types you can paste into the converter above.",[944,948,952,956],{"_11":945,"_904":946,"_580":947},"Point","POINT(139.7671 35.6812)","A single coordinate point (Tokyo Station)",{"_11":949,"_904":950,"_580":951},"LineString","LINESTRING(139.7671 35.6812, 139.6917 35.6895, 139.7454 35.6586)","A line connecting two or more points",{"_11":953,"_904":954,"_580":955},"Polygon","POLYGON((139.74 35.67, 139.78 35.67, 139.78 35.70, 139.74 35.70, 139.74 35.67))","A closed area (first and last coordinates must match)",{"_11":957,"_904":958,"_580":959},"MultiPoint","MULTIPOINT((139.7671 35.6812), (135.5023 34.6937))","Multiple separate points (Tokyo and Osaka)",[961,962,963,964],"Polygon coordinates must form a closed ring — the first and last points must be identical.","GeoJSON coordinates use [longitude, latitude] order, same as WKT.","In PostGIS, use ST_AsText() for WKT and ST_AsGeoJSON() for GeoJSON conversion.","Use FeatureCollection to group multiple geometries with their properties into a single GeoJSON document.",[966,969,972],{"_142":967,"_144":968},"Should I use WKT or GeoJSON?","Use WKT for database storage and SQL queries (PostGIS, SQL Server). Use GeoJSON for web APIs, frontend map rendering, and data exchange between web services. Many tools support both, so the choice depends on your primary workflow.",{"_142":970,"_144":971},"What is the coordinate order?","Both WKT and GeoJSON use longitude first, then latitude (e.g., POINT(139.7 35.6) or [139.7, 35.6]). This differs from Google Maps and many GPS devices which display latitude first.",{"_142":973,"_144":974},"Can 3D coordinates be handled?","Yes. WKT supports POINT Z(139.7 35.6 100) for 3D coordinates. GeoJSON includes the altitude as the third element in the coordinates array: [139.7, 35.6, 100]. Note that altitude support varies across tools.",[976,979,981,984,987],{"_11":977,"_231":978},"WKT (Well-Known Text)","WKT stands for Well-Known Text, which is a text representation of spatial data used in Geographic Information Systems (GIS). WKT is a standard format for describing geometric objects like points, lines, polygons, and multi-polygons in a way that is both human-readable and machine-readable. WKT is often used to exchange spatial data between different GIS systems or to store geometry information in databases.",{"_11":907,"_231":980},"GeoJSON (Geographic JavaScript Object Notation) is a lightweight data interchange format for representing geographic spatial data. Based on the JSON format, GeoJSON is well-suited for expressing geographical shapes on a map. It combines the human-readable and machine-parseable features of JSON and is defined by RFC 7946.",{"_11":982,"_231":983},"PostGIS","PostGIS is an open-source spatial database extension for PostgreSQL. It adds support for geographic objects, allowing location queries to be run in SQL. PostGIS supports both WKT and GeoJSON formats and is one of the most widely used GIS databases.",{"_11":985,"_231":986},"OGC (Open Geospatial Consortium)","The Open Geospatial Consortium is an international organization that develops open standards for geospatial data. WKT, WKB, and many other spatial data formats and protocols are defined as OGC standards.",{"_11":988,"_231":989},"FeatureCollection","A FeatureCollection is a GeoJSON object type that contains an array of Feature objects. Each Feature has a geometry (Point, Polygon, etc.) and a properties object for attribute data. FeatureCollections are the standard way to represent multiple geographic features in a single GeoJSON document.","shpGeojson",{"_11":992,"_15":993,"_25":994,"_27":995,"_43":999,"_227":1049},"SHP/Shapefile to GeoJSON Converter & Map Viewer","Online tool to convert Shapefile (.shp) to GeoJSON. Upload a ZIP, get WGS84 GeoJSON with map preview. Works with ArcGIS, QGIS, and other GIS tools.","Upload a Shapefile (.shp) as a ZIP file and click Convert to transform it to GeoJSON (WGS84) and preview on the map.",{"_996":997,"_906":998},"shp","Shapefile(zip