Diff checker / compare text
Compare two texts and highlight the differences line by line and word by word. Find added, removed, and changed text privately in your browser.
Free web browser tools
Developer
Paste code or data and get formatted, encoded, or converted output without uploading anything.
JSON formatter & validator
Format, beautify, validate, and minify JSON online. Pinpoint syntax errors by line and column, sort keys, and copy or download the result.
Color picker & converter
Pick a color and convert between HEX, RGB, HSL, HSV, and CMYK. See tints, shades, and contrast ratios against black and white.
Image to Base64
Convert images to Base64 data URIs for HTML and CSS, or decode Base64 back to an image. Copy ready-to-use snippets instantly.
Color palette from image
Extract the dominant colors from any photo or design. Get HEX and RGB values, click to copy, and export the palette as CSS.
Markdown editor
Write Markdown with a live preview, formatting toolbar, and auto-save. Export to Markdown or HTML — everything stays in your browser.
Base64 encode / decode
Encode text to Base64 or decode Base64 back to text with full UTF-8 support and an optional URL-safe alphabet.
Unix timestamp converter
Convert Unix epoch timestamps to human-readable dates and back. Supports seconds and milliseconds, local time, UTC, and ISO 8601.
Hash generator
Generate MD5, SHA-1, SHA-256, SHA-512, SHA3, and CRC32 hashes for text or files. Verify checksums and create HMACs locally.
Regex tester
Test JavaScript regular expressions with live match highlighting, capture groups, flags, and replace preview.
JSON to CSV converter
Convert JSON to CSV and CSV to JSON online. Flattens nested objects, supports custom delimiters, and previews the table — all in your browser.
Number base converter
Convert numbers between binary, octal, decimal, hexadecimal, and any base from 2 to 36. Handles huge integers and negative numbers.
URL encode / decode
Encode or decode URLs and query strings with percent-encoding, and break any URL into its parts and parameters.
JWT decoder
Decode JSON Web Tokens to inspect the header and payload, check expiry, and verify HS256, RS256, and ES256 signatures — tokens never leave your browser.
CSS gradient generator
Design linear, radial, and conic CSS gradients with a live preview. Add color stops, set angles, and copy the CSS.
Cron expression generator
Build and explain cron schedules in plain English. See the next run times, validate expressions, and start from common presets.
SQL formatter
Format and beautify SQL queries for MySQL, PostgreSQL, SQL Server, SQLite, BigQuery, and more. Choose keyword case and indentation.
UUID generator
Generate random UUID v4 or time-ordered UUID v7 identifiers in bulk. Copy or download as text, with uppercase and no-hyphen options.
XML formatter
Pretty-print, validate, and minify XML. Pinpoints syntax errors and keeps comments, CDATA, and attributes intact.
YAML to JSON converter
Convert YAML to JSON and JSON to YAML instantly. Validates syntax and supports multi-document YAML files.
Favicon generator
Create a complete favicon set from an image, text, or emoji: favicon.ico, PNG sizes, Apple touch icon, Android icons, and the HTML to paste in.
HTML entity encoder / decoder
Escape special characters as HTML entities or decode entities back to text. Supports named, decimal, and hex entities.
Developer FAQs
How are tags used on ReallyUseful.Tools?
Tags group tools by shared traits such as file converter, in browser, or privacy friendly so you can filter the directory by feature.