Free online developer tools
JSON and code formatters, Base64, URL and JWT decoders, hash generators, UUID, regex, timestamp and cron tools, PDF tools, plus QR code and barcode generators — all private, browser-only, no signup.
JSON & Data Tools
Format, validate, compare, and convert JSON, CSV, and XML data.
JSON Formatter & Validator
Pretty print, beautify, minify, and validate JSON online free. Tree view, file upload, private browser-only.
JSON Diff Checker
Compare two JSON files side by side and highlight added, removed, and modified keys. Free online JSON difference finder.
JSON to XML Converter
Convert JSON to XML and XML to JSON online free. Custom root element, file upload, copy, and download.
CSV to JSON Converter
Convert CSV to JSON and JSON to CSV online free. Custom delimiters, headers, paste or upload a file.
Code Formatters
Beautify, minify, and preview HTML, CSS, JavaScript, Markdown, SQL, XML, and YAML.
HTML Formatter
Beautify messy or minified HTML with clean indentation, or minify it for production. Free and private.
HTML CSS Preview
Write HTML, CSS, and JavaScript and see the result live. Responsive sizes, console output, and download.
Markdown Preview
Open .md files and preview Markdown live, GitHub-style. Edit with a toolbar and convert Markdown to HTML.
CSS Formatter
Beautify minified CSS into readable rules, or minify CSS to reduce file size. Runs in your browser.
JavaScript Formatter
Beautify and unminify JavaScript code with consistent indentation. Supports modern ES2024 syntax.
SQL Formatter
Format SQL queries for MySQL, PostgreSQL, SQL Server, Oracle, SQLite, BigQuery, and more.
XML Formatter
Pretty print, validate, and minify XML with clear error messages for malformed documents.
YAML Formatter
Format, validate, and convert YAML to JSON (or JSON to YAML) online free. Beautify and minify in your browser.
Encoders & Decoders
Encode and decode Base64, URLs, and JSON Web Tokens.
Base64 Encoder
Encode text, files, and images to Base64 or data URIs. UTF-8 safe, with URL-safe Base64URL option.
Base64 Decoder
Decode Base64 and Base64URL strings to text, or back to images and files. UTF-8 safe.
URL Encoder
Percent-encode text, query strings, and URLs. Choose component or full-URL encoding.
URL Decoder
Decode percent-encoded URLs and query strings, and see every query parameter in a table.
JWT Decoder
Decode JSON Web Tokens to read the header, payload, and claims, and check if a token has expired.
Hash Generators
Generate MD5, SHA-1, SHA-256, SHA-512, and HMAC hashes for text and files.
Hash Generator
Generate MD5, SHA-1, SHA-256, SHA-384, and SHA-512 hashes of text or files at once. HMAC supported.
MD5 Hash Generator
Create an MD5 hash of any text or file and verify MD5 checksums. Instant and private.
SHA-256 Hash Generator
Generate SHA-256 and HMAC-SHA256 hashes of text or files, and verify SHA-256 checksums.
Developer Utilities
UUIDs, regular expressions, Unix timestamps, and cron schedules.
UUID Generator
Generate random UUID v4 or time-ordered UUID v7 in bulk, and validate existing UUIDs/GUIDs.
Regex Tester
Test JavaScript regular expressions with live match highlighting, capture groups, and replace.
Unix Timestamp Converter
Convert Unix epoch timestamps to dates and dates to timestamps. Seconds, milliseconds, UTC, and local time.
Cron Expression Generator
Build and explain cron expressions in plain English and preview the next run times.
PDF Tools
Crop, delete, insert, and add pages to PDFs without uploading them.
PDF Cropper
Crop all PDF pages at once and remove white margins online free. No upload, no watermark.
PDF Page Manager
Delete pages from a PDF, insert blank pages, add pages from another PDF, or add images as pages. Free and private.
QR & Barcode
Create QR codes and barcodes and download them as PNG.
QR Code Generator
Free QR code generator for links, WhatsApp, WiFi, email, SMS, phone, and vCard. Download PNG or copy Base64.
Barcode Generator
Free barcode generator for CODE128, CODE39, EAN-13, EAN-8, UPC-A, and ITF-14. Download PNG or copy Base64.
Resources
Tutorials, fixes, and guides that go with the tools.
Privacy & security
All tools run entirely in your browser. Your data is never uploaded to any server. Refresh or close the tab and your input is cleared.