file format)","List of converted GeoJSON file[s]",{"_11":1000,"_1001":1002,"_1003":1004,"_1005":1006,"_1011":1012,"_1030":1031,"_1032":1033,"_209":334,"_211":1034,"_137":138,"_139":1039},"Shapefile & GeoJSON Guide","componentsTitle","Shapefile Components","componentsDesc","A Shapefile is not a single file but a collection of files with the same base name and different extensions. Understanding these components helps ensure successful conversion.","componentHeaders",{"_1007":1008,"_1009":1010,"_15":62},"extension","Extension","required","Required","components",[1013,1016,1019,1022,1026],{"_1007":1014,"_1009":1010,"_15":1015},".shp","Geometry data (points, lines, polygons)",{"_1007":1017,"_1009":1010,"_15":1018},".shx","Spatial index for the geometry",{"_1007":1020,"_1009":1010,"_15":1021},".dbf","Attribute data (dBASE format)",{"_1007":1023,"_1009":1024,"_15":1025},".prj","Recommended","Coordinate system / projection definition",{"_1007":1027,"_1009":1028,"_15":1029},".cpg","Optional","Character encoding specification","conversionTitle","About the Conversion","conversionDesc","This tool reads Shapefile ZIP archives and converts them to GeoJSON (WGS84). If a .prj file is included, the coordinates are automatically reprojected to WGS84 (EPSG:4326). Attribute data from the .dbf file is preserved in the GeoJSON \"properties\" field. If no .prj file is present, coordinates are assumed to already be in WGS84.",[1035,1036,1037,1038],"Include .shp, .shx, and .dbf files in the ZIP archive — all three are required.","Always include the .prj file for correct coordinate system transformation.","If attribute data contains non-ASCII characters, include a .cpg file specifying the encoding (e.g., UTF-8, Shift_JIS).","The converted GeoJSON files can be downloaded and used in QGIS, Leaflet, Mapbox, and other GIS tools.",[1040,1043,1046],{"_142":1041,"_144":1042},"Which files should I include in the ZIP?","At minimum, include .shp, .shx, and .dbf files. We strongly recommend also including .prj (coordinate system) and .cpg (character encoding) for correct results. All files must share the same base name.",{"_142":1044,"_144":1045},"Is the coordinate system converted automatically?","Yes, if a .prj file is included in the ZIP, coordinates are automatically reprojected to WGS84 (EPSG:4326), the standard for GeoJSON. Without a .prj file, the tool assumes coordinates are already in WGS84.",{"_142":1047,"_144":1048},"How large a Shapefile can be converted?","Since all processing happens in the browser, the practical limit depends on your device's memory. Files up to around 50MB typically work well. For very large datasets, consider using desktop tools like QGIS or ogr2ogr.",[1050,1053,1055,1058,1061],{"_11":1051,"_231":1052},"Shapefile","Shapefile is a widely used geospatial vector data format developed by ESRI. A Shapefile consists of multiple files (.shp, .shx, .dbf, .prj, etc.) that together represent geometry, spatial index, attribute data, and coordinate system information. It is the de facto standard for exchanging vector GIS data.",{"_11":907,"_231":1054},"GeoJSON (Geographic JavaScript Object Notation) is a lightweight data interchange format for representing geographic spatial data. Based on the JSON format, it supports Point, LineString, Polygon, and collection types. Defined by RFC 7946, it is widely used in web mapping applications.",{"_11":1056,"_231":1057},"WGS84 (EPSG:4326)","WGS84 (World Geodetic System 1984) is the standard coordinate reference system used by GPS. It defines latitude and longitude on an ellipsoidal model of the Earth. EPSG:4326 is the identifier code for WGS84. GeoJSON requires all coordinates to be in WGS84.",{"_11":1059,"_231":1060},"EPSG Code","EPSG codes are numeric identifiers for coordinate reference systems, maintained by the International Association of Oil & Gas Producers. Common examples include EPSG:4326 (WGS84), EPSG:3857 (Web Mercator), and EPSG:2451 (JGD2000 Japan Zone 9). The .prj