Utilitoo
Online tools for everyone
Free online tools for developers, writers, and everyday tasks - JSON formatters, calculators, text utilities, and more. Fast, private, no signup required.
Utilitoo is a collection of free, browser-based utilities for developers, writers, students, and anyone who needs quick answers without installing software or creating an account. From JSON formatters and JWT decoders to PDF tools, calculators, and text utilities, everything runs in one place so you can get work done faster.
Privacy is built in: most tools process your input entirely on your device. Text, files, and data you paste into a tool are not uploaded to our servers for processing. That makes Utilitoo a practical choice for API payloads, config files, documents, and everyday calculations where you do not want your data leaving your browser.
Start with the featured tools below, browse by category, or search if you already know the job. New utilities are added when they earn a place - not as a bulk catalog dump. The site is free to use with optional Pro features planned for the future.
Beyond the widgets, we publish short guides on the Blog and share how the project is built on About. Need a tool that is not featured? Open a category - the full set of 121 utilities lives there, with instructions, use cases, and FAQs on each page.
Featured tools
Start here. These pages solve a specific job: locale tags, YAML and JSON, bcrypt hashes, slugs, user-agent strings, and a few other workflows that need more than a cloned widget.
Locale Converter
Convert BCP 47, POSIX, and Accept-Language locale strings.
YAML to JSON
Convert YAML documents into JSON format.
JSON to YAML
Convert JSON documents into YAML format.
Bcrypt Generator
Generate bcrypt password hashes with adjustable cost.
Slug Generator
Generate URL-friendly slugs from text.
User Agent Parser
Parse browser user agent strings.
JSON Formatter
Format and beautify JSON online instantly.
Mermaid Editor
Edit Mermaid diagrams with live preview and export SVG or PNG.
JWT Decoder
Decode JWT tokens and inspect claims.
Regex Tester
Test regular expressions against sample text.
Color Name from Photo
Find a human-friendly color name from any photo you upload.
Merge PDF
Combine multiple PDF files into one document.
Browse by category
Every live tool is one click away from these hubs - developer, text, security, time, PDF, calculators, and home and garden.
PDF Tools
Merge, split, convert, and edit PDFs in your browser
Developer Tools
JSON, encoding, regex, and dev utilities
Time Tools
Timezones, timers, and date calculators
Calculators
Financial, math, and everyday calculators
Text Tools
Word count, case conversion, and text utilities
Security Tools
Passwords, hashing, and encryption utilities
Home & Garden Tools
Decor colors, garden planning, and home project helpers
From the blog
Practical notes on formats and pitfalls, each linked to the matching tools.
POSIX to BCP 47 Locale Conversion Pitfalls
Why en_US.UTF-8 is not the same as en-US, how Accept-Language quality weights work, and how to convert locale strings for HTML, JavaScript Intl, and shells.
Bcrypt vs SHA-256 for Passwords
SHA-256 is a checksum, not a password store. See unsalted hash failures, how bcrypt salt and cost work, and how to check hashes in the browser.
YAML to JSON Conversion Pitfalls
Why YAML-to-JSON conversions fail in CI and Kubernetes workflows - indentation, types, multiline strings, and what to check before you paste the result into an API.