Developer Tools

Format, validate, convert and generate — JSON, XML, YAML, CSV, HTML, CSS and code utilities that run entirely in your browser, so nothing you paste leaves your machine. 193 tools, grouped by topic.

Reviewed by the CalcCafe editorial team · Last updated 1 July 2026 · How we test our tools

JSON tools

View, format, validate, minify, escape and diff JSON.

JSON Tools OnlineA free suite of online JSON tools: parser, reader, viewer, editor, tree, minifier, stringify,…
JSON EditorFree online JSON editor.
JSON ViewerFree online JSON viewer.
JSON ParserFree online JSON parser.
JSON Reader OnlineFree JSON reader.
JSON TreeFree JSON tree viewer.
JSON Tree ViewerPaste JSON and explore it as an interactive, collapsible tree — expand and collapse any node, with…
JSON MinifyFree JSON minifier.
JSON EscapeFree JSON escape tool.
JSON UnescapeFree JSON unescape tool.
JSON DiffCompare two JSON documents and see exactly what was added, removed or changed.
JSON to StringFree JSON to string converter.
JSON Stringify OnlineFree online JSON stringify tool.
JSON URL EncodeFree JSON URL encoder.
JSON URL DecodeFree JSON URL decoder.
JSON5 FormatterFree JSON5 formatter.
JSON5 ValidatorFree JSON5 validator.
JSON to JSON SchemaGenerate a JSON Schema (draft-07) from any JSON sample.

XML tools

Edit, pretty-print, minify, validate and escape XML.

XML Tools OnlineA free suite of online XML tools: formatter, pretty-printer, parser, viewer, editor, minifier, validator,…
XML EditorEdit XML with live validation, formatting and minifying.
XML ViewerExplore XML as a collapsible tree of elements and attributes.
XML ParserParse and validate XML, then format it — with clear error messages.
XML FormatterFormat and indent messy or minified XML into clean, readable markup.
XML Pretty PrintPretty-print XML with clean indentation for easy reading.
XML MinifyCompact XML by removing whitespace between elements.
XML EscapeEscape XML special characters so text is safe inside markup.
XML UnescapeDecode XML entities back to their original characters.
XML ValidatorCheck whether XML is well-formed, with precise error messages.
XML URL EncodePercent-encode XML so it's safe in a URL or query string.
XML URL DecodeDecode percent-encoded XML back into readable markup.
XML to JSON SchemaConvert XML into a JSON Schema (draft-07) right in your browser.

YAML tools

Parse, format and validate YAML.

YAML Tools OnlineA free suite of YAML tools: formatter, viewer, parser, validator, converters and code generation — all in…
YAML ParserParse and validate YAML in your browser.
YAML ViewerParse YAML and explore it as a collapsible, colour-coded tree right in your browser.
YAML FormatterClean up and reformat YAML in your browser.
YAML ValidatorValidate YAML syntax instantly in your browser.
YAML URL EncodeURL-encode YAML text with encodeURIComponent so it can safely travel inside query strings, form bodies, or…
YAML URL DecodeDecode percent-encoded (URL-encoded) YAML back to readable text using decodeURIComponent.
YAML to JSON SchemaPaste YAML and instantly infer a JSON Schema (draft-07) with types, nested objects, arrays, and required…

Data format converters

Move data between JSON, XML, YAML, CSV, TSV, HTML and Base64.