file in a Shapefile defines which coordinate system is used.",{"_11":1062,"_231":1063},"dBASE (.dbf)","dBASE is a legacy database file format used by Shapefiles to store attribute data. The .dbf file contains tabular data associated with each geometric feature. While the format is old, it remains essential for Shapefile compatibility and is read by all GIS software.","web",{"_11":1066,"_15":1067,"_1068":1069},"Web Tools","Online web tools including OGP checker for meta tags and Twitter Card validation.","seo",{"_11":1070,"_15":1071,"_25":1072,"_27":1073,"_157":1074,"_29":30,"_227":1075},"OGP Checker - Meta Tags & Twitter Card Validator","Online OGP checker to validate meta tags, Twitter Cards, and robots.txt. Preview how your page appears on Facebook, X (Twitter), and LinkedIn.","Enter a URL and click Check to inspect OGP tags, meta tags, and Twitter Card settings.","Page URL to check:","Check",[1076,1079,1082,1085,1088,1091],{"_11":1077,"_231":1078},"What is OGP?","OGP (Open Graph Protocol) is a metadata standard that controls how your content appears when shared on social networks like Facebook. By setting og:title, og:description, and og:image, you can customize the link preview display.",{"_11":1080,"_231":1081},"What are Twitter Cards?","Twitter Cards control how link previews appear when shared on X (Twitter). You can specify card types (summary, summary_large_image, etc.) using twitter:card. If OGP tags are set, they serve as fallbacks when Twitter-specific tags are not present.",{"_11":1083,"_231":1084},"Recommended OGP Image Size","The recommended OGP image size for both Facebook and X is 1200×630px (aspect ratio 1.91:1). File size should be under 5MB, and supported formats include JPG, PNG, GIF, and WebP.",{"_11":1086,"_231":1087},"What is robots.txt?","robots.txt is a file that instructs search engine crawlers which pages on your site they can or cannot access. It is placed at the site root and uses User-agent with Disallow/Allow rules for control.",{"_11":1089,"_231":1090},"What is a Canonical Tag?","A canonical tag tells search engines which URL is the authoritative version when duplicate content exists. Specified as , it prevents SEO value from being diluted across multiple URLs.",{"_11":1092,"_231":1093},"OGP Not Updating?","Social networks cache OGP information, so updates may not reflect immediately. Use Facebook's Sharing Debugger or X's Card Validator to clear the cache. Also, ensure og:image URLs use absolute paths.","games",{"_11":1096,"_13":1097,"_15":1098,"_1099":1100,"_1107":1108,"_1115":1116,"_1133":1134,"_1146":1147,"_1222":1223,"_1241":1242,"_1264":1265,"_1272":1273},"Bit Games","Browser Mini Games","Quick, casual games for whenever you have a moment. All games work on both desktop and mobile browsers.","features",{"_1101":1102,"_1103":1104,"_1105":1106},"free","Runs in browser","noInstall","Desktop & mobile","mobile","Mobile friendly","categories",{"_1109":1110,"_1111":1112,"_1113":1114},"puzzle","Puzzle","arcade","Arcade","simulation","Simulation","minesweeper",{"_11":1117,"_15":1118,"_25":1119,"_1120":1121,"_1122":1123,"_1127":1128,"_1129":1130},"Minesweeper - Classic Puzzle Game","Play Minesweeper online. Three difficulty levels: Beginner, Intermediate, and Expert. Works on mobile.","A classic puzzle game where you clear a minefield without detonating any mines.","placeFlag","Place a flag","levels",[1124,1125,1126],"Beginner","Intermediate","Expert","rulesTitle","Rules","rules",[1131,1132],"The board is divided into cells, with mines randomly distributed. To win, you need to open all the cells. The number on a cell shows the number of mines adjacent to it. Using this information, you can determine cells that are safe, and cells that contain mines. Cells suspected of being mines can be marked with a flag check the 'Place a flag'.","To start a new game, you can click on the Reset button at the top of the board. The remaining number of mines is displayed in the left corner, and the