Free Online Developer Tools
Ship faster with browser-based developer utilities. Validate JSON, decode JWTs, minify CSS/JS, format HTML, generate hashes, and test dummy APIs without leaving FYNTools.
17 tools
All Developer Tools
JSON Beautifier & Formatter
Beautify, format, validate, and minify JSON data online. Free JSON beautifier and minifier tool.
Hash Generator & Comparator
Generate and compare cryptographic hashes using MD5, SHA-1, SHA-256, and SHA-512 algorithms. Verify encrypted data by comparing plain text with hash values.
JWT Token Decoder
Decode and parse JWT (JSON Web Token) headers, payloads, and signatures.
Meta Tag Previewer
Preview how your website appears in search results and generate SEO meta tags.
Live HTML Previewer
Instantly preview HTML, CSS, and JavaScript code online. Real-time HTML preview, test HTML code online, HTML editor with live preview.
JavaScript Minifier
Minify JavaScript code to reduce file size.
Table to JSON Converter
Convert HTML tables to JSON format.
XML Sitemap Tester & Validator
Test and validate your XML sitemap for SEO issues. Analyze URLs, detect broken links, check redirects, and get actionable recommendations.
Box Shadow Generator
Create and customize CSS box-shadow effects for your web elements.
Border Radius Generator
Generate CSS border-radius properties for rounded corners.
Button Generator
Design custom CSS buttons with 40+ fonts, 24 presets, hover gradients, animations, stickers (animals, pets, birds, nature) and image icons — copy HTML/CSS/React.
CSS Minifier
Free CSS minifier online tool to compress and optimize CSS code. Best CSS minifier with color optimization, comment removal, and size reduction.
Gradient Generator
Create custom CSS gradients with multiple colors and directions.
HTML Formatter
Format and beautify HTML code for better readability.
JSON Validator
Validate and format JSON data for accuracy and readability.
URL Encode Decode
Encode URLs for safe transmission or decode URL-encoded strings instantly.
Dummy API Generator
Free dummy REST API for students and developers to practice login, CRUD, and authentication testing with live endpoints.
Developer Tools FAQ
Quick answers for people browsing this category. Open any tool above when you are ready to run a conversion, lookup, timer, or typing session in your browser—no install required.
- Are these tools safe for production secrets?
- Avoid pasting production secrets into any online tool. Prefer local tooling for highly sensitive material.
- Is there a dummy API for practice?
- Yes — Dummy API Generator provides REST endpoints for login/CRUD practice.
- Do formatters change my code semantics?
- Formatters preserve meaning while adjusting whitespace/structure. Always diff critical changes.