Free Developer Tools

Developer Tools

Fast, free and private - every tool runs entirely in your browser. No uploads, no signup, no limits.

31tools

JSON Tools

JSON FormatterBeautify and pretty-print JSON with custom indentation.JSON ValidatorValidate JSON syntax and pinpoint errors with line numbers.JSON MinifierCompress JSON by stripping whitespace to shrink payloads.JSON to TypeScriptGenerate TypeScript interfaces from any JSON object.JSON to C#Convert JSON into C# classes with properties and attributes.JSON to CSVTurn arrays of JSON objects into downloadable CSV files.JSON ↔ YAMLConvert between JSON and YAML in both directions.

Encoders & Security

JWT DecoderDecode JWT headers and payloads, check expiry - all offline.Base64 Encoder / DecoderEncode text to Base64 or decode it back, UTF-8 safe.URL Encoder / DecoderPercent-encode or decode URLs and query strings.Hash GeneratorGenerate SHA-1, SHA-256, SHA-384 and SHA-512 hashes.HTML Entity EncoderEscape and unescape HTML entities to prevent XSS.

Converters

CSS FormatterPretty-print minified CSS into clean, readable rules.CSS MinifierCompress CSS by removing whitespace, comments and extra formatting.Markdown to HTMLConvert Markdown text into clean HTML markup.HTML to MarkdownConvert rich HTML into readable Markdown text.WebP ConverterConvert PNG and JPG images to WebP right in your browser.Unix Timestamp ConverterConvert Unix epoch timestamps to human-readable dates and back.HEX / RGB / HSL ConverterConvert colors between HEX, RGB and HSL with a live preview.cURL to JavaScript FetchTranslate cURL commands into modern fetch() code.

Generators

UUID GeneratorGenerate cryptographically random UUID v4 identifiers in bulk.Cron Expression GeneratorBuild cron schedules visually with a plain-English preview.

Productivity

SEO Article WriterWrite articles in a block editor with Yoast-style SEO analysis.NotepadA distraction-free online notepad that autosaves as you type.WhiteboardSketch, draw shapes and jot ideas on a free online whiteboard.

Text & Code

Regex TesterTest regular expressions with live match highlighting.Text Diff CheckerCompare two texts line by line and see what changed.JavaScript FormatterPretty-print minified JavaScript into readable, formatted code.JavaScript ObfuscatorRename and disguise JavaScript to make it harder to read and understand.SQL FormatterFormat and beautify SQL queries for readability.HTML PreviewWrite HTML and see it rendered live in a sandboxed preview.

Free browser-based tools for developers

This is a growing toolbox of free online developer tools built with plain JavaScript - no servers, no accounts and no tracking of the data you paste. Everything from theJSON formatter to theJWT decoder and theWebP converter runs entirely inside your browser, so tokens, credentials, source code and images never leave your machine.

Whether you need to validate an API response, decode a Base64 string, test a regular expression, generate UUIDs, build a cron schedule or convert colors between HEX, RGB and HSL - there is a fast, distraction-free tool here for it. Bookmark this page and skip the ad-heavy alternatives.