game timer is displayed in the right corner.","invaders",{"_11":1135,"_15":1136,"_25":1137,"_1138":1139,"_1127":1128,"_1129":1140},"Space Invaders - Retro Arcade Game","Play a classic Space Invaders-style arcade game. Arrow keys to move, Space to shoot. Stage-based gameplay, works on desktop and mobile.","A classic arcade game inspired by Space Invaders. Destroy all the invaders before they reach you!","controls","Controls: Arrow keys to move, Space to shoot",[1141,1142,1143,1144,1145],"Destroy all invaders to clear the stage. Invaders move left and right, gradually descending.","Use the arrow keys to move your ship left and right. Press the Space key to fire bullets.","Barriers will protect you from enemy fire, but they gradually break down when hit.","If an invader reaches your position or you are hit by enemy fire, the game is over.","Click the screen to start the next level after clearing a stage.","automaton",{"_11":1148,"_15":1149,"_43":1150,"_227":1209},"Cellular Automaton Simulators","Explore cellular automaton simulations: Conway's Game of Life and all 256 Elementary Cellular Automaton rules. Runs in your browser.",{"_11":1151,"_1152":1153,"_1154":1155,"_1156":1157,"_1158":1159,"_1160":1161,"_1165":1166,"_1183":1184,"_1185":1186,"_1187":1188,"_1189":1190,"_137":138,"_139":1196},"What Are Cellular Automata?","introTitle","Overview","introDesc","Cellular automata (CA) are discrete computational models consisting of a grid of cells, each in one of a finite number of states. At each time step, every cell updates its state simultaneously based on a fixed rule that considers the states of its neighboring cells. Despite their simplicity, cellular automata can produce remarkably complex behaviors — from stable patterns to chaotic dynamics — making them a powerful tool for studying emergence and self-organization.","typesTitle","Types of Cellular Automata","typesDesc","Cellular automata come in many forms depending on their dimensionality, neighborhood definition, and rule structure.","typeHeaders",{"_178":295,"_1162":1163,"_298":1164},"dimensions","Dimensions","Notable Example","types",[1167,1171,1175,1179],{"_178":1168,"_1162":1169,"_298":1170},"Elementary CA","1D","Wolfram's 256 rules (Rule 30, Rule 110)",{"_178":1172,"_1162":1173,"_298":1174},"Totalistic CA","1D / 2D","Rules based on sum of neighbor states",{"_178":1176,"_1162":1177,"_298":1178},"Life-like CA","2D","Conway's Game of Life (B3/S23)",{"_178":1180,"_1162":1181,"_298":1182},"Continuous CA","2D+","Lenia, SmoothLife","historyTitle","Brief History","historyDesc","Cellular automata were first studied by Stanislaw Ulam and John von Neumann in the 1940s at Los Alamos National Laboratory. Von Neumann was interested in self-replicating systems and designed a 2D CA capable of universal computation. In 1970, John Conway created the Game of Life, which became widely popular and demonstrated how complex behavior emerges from simple rules. In the 1980s, Stephen Wolfram systematically studied elementary cellular automata, classifying their behavior into four classes and proposing that simple programs can generate complexity comparable to natural phenomena.","applicationsTitle","Applications","applications",[1191,1192,1193,1194,1195],"Modeling physical phenomena (crystal growth, fluid dynamics, diffusion)","Biological simulations (population dynamics, pattern formation)","Cryptography and random number generation (Rule 30)","Traffic flow simulation and urban planning","Theoretical computer science (computation universality, complexity theory)",[1197,1200,1203,1206],{"_142":1198,"_144":1199},"Are cellular automata Turing complete?","Some are. Rule 110 in elementary cellular automata and Conway's Game of Life have been proven to be Turing complete, meaning they can simulate any computation that a Turing machine can perform.",{"_142":1201,"_144":1202},"What is the difference between Game of Life and Elementary CA?","Game of Life operates on a 2D grid where each