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300+ Free Online Tools

Fast, free, and no sign-up required. Tools for developers, writers, designers, and everyday use — all running entirely in your browser.

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Popular Tools

JSON Formatter

Format, beautify, and validate JSON instantly. Paste raw JSON and get a clean, indented, human-readable output with syntax error detection.

JSON Minifier

Minify and compress JSON by removing whitespace and comments. Reduce JSON payload size instantly for faster API responses and smaller storage footprint.

JSON to CSV Converter

Convert JSON arrays to CSV format instantly. Transform nested JSON data into spreadsheet-ready CSV files with automatic header detection.

JSON to YAML Converter

Convert JSON to YAML format instantly online. Transform JSON config files, API schemas, and data structures into clean, readable YAML syntax.

Base64 Encoder / Decoder

Encode text or decode Base64 strings instantly online. Convert between plain text and Base64 encoding for data URLs, authentication headers, and API tokens.

URL Encoder / Decoder

Encode or decode URLs and query strings instantly. Convert special characters to percent-encoding and back for safe URL transmission and debugging.

HTML Encoder / Decoder

Encode special characters to HTML entities or decode HTML entities back to plain text. Prevent XSS and display HTML code safely in web pages.

UUID Generator

Generate UUID v1, v4, and v5 universally unique identifiers instantly. Create single or bulk UUIDs for databases, APIs, and distributed systems.

Regex Tester

Test and debug regular expressions in real time. Highlights matches, capture groups, and supports JavaScript regex flags for instant pattern validation.

JWT Decoder

Decode and inspect JSON Web Tokens (JWTs) instantly. View header, payload, and signature without a secret key. Debug authentication tokens safely.

Hash Generator

Generate cryptographic hashes for any text using MD5, SHA-1, SHA-256, SHA-512, and more. Verify data integrity and create checksums instantly online.

HTML to Markdown Converter

Convert HTML to clean Markdown syntax instantly. Transform web content, blog posts, and documentation from HTML tags to readable Markdown format.

Markdown to HTML Converter

Convert Markdown to HTML instantly online. Transform README files, blog posts, and documentation written in Markdown into clean HTML output.

CSS Minifier

Minify and compress CSS code instantly online. Remove whitespace, comments, and redundant code to reduce CSS file size and improve page load speed.

JavaScript Minifier

Minify and compress JavaScript code online. Remove whitespace, comments, and shorten variable names to reduce JS bundle size and improve load time.

HTML Minifier

Minify HTML by removing whitespace, comments, and optional tags. Reduce HTML document size to improve page load speed and server response times.

SQL Formatter

Format and beautify SQL queries instantly online. Clean up minified or messy SQL with proper indentation, keyword capitalisation, and clause alignment.

XML Formatter

Format and beautify XML documents instantly online. Validate XML structure, add proper indentation, and make raw XML human-readable with one click.

Cron Job Generator

Free cron job generator with visual builder. Create cron expressions for Linux crontab, AWS, GitHub Actions, Kubernetes. See next run times instantly.

Color Converter

Convert colors between HEX, RGB, RGBA, HSL, HSLA, and HSV formats instantly. Pick colors visually and get all format values at once for CSS and design work.

Why Utilko?

Free, no signup

Every tool is completely free with no account, no trial, no paywall. Ads support the site — never the tools.

Private by design

Tools run entirely in your browser. Data you paste in — JSON, passwords, images — never reaches our servers.

Instant & offline-capable

Most tools keep working after page load, even with the internet disconnected. No round-trips for basic operations.

Embeddable & open API

Drop any tool onto your site with one line of HTML. A free JSON API exposes the catalog for integrations.

Frequently Asked Questions

What is Utilko?
Utilko is a free online tool library with 300+ web-based utilities for developers, writers, designers, students, and everyday users. Every tool runs entirely in your browser — no account, no uploads, no tracking. Popular tools include the JSON formatter, password generator, image compressor, QR code generator, percentage calculator, and BMI calculator.
Are Utilko tools really free?
Yes. Every tool on Utilko is 100% free with no usage limits, no paywalls, and no sign-up. We display unobtrusive ads to support the site, but the tools themselves have no restrictions or premium tiers.
Do Utilko tools work offline?
Most tools continue working after the page loads, because the computation happens in your browser rather than on a server. You can verify this by opening a tool, disconnecting from the internet, and using it — the JSON formatter, password generator, image compressor, and calculators all work without a connection.
Is my data safe when I use Utilko?
Yes. For most tools, the data you enter never leaves your device — all processing runs client-side in your browser. No JSON you format, password you generate, or image you compress is uploaded or logged. This is the opposite of many "free online tool" sites that send everything to a server.
Can I embed Utilko tools on my own website?
Yes. Every tool has an <iframe> embed code shown on its page, and there is also a JavaScript widget at utilko.com/widget.js that renders any tool inline. Both are free and require no attribution.
Does Utilko have an API?
Yes. Utilko exposes a free public JSON API at utilko.com/api/tools that returns the full tool catalog. It is intended for tool-directory sites, AI agents, and integrations that want to surface Utilko tools.