Free Online Developer Tools
Inspect API data, encode values, debug patterns and generate identifiers. These tools cover common development tasks without sending your input to an application server.
Structured data and configuration
Format API responses, move between YAML and JSON, and inspect XML without uploading documents. Conversion checks syntax, not an application-specific schema.
JSON Formatter & Validator
Format and validate JSON with readable indentation.
Open tool Developer ToolsJSON Minifier
Remove unnecessary whitespace from valid JSON.
Open tool Developer ToolsYAML to JSON Converter
Convert YAML maps and sequences to indented JSON with local syntax checks.
Open tool Developer ToolsJSON to YAML Converter
Convert valid JSON into readable YAML configuration without uploading data.
Open tool Developer ToolsXML Formatter
Pretty-print XML with basic validation and readable nested elements.
Open toolSource formatting and debugging
Inspect HTML as text, compact CSS and JavaScript, and test JavaScript regular expressions. Formatters do not execute the supplied source.
HTML Formatter
Format HTML source as inert text with two- or four-space indentation.
Open tool Developer ToolsCSS Minifier
Minify CSS with a local parser while preserving strings and important comments.
Open tool Developer ToolsJavaScript Minifier
Minify JavaScript locally with Terser without evaluating the supplied code.
Open tool Developer ToolsRegex Tester
Test JavaScript regular expressions and inspect matches.
Open toolEncoding, identity and time
Decode transport values, inspect token claims and create identifiers. Decoding a JWT does not validate its signature, and hashing is not encryption.
Base64 Encoder & Decoder
Encode and decode UTF-8 text without losing Unicode.
Open tool Encoding & ConversionURL Encoder & Decoder
Encode or decode a URL component safely.
Open tool Security & GeneratorsJWT Decoder
Inspect JWT headers and payloads locally.
Open tool Developer ToolsUnix Timestamp Converter
Convert Unix seconds, milliseconds and local dates.
Open tool Security & GeneratorsUUID Generator
Generate random version 4 UUIDs using browser cryptography.
Open tool Security & GeneratorsSHA Hash Generator
Generate SHA-256, SHA-384 or SHA-512 hex digests from UTF-8 text locally.
Open tool Security & GeneratorsRandom String Generator
Generate configurable random strings for test data and development identifiers.
Open tool Security & GeneratorsPassword Generator
Create random passwords with configurable character sets.
Open toolFind more useful tools
Browse the complete directory or explore the developer, Flutter & Dart and utility collections, or try the AI & LLM tools.