CSV to JSON ConverterConvert CSV to JSON online for free.
JSON to CSV ConverterConvert JSON to CSV online for free.
JSON to XML ConverterConvert JSON to XML online for free.
XML to JSON ConverterConvert XML to JSON online for free.
JSON to YAML ConverterConvert JSON to YAML online for free.
YAML to JSON ConverterConvert YAML to JSON online for free.
XML to YAMLConvert XML to YAML in your browser.
YAML to XMLConvert YAML to XML in your browser.
CSV to XMLConvert CSV with a header row into clean, well-formed XML.
XML to CSVConvert XML to CSV right in your browser.
CSV to YAMLConvert CSV data into clean YAML.
YAML to CSVConvert a YAML array of objects into CSV instantly in your browser.
CSV to HTML TableConvert CSV data into a clean, semantic HTML table with thead and tbody.
JSON to TSVConvert a JSON array of objects to TSV (tab-separated values).
RSS to JSONConvert RSS or Atom feed XML into clean, structured JSON with channel metadata and an items array.
Excel (TSV) to HTML TablePaste rows copied from Excel or Google Sheets and instantly turn the tab-separated data into a clean HTML…
Base64 to JSONDecode Base64 (Unicode-safe) and pretty-print the result as JSON.
JSON to Base64Encode JSON text to Base64 in your browser.
Base64 to XMLDecode Base64 back into XML text in your browser.
XML to Base64Encode XML text to a Base64 string in your browser.
Base64 to YAMLDecode Base64 back to YAML text in your browser.
YAML to Base64Encode YAML (or any text) to Base64 with full Unicode support.
CSV EscapeEscape a field value for CSV per RFC 4180: quote if it has commas, quotes, or newlines, and double any…
CSV UnescapeUnescape quoted CSV fields: strip surrounding double quotes and collapse doubled quotes ("") back to a…

JSON to code (classes & types)

Generate typed models from a JSON sample in Go, Java, Python, TypeScript, C#, Kotlin, Swift, Dart, Rust and more.

Data to Code GeneratorsGenerate type definitions, structs and classes from XML and YAML for 18 languages plus JSON Schema.
JSON to GoConvert JSON into idiomatic Go struct definitions with json tags.
JSON to JavaConvert JSON into idiomatic Java classes.
JSON to PythonConvert JSON into idiomatic Python dataclasses with inferred types.
JSON to TypeScriptConvert JSON into idiomatic TypeScript interfaces.
JSON to C#Convert JSON into idiomatic C# classes.
JSON to KotlinConvert JSON to idiomatic Kotlin data classes.
JSON to SwiftConvert JSON into idiomatic Swift structs.
JSON to DartConvert JSON into idiomatic Dart classes with type inference, fromJson factories, nested objects, and…
JSON to RustConvert JSON into idiomatic Rust structs with serde derives.
JSON to RubyConvert JSON into idiomatic Ruby classes with type-annotated accessors.
JSON to C++Convert JSON into idiomatic C++ structs.
JSON to ElmConvert JSON into idiomatic Elm type aliases.
JSON to FlowConvert JSON into idiomatic Flow type definitions.
JSON to PikeConvert JSON into idiomatic Pike class definitions.
JSON to CrystalConvert JSON into idiomatic Crystal structs with JSON::Serializable.
JSON to HaskellConvert JSON into idiomatic Haskell record types.
JSON to Objective-CConvert JSON into idiomatic Objective-C @interface class declarations.
JSON to JavaScript PropTypesConvert JSON into idiomatic React PropTypes definitions.

XML to code

Typed models from an XML sample.

XML to GoConvert XML into idiomatic Go structs with xml tags.
XML to JavaConvert XML into idiomatic Java classes.
XML to PythonConvert XML into idiomatic Python dataclasses.
XML to TypeScriptConvert XML into TypeScript interface definitions.
XML to C#Convert XML into idiomatic C# classes.
XML to KotlinConvert XML into idiomatic Kotlin data classes.
XML to SwiftConvert XML into idiomatic Swift Codable structs.
XML to DartConvert XML into idiomatic Dart classes.
XML to RustConvert XML into idiomatic Rust structs.
XML to RubyConvert XML into idiomatic Ruby Struct definitions.
XML to C++Convert XML into idiomatic C++ structs.
XML to ElmConvert XML into Elm type aliases.
XML to FlowConvert XML into Flow type definitions.
XML to PikeConvert XML into idiomatic Pike type definitions.
XML to CrystalConvert XML into idiomatic Crystal structs with JSON::Serializable.
XML to HaskellConvert XML into idiomatic Haskell record types.
XML to Objective-CConvert XML into idiomatic Objective-C model classes.
XML to JavaScript PropTypesConvert XML into React PropTypes definitions.

YAML to code

Typed models from a YAML sample.

YAML to GoConvert YAML into Go struct definitions instantly.
YAML to JavaConvert YAML into idiomatic Java class definitions.
YAML to PythonConvert YAML into idiomatic Python type definitions.
YAML to TypeScriptConvert YAML into TypeScript interfaces.
YAML to C#Convert YAML into idiomatic C# class definitions in your browser.
YAML to KotlinConvert YAML into idiomatic Kotlin data classes.
YAML to SwiftConvert YAML into idiomatic Swift structs.
YAML to DartConvert YAML into idiomatic Dart classes.
YAML to RustConvert YAML into idiomatic Rust structs and enums.
YAML to RubyPaste YAML and instantly generate idiomatic Ruby Struct definitions.
YAML to C++Convert YAML into idiomatic C++ struct definitions.
YAML to ElmConvert YAML into idiomatic Elm type aliases.
YAML to FlowConvert YAML into Flow type definitions.
YAML to PikeConvert YAML into idiomatic Pike type definitions.
YAML to CrystalConvert YAML into Crystal struct definitions.
YAML to HaskellConvert YAML into idiomatic Haskell record type definitions.
YAML to Objective-CConvert YAML into Objective-C model classes.
YAML to JavaScript PropTypesConvert YAML into React PropTypes definitions.

HTML tools

Format, validate, minify and escape HTML; convert to and from Jade/Pug.

HTML EditorEdit HTML with a live preview and one-click formatting.
HTML ViewerRender HTML in a sandboxed live preview as you type.
HTML FormatterFormat and indent messy or minified HTML into clean, readable markup.
HTML Pretty PrintPretty-print HTML with clean indentation so it's easy to read and review.
HTML ValidatorCatch unclosed, mismatched and stray HTML tags with a fast structural check.
Minify HTMLShrink HTML by removing comments and collapsing whitespace.
HTML EscapeEscape HTML special characters so text renders literally instead of as markup.
HTML UnescapeDecode HTML entities back into their original characters.
HTML to JadeConvert HTML into Jade/Pug template syntax.
Jade to HTMLConvert Jade/Pug template syntax into HTML.

CSS & preprocessors

Beautify or minify CSS and convert between CSS, Less, Sass, SCSS and Stylus.

CSS BeautifierBeautify and format messy or minified CSS into clean, consistent, readable code using Prettier.
CSS Pretty PrintFormat and beautify messy or minified CSS with Prettier right in your browser.
Minify CSSMinify CSS instantly in your browser.
LESS FormatterFormat and beautify LESS code in your browser with Prettier.
SCSS FormatterFormat and beautify SCSS code in your browser using Prettier.
CSS to LESSConvert and format CSS as LESS in your browser.
CSS to SASSConvert standard CSS to the indented SASS (.sass) syntax.
CSS to SCSSConvert CSS to SCSS instantly in your browser.
CSS to StylusConvert CSS to Stylus indented syntax in your browser.
LESS to CSSCompile LESS into plain CSS right in your browser.
SASS to CSSConvert indented SASS syntax to CSS in your browser.
SCSS to CSSCompile SCSS to CSS in your browser.
Stylus to CSSConvert Stylus to CSS in your browser.
LESS to SASSConvert LESS into SASS (indented .sass) syntax in your browser.
LESS to SCSSConvert LESS source to SCSS syntax in your browser.
LESS to STYLUSConvert LESS to Stylus syntax in your browser.
SASS to LESSConvert SCSS/SASS syntax to LESS in your browser.
SASS to SCSSConvert indented SASS syntax to brace-and-semicolon SCSS in your browser.
SASS to STYLUSConvert SASS/SCSS source to Stylus syntax in your browser.
SCSS to LESSConvert SCSS syntax to LESS in your browser.
SCSS to SASSConvert SCSS to the indented SASS syntax in your browser.
SCSS to STYLUSConvert SCSS to Stylus syntax in your browser.
STYLUS to LESSConvert Stylus stylesheets to LESS syntax in your browser.
STYLUS to SASSBest-effort converter from Stylus to the SASS indented syntax.
STYLUS to SCSSConvert Stylus to SCSS syntax in your browser.

Code formatters & escapers

Prettier-style formatting for JavaScript, TypeScript, frameworks, SQL, PHP, Java, C# and Markdown.

Code and Data FormattersEvery CalcCafe formatter and beautifier in one place — JSON, XML, YAML, HTML, CSS/SCSS/LESS and many…
JS BeautifierBeautify minified or messy JavaScript into readable code.
JavaScript Pretty PrintPretty-print and beautify JavaScript into clean, consistent code.
JavaScript EscapeEscape text into a JavaScript string literal (quotes, backslashes, newlines).
JavaScript UnescapeTurn an escaped JavaScript string back into plain text.
TypeScript FormatterFormat TypeScript with Prettier — consistent indentation, quotes and semicolons.
Babel FormatterFormat modern JavaScript (Babel parser) including JSX and the latest syntax.
Angular FormatterFormat Angular HTML templates with consistent structure.
Vue FormatterFormat Vue single-file components — template, script and style.
LWC FormatterFormat Lightning Web Components HTML templates.
Glimmer FormatterFormat Glimmer / Handlebars (.hbs) templates.
GraphQL FormatterFormat GraphQL schemas and queries with consistent indentation.
Markdown FormatterFormat Markdown — normalise headings, lists, spacing and tables.
MDX FormatterFormat MDX (Markdown + JSX) documents cleanly and consistently.
PHP FormatterRe-indent PHP code consistently based on brace depth.
Java FormatterRe-indent Java code consistently based on brace depth.
Java EscapeEscape any text into a Java string literal body.
Java UnescapeDecode Java string escape sequences (\n, \t, \", \\, \uXXXX, octal \nnn) back into plain readable text,…
C# FormatterRe-indent C# code consistently based on brace depth.
C#/.NET EscapeEscape any text into a C# string literal body.
C#/.NET UnescapeDecode C#/.NET string escape sequences back to plain text.
SQL FormatterFormat and beautify SQL queries online — Postgres, MySQL, SQLite, BigQuery and more.
SQL EscapeEscape a string for safe use inside SQL single-quoted literals: doubles single quotes and escapes backslashes.
SQL UnescapeReverse SQL string escaping in your browser.

Developer utilities

Diff, regex, JWT, UUIDs, URL encoding, cron, curl, .env and .gitignore generators, and cloud cost estimates.

Diff CheckerCompare two pieces of text or code and see exactly what changed, line by line — added in green, removed in…
Regex TesterTest and debug regular expressions live — see every match highlighted, with capture groups.
JWT DecoderDecode a JSON Web Token to read its header and payload, and check the expiry — all in your browser.
UUID GeneratorGenerate random version-4 UUIDs in bulk, instantly, in your browser.
URL EncodePercent-encode text for safe use in URLs using encodeURIComponent.
URL DecodeDecode percent-encoded URL strings back to readable text.
Cron Expression GeneratorBuild and test cron expressions and see the next scheduled run times.
cURL Command BuilderBuild a ready-to-run cURL command from a URL, method, headers and body.
ENV File GeneratorBuild a clean .env file from key/value pairs, with proper quoting.
.gitignore GeneratorGenerate a .gitignore for your stack — Node, Python, Java, macOS, VS Code and more.
String UtilityFree online string utility.
Server Header CheckerFetch a URL from your browser and inspect its HTTP response headers.
Password Entropy CalculatorMeasure password strength in bits of entropy.
Cloud Cost CalculatorEstimate your monthly and annual cloud bill from compute, storage and egress.
Cloud Storage Cost CalculatorEstimate your monthly and annual object-storage bill.
All Developer ToolsThe CalcCafe developer toolbox — formatters, converters, validators and generators for JSON, XML, YAML,…

Sources & references

These tools follow our methodology and provide educational estimates only — verify important figures with a qualified professional.