cell has 8 neighbors (Moore neighborhood) and uses birth/survival rules. Elementary CA operates on a 1D row where each cell has 2 neighbors, with 256 possible rule sets. Both are deterministic zero-player systems.",{"_142":1204,"_144":1205},"Who invented cellular automata?","The concept was developed by Stanislaw Ulam and John von Neumann in the 1940s. Von Neumann designed a self-replicating CA as a theoretical model for biological reproduction. The field gained popular attention with Conway's Game of Life (1970) and Wolfram's systematic studies (1980s).",{"_142":1207,"_144":1208},"Can I use these simulators on mobile?","Yes. Both the Game of Life and Elementary CA simulators run entirely in your browser and are responsive. Performance depends on your device, but modern smartphones handle them well.",[1210,1213,1216,1219],{"_11":1211,"_231":1212},"Cellular Automaton","A cellular automaton (plural: cellular automata, abbrev. CA) is a discrete model of computation consisting of a grid of cells, each in one of a finite number of states. Cells update simultaneously based on the states of their neighbors according to a fixed rule. CAs are studied in automata theory, complexity science, and mathematical biology.",{"_11":1214,"_231":1215},"Conway's Game of Life","The Game of Life is a 2D cellular automaton created by mathematician John Horton Conway in 1970. It uses simple birth/survival rules (B3/S23): a dead cell with exactly 3 neighbors becomes alive, and a living cell with 2 or 3 neighbors survives. It is Turing complete and has been extensively studied for its emergent complexity.",{"_11":1217,"_231":1218},"Elementary Cellular Automaton","An elementary cellular automaton (ECA) is a 1D CA where each cell has two possible states and the next state depends on the cell and its two immediate neighbors. There are 256 possible rules (numbered 0–255). Some rules produce simple patterns, while others like Rule 30 and Rule 110 generate complex, chaotic, or universal behavior.",{"_11":1220,"_231":1221},"Wolfram Classification","Stephen Wolfram classified elementary cellular automata into four behavioral classes: Class 1 (uniform), Class 2 (periodic), Class 3 (chaotic/random), and Class 4 (complex/edge of chaos). Rule 110, a Class 4 automaton, was proven Turing complete by Matthew Cook in 2004.","life",{"_11":1224,"_15":1225,"_25":1226,"_1127":1128,"_1129":1227,"_1233":1234,"_1235":1236},"Conway's Game of Life Simulator","Experience Conway's Game of Life simulator in your browser. Glider, Pulsar, Glider Gun, Pentadecathlon and more patterns. High-speed Bitboard algorithm.","A simulation game modeling the birth, evolution, and extinction of life. Experience high-speed generation updates with the Bitboard algorithm.",[1228,1229,1230,1231,1232],"The universe of the Game of Life is an infinite, two-dimensional orthogonal grid of square cells, each of which is in one of two possible states, live or dead (or populated and unpopulated, respectively). ","1. Any live cell with two or three live neighbours survives.","2. Any dead cell with three live neighbours becomes a live cell.","3. All other live cells die in the next generation. Similarly, all other dead cells stay dead.","It is a zero-player game, meaning that its evolution is determined by its initial state, requiring no further input. One interacts with the Game of Life by creating an initial configuration and observing how it evolves. It is Turing complete and can simulate a universal constructor or any other Turing machine.","aboutTitle","What is Conway's Game of Life?","about",[1237,1238,1239,1240],"The Game of Life is a cellular automaton devised by British mathematician John Horton Conway in 1970. On a two-dimensional grid, cells with two states — alive or dead — evolve through generations following four simple rules.","The only input from the player is the initial configuration; after that, the system evolves automatically, which is why it is called a \"zero-player game.\" A hallmark of the Game of Life is that remarkably complex patterns emerge from simple rules.","Patterns in the Game of Life fall into three main categories: still lifes (Block, Beehive, etc.), oscillators (Blinker, Pulsar, etc.), and spaceships (Glider, Lightweight Spaceship, etc.). The Glider, which travels across the grid indefinitely, is perhaps the most iconic pattern.","The Game of Life has been proven to be Turing complete, meaning it can theoretically simulate any computer program. This property makes it an important model in computation theory, complex systems science, and artificial life research.","eca",{"_11":1243,"_15":1244,"_25":1245,"_27":1246,"_1127":1257,"_1129":1258},"Elementary Cellular Automaton Simulator","Explore all 256 rules of Elementary Cellular Automaton in your browser. Visualize fractal, chaotic, and self-similar patterns from simple rules.","Elementary cellular automata play an important role in the field of computation theory. Among them, there exist ECA rules that have computational power equivalent to a universal Turing machine, and they are considered to be the simplest form of a universal computing model. Additionally, there are ECA rules that generate fractal-like self-similar patterns or chaotic behaviors, garnering attention in the study of complex systems. The fact that they produce complex behaviors from simple rules is thought to be useful for modeling natural phenomena.",{"_1247":1248,"_1249":1250,"_1251":1252,"_1253":1254,"_1255":1256},"rule","Rule number(0-255)","initialState","Initial state","initialStateSingle","Single bit","initialStateRandom","Random","pattern","State transition pattern","Rules of an elementary cellular automaton",[1259,1260,1261,1262,1263],"A one-dimensional array of cells is given","Each cell is assigned a value of either 0 or 1","The state of a particular cell at time t+1 is determined by the states of that cell itself and its two neighboring cells (left and right) at time t","A rule is defined that specifies the next state (0 or 1) for each of the 8 possible combinations of the states of the three cells (center, left neighbor, right neighbor): 111, 110, 101, 100, 011, 010, 001, 000","Therefore, there are 2^8 = 256 possible ruleset specifications","tetrimimus",{"_11":1266,"_15":1267,"_25":1268,"_1127":1128,"_1129":1269},"Tetrimimus - Tetris-style Falling Blocks","Play a falling-block puzzle game in your browser. Studies show that just 3 minutes of block-puzzle play can reduce stress.","A falling-block puzzle game. Rotate and move blocks to clear lines. Research suggests that short sessions of block-puzzle games can help reduce stress. Give your tired brain a 3-minute refresh.",[1270,1271],"A single-sided tetromino block piece, constructed by combining four squares, falls randomly from the upper part of the field, one type at a time.","When any 1 to 4 rows of the grid are completely filled with blocks, those rows disappear, and points are awarded based on the number of rows cleared. Clearing multiple rows simultaneously (up to 4 rows) results in higher points.","pacBoy",{"_11":1274,"_15":1275,"_25":1276,"_1127":1128,"_1129":1277},"Pac-Boy - 1D Pac-Man Style Dot-Eating Game","Play Pac-Boy, a 1D dot-eating game inspired by Pac-Man. A remake of ABA Games' PAKU PAKU.","A 1D dot-eating game similar to Pac-Man. Eat dots while evading enemies.",[1278,1279,1280],"The player's goal is to eat as many dots as possible while evading the enemies.","After eating a large dot, the player can eat the enemies for a limited time.","Once all the dots have been eaten, new dots will appear.","en-tools-web",{"_5":6,"_9":1283},{"_11":12,"_1064":1284},{"_11":1066,"_15":1067,"_1068":1285},{"_11":1070,"_15":1071,"_25":1072,"_27":1073,"_157":1074,"_29":30,"_227":1286},[1287,1288,1289,1290,1291,1292],{"_11":1077,"_231":1078},{"_11":1080,"_231":1081},{"_11":1083,"_231":1084},{"_11":1086,"_231":1087},{"_11":1089,"_231":1090},{"_11":1092,"_231":1093},"actionData","